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Lopinavir and Ritonavir

Medically reviewed by Drugs.com. Last updated on Oct 3, 2020.

Pronunciation

(loe PIN a veer & ri TOE na vir)

Index Terms

  • Coronavirus
  • COVID-19
  • Lopinavir/Ritonavir
  • Ritonavir and Lopinavir

Dosage Forms

Excipient information presented when available (limited, particularly for generics); consult specific product labeling.

Solution, oral:

Kaletra: Lopinavir 80 mg and ritonavir 20 mg per 1 mL (160 mL) [contains ethanol 42.4%, menthol, propylene glycol; cotton candy flavor]]

Tablet:

Kaletra:

Lopinavir 100 mg and ritonavir 25 mg

Lopinavir 200 mg and ritonavir 50 mg

Brand Names: U.S.

  • Kaletra

Pharmacologic Category

  • Antiretroviral, Protease Inhibitor (Anti-HIV)

Pharmacology

A coformulation of lopinavir and ritonavir. The lopinavir component binds to the site of HIV-1 protease activity and inhibits the cleavage of viral Gag-Pol polyprotein precursors into individual functional proteins required for infectious HIV. This results in the formation of immature, noninfectious viral particles. The ritonavir component inhibits the CYP3A metabolism of lopinavir, allowing increased plasma levels of lopinavir.

Metabolism

Lopinavir: Hepatic via CYP3A4; 13 metabolites identified; may induce its own metabolism

Excretion

Lopinavir: Feces (83%, 20% as unchanged drug); urine (10%; <3% as unchanged drug)

Clearance: (Apparent oral): 6 to 7 L/hour

Time to Peak

Lopinavir: ~4 hours

Half-Life Elimination

Lopinavir: 5 to 6 hours

Protein Binding

Lopinavir: 98% to 99%; binds to both alpha-1 acid glycoprotein and albumin; higher affinity for alpha-1 acid glycoprotein; decreased with mild-to-moderate hepatic dysfunction

Special Populations: Hepatic Function Impairment

Lopinavir is principally metabolized and eliminated by the liver. Multiple dosing of lopinavir 400 mg/ritonavir 100 mg twice daily to patients coinfected with HIV-1 and hepatitis C virus with mild to moderate hepatic impairment resulted in a 30% increase in lopinavir AUC and a 20% increase in Cmax compared with patients infected with HIV-1 with normal hepatic function.

Use: Labeled Indications

HIV-1 infection, treatment: Treatment of HIV-1 infection in adults and pediatric patients 14 days and older in combination with other antiretroviral agents.

Note: Lopinavir/ritonavir is not recommended as a component of initial therapy for the treatment of HIV (HHS [adults] 2019).

Contraindications

Hypersensitivity (eg, toxic epidermal necrolysis, Stevens-Johnson syndrome, erythema multiforme, urticaria, angioedema) to lopinavir, ritonavir, or any component of the formulation; coadministration with drugs that are highly dependent on CYP3A for clearance and for which elevated plasma concentrations are associated with serious and/or life-threatening reactions or with potent CYP3A inducers where significantly decreased lopinavir levels may be associated with a potential for loss of virologic response and resistance and cross-resistance to develop (eg, alfuzosin, apalutamide, cisapride, colchicine [patients with renal and/or hepatic impairment], dronedarone, elbasvir/grazoprevir, ergot derivatives [eg, dihydroergotamine, ergotamine, methylergonovine], lomitapide, lovastatin, lurasidone, oral midazolam, pimozide, ranolazine, rifampin, sildenafil [when used to treat pulmonary arterial hypertension], simvastatin, St John's wort, triazolam).

Canadian labeling: Additional contraindications (not in US labeling):

Tablets, oral solution: Coadministration with apalutamide, astemizole (not available in Canada), fusidic acid, salmeterol, terfenadine (not available in Canada), vardenafil, venetoclax (during dose initiation and the ramp-up phase).

Oral solution: Pregnancy; hepatic or renal failure; coadministration with disulfiram or metronidazole.

Dosing: Adult

Coronavirus disease 2019 (COVID-19): Lopinavir/ritonavir is currently under investigation for use in the treatment of COVID-19 (See ClinicalTrials.gov). At this time, safety and efficacy have not been established (Cao 2020); lopinavir/ritonavir should only be given for COVID-19 as part of a clinical trial (HHS 2020; IDSA [Bhimraj 2020]).

HIV-1 infection, treatment (as a component of combination therapy): Oral:

Note: Lopinavir/ritonavir is not recommended as a component of initial therapy for the treatment of HIV (HHS [adults] 2019).

Patients receiving concomitant antiretroviral therapy without efavirenz, nelfinavir, or nevirapine:

Twice-daily dosing: Therapy-naive or therapy-experienced: Lopinavir 400 mg/ritonavir 100 mg twice daily.

Once-daily dosing: Therapy-naive or experienced patients with <3 lopinavir resistance-associated substitutions: Lopinavir 800 mg/ritonavir 200 mg once daily. Once-daily dosing is not recommended in those receiving efavirenz, fosamprenavir, nevirapine, nelfinavir, carbamazepine, phenobarbital, or phenytoin.

Pregnant women (with no lopinavir-resistance-associated amino acid substitutions): Lopinavir 400 mg/ritonavir 100 mg twice daily. Once-daily dosing is not recommended. Tablets are recommended; avoid use of the oral solution. Alternately, the HHS perinatal guidelines recommend an increased dose of lopinavir 600 mg/ritonavir 150 mg twice daily, or lopinavir 500 mg/ritonavir 125 mg twice daily, during the second and third trimesters of pregnancy, especially in PI-experienced pregnant women and women with a baseline viral load >50 copies/mL. If standard doses are used, close monitoring is recommended (HHS [perinatal] 2019).

Dosage adjustment for combination therapy with efavirenz, nelfinavir, or nevirapine: Oral:

Twice-daily dosing: Therapy-naive and therapy-experienced patients:

Solution: Lopinavir 520 mg/ritonavir 130 mg (6.5 mL) twice daily

Tablet: Lopinavir 500 mg/ritonavir 125 mg twice daily

Once-daily dosing: Once-daily dosing not recommended.

Dosage adjustment for concomitant therapy: Significant drug interactions exist, requiring dose/frequency adjustment or avoidance. Consult drug interactions database for more information.

Dosing: Pediatric

Coronavirus disease 2019 (COVID-19): Lopinavir/ritonavir is currently under investigation for use in the treatment of COVID-19 (See ClinicalTrials.gov). At this time, safety and efficacy have not been established in adult or pediatric patients; lopinavir/ritonavir should only be given for COVID-19 as part of a clinical trial (Cao 2020; Chiotos 2020; HHS 2020; IDSA [Bhimraj 2020]).

Note: Gene mutation and antiretroviral (ARV) resistance patterns should be evaluated (refer to https://www.iasusa.org/ for more information) when necessary. Health care providers are reminded that lopinavir/ritonavir oral solution is highly concentrated. Dosage is based on patient body weight (mg/kg) or body surface area (mg/m2); use precaution during dose calculation; dosing is presented based on lopinavir component. To minimize the risk for medication errors, health care providers should pay special attention to accurate calculation of the dose, transcription of the medication order, dispensing information, dosing instructions, and proper measurement of the dose. Unlike in adults, once daily dosing is subtherapeutic and not recommended for use in pediatric patients (HHS [pediatric 2020]).

HIV-1 infection, treatment: Oral:

Note: Use in combination with other ARV agents. Use of tablets in patients <15 kg or <0.6 m2 is not recommended; oral solution preferable.

Infants (≥42 weeks PMA) (HHS [pediatric 2020]):

Patients not receiving concomitant efavirenz, nelfinavir, or nevirapine:

Lopinavir 16 mg/kg/dose or 300 mg/m2/dose twice daily.

Note: Infants who receive 300 mg/m2/dose twice daily may have lower trough concentrations compared to adults; evaluate infants and adjust dose for incremental growth at frequent intervals.

Patients with concomitant efavirenz, nelfinavir, or nevirapine: Dosage information does not exist; lopinavir/ritonavir is not recommended in infants who are receiving these agents.

Children and Adolescents:

Patients not receiving concomitant efavirenz, nelfinavir, or nevirapine:

Antiretroviral naive: Note: Higher dose (see below) recommended in antiretroviral-experienced patients who may have decreased sensitivity to lopinavir; some clinicians choose to initiate therapy with the higher dose in all patients due to lower trough concentrations observed with the lower dose (HHS [pediatric 2020]):

BSA-directed dosing: Children and Adolescents: Lopinavir 230 mg/m2/dose (maximum dose: 400 mg/dose) twice daily; others have suggested 300 mg/m2/dose twice daily if the oral solution is used. Note: For patients already receiving lopinavir and ritonavir, an immediate dosage reduction at 12 months of age is not recommended; patients are allowed to "grow into" the 230 mg/m2/dose dosage as they gain weight over time.

Alternate fixed dosing for patients weighing ≥15 kg who are able to swallow tablets: Dosing approximates lopinavir 230 mg/m2/dose:

BSA ≥0.6 to <0.9 m2: Lopinavir 200 mg twice daily.

BSA ≥0.9 to <1.4 m2: Lopinavir 300 mg twice daily.

BSA ≥1.4 m2: Lopinavir 400 mg twice daily.

Weight-directed dosing: Children and Adolescents: Dosing approximates lopinavir 230 mg/m2/dose:

<15 kg: Lopinavir 12 mg/kg/dose twice daily.

15 to 40 kg: Lopinavir 10 mg/kg/dose twice daily.

>40 kg: Lopinavir 400 mg twice daily.

Alternate fixed dosing for patients weighing ≥15 kg and able to swallow tablets: Dosing approximates lopinavir 230 mg/m2/dose:

≥15 to 25 kg: Lopinavir 200 mg twice daily.

>25 to 35 kg: Lopinavir 300 mg twice daily.

>35 kg: Lopinavir 400 mg twice daily.

Antiretroviral-experienced or suspected decreased sensitivity to lopinavir: Note: This dose is also used by some clinicians for initial therapy in all patients (HHS [pediatric 2020]):

BSA-directed dosing: Children and Adolescents: Lopinavir 300 mg/m2/dose (maximum dose: 400 mg/dose) twice daily.

Weight-directed dosing: Children and Adolescents: Dosing approximates lopinavir 300 mg/m2/dose:

<15 kg: Lopinavir 13 mg/kg/dose twice daily.

15 to 45 kg: Lopinavir 11 mg/kg/dose twice daily.

>45 kg: Lopinavir 400 mg twice daily.

Weight-band dosing for children and adolescents weighing ≥15 kg and able to swallow tablets: Dosing approximates lopinavir 300 mg/m2/dose:

15 to 20 kg: 200 mg twice daily.

>20 to 30 kg: 300 mg twice daily.

>30 kg: 400 mg twice daily.

Patients with concomitant efavirenz, nelfinavir, or nevirapine (or treatment-experienced patients not receiving these agents who have suspected decreased susceptibility to lopinavir):

BSA-directed dosing: Children and Adolescents: Lopinavir 300 mg/m2/dose twice daily; maximum dose: Oral solution: 520 mg/dose; Tablet: 500 mg/dose.

Alternate fixed dosing for patients who are able to swallow tablets: Dosing approximates lopinavir 300 mg/m2/dose:

BSA ≥0.6 to <0.8 m2: Lopinavir 200 mg twice daily.

BSA ≥0.8 to < 1.2 m2: Lopinavir 300 mg twice daily.

BSA ≥1.2 to < 1.7 m2: Lopinavir 400 mg twice daily.

BSA ≥1.7 m2: Lopinavir 500 mg twice daily.

Weight-directed dosing: Children and Adolescents: Dosing approximates lopinavir ~300 mg/m2/dose:

<15 kg: Lopinavir 13 mg/kg/dose twice daily.

≥15 to 45 kg: Lopinavir 11 mg/kg/dose twice daily.

>45 kg:

Oral solution: Lopinavir 520 mg (6.5 mL) twice daily.

Tablets: Lopinavir 500 mg twice daily.

Fixed dosing for children and adolescents weighing ≥15 kg who are able to swallow tablets:

≥15 to 20 kg: Lopinavir 200 mg twice daily.

>20 to 30 kg: Lopinavir 300 mg twice daily.

>30 to 45 kg: Lopinavir 400 mg twice daily.

>45 kg: Lopinavir 500 mg twice daily; Note: Alternatively, lopinavir 600 mg twice daily (3 tablets of the 200/50 mg lopinavir/ritonavir) can be used for ease of dosing (HHS [pediatric 2020]).

HIV-1 nonoccupational postexposure prophylaxis (nPEP) (HHS [nPEP] 2016): Note: Initiate therapy within 72 hours of exposure and continue for 28 days; use in combination with other antiretroviral agents. Oral:

Infants (≥42 weeks PMA): Oral solution: 300 mg/m2/dose or 16 mg/kg/dose twice daily.

Children:

Weight-directed dosing: Oral solution:

<15 kg: Lopinavir 12 mg/kg/dose twice daily.

15 to 40 kg: Lopinavir 10 mg/kg/dose twice daily.

>40 kg: Lopinavir 400 mg twice daily.

Fixed dosing: Patients weighing ≥15 kg and able to swallow tablets: Tablets:

≥15 to 25 kg: Lopinavir 200 mg twice daily.

>25 to 35 kg: Lopinavir 300 mg twice daily.

>35 kg: Lopinavir 400 mg twice daily.

Adolescents: Not recommended; other antiretroviral agents should be used.

Dosage adjustment for concomitant therapy: Significant drug interactions exist, requiring dose/frequency adjustment or avoidance. Consult drug interactions database for more information.

Administration

Solution: Must be administered with food; if using didanosine, take didanosine 1 hour before or 2 hours after lopinavir/ritonavir. Administer using calibrated dosing cup or syringe. Contains ethanol and propylene glycol; not recommended for use with polyurethane feeding tubes (potential incompatibility); silicone and polyvinyl chloride feeding tubes may be used.

Tablet: May be taken with or without food. Swallow whole, do not break, crush, or chew. May be taken with didanosine when taken without food.

Dietary Considerations

Solution must be taken with food. Tablet may be taken with or without food

Storage

Oral solution: Store at 2°C to 8°C (36°F to 46°F). Avoid exposure to excessive heat. If stored at 25°C or 77°F, use within 2 months.

Tablet: Store at 20°C to 25°C (68°F to 77°F); excursions permitted to 15°C to 30°C (59°F to 86°F). Exposure to high humidity outside of the original container or USP equivalent tight container for >2 weeks is not recommended.

Drug Interactions

Abacavir: Protease Inhibitors may decrease the serum concentration of Abacavir. Monitor therapy

Abemaciclib: CYP3A4 Inhibitors (Strong) may increase the serum concentration of Abemaciclib. Management: In patients taking abemaciclib at a dose of 200 mg or 150 mg twice daily, reduce the dose to 100 mg twice daily when combined with strong CYP3A4 inhibitors. In patients taking abemaciclib 100 mg twice daily, decrease the dose to 50 mg twice daily. Consider therapy modification

Acalabrutinib: CYP3A4 Inhibitors (Strong) may increase the serum concentration of Acalabrutinib. Avoid combination

Ado-Trastuzumab Emtansine: CYP3A4 Inhibitors (Strong) may increase serum concentrations of the active metabolite(s) of Ado-Trastuzumab Emtansine. Specifically, strong CYP3A4 inhibitors may increase concentrations of the cytotoxic DM1 component. Management: Avoid concomitant use of ado-trastuzumab emtansine and strong CYP3A4 inhibitors when possible. Consider alternatives that do not inhibit CYP3A4 or consider administering after CYP3A4 inhibitor discontinuation. Monitor for toxicities if combined. Consider therapy modification

Afatinib: P-glycoprotein/ABCB1 Inhibitors may increase the serum concentration of Afatinib. Management: If combined, administer the P-gp inhibitor simultaneously with, or after, the dose of afatinib. Monitor closely for signs and symptoms of afatinib toxicity and if the combination is not tolerated, reduce the afatinib dose by 10 mg. Consider therapy modification

Albendazole: Ritonavir may decrease the serum concentration of Albendazole. Monitor therapy

Alfentanil: CYP3A4 Inhibitors (Strong) may increase the serum concentration of Alfentanil. Management: If use of alfentanil and strong CYP3A4 inhibitors is necessary, consider dosage reduction of alfentanil until stable drug effects are achieved. Frequently monitor patients for respiratory depression and sedation when these agents are combined. Consider therapy modification

Alfuzosin: CYP3A4 Inhibitors (Strong) may increase the serum concentration of Alfuzosin. Avoid combination

Aliskiren: P-glycoprotein/ABCB1 Inhibitors may increase the serum concentration of Aliskiren. Monitor therapy

Alitretinoin (Systemic): CYP3A4 Inhibitors (Strong) may increase the serum concentration of Alitretinoin (Systemic). Management: Consider reducing the alitretinoin dose to 10 mg when used together with strong CYP3A4 inhibitors. Monitor for increased alitretinoin effects/toxicities if combined with a strong CYP3A4 inhibitor. Consider therapy modification

Almotriptan: CYP3A4 Inhibitors (Strong) may increase the serum concentration of Almotriptan. Management: Limit initial almotriptan dose to 6.25 mg and maximum dose to 12.5 mg in any 24-period when used with a strong CYP3A4 inhibitor. Avoid concurrent use in patients with impaired hepatic or renal function. Consider therapy modification

Alosetron: CYP3A4 Inhibitors (Strong) may increase the serum concentration of Alosetron. Monitor therapy

Alpelisib: BCRP/ABCG2 Inhibitors may increase the serum concentration of Alpelisib. Management: Avoid coadministration of BCRP/ABCG2 inhibitors and alpelisib due to the potential for increased alpelisib concentrations and toxicities. If coadministration cannot be avoided, closely monitor for increased alpelisib adverse reactions. Consider therapy modification

ALPRAZolam: CYP3A4 Inhibitors (Strong) may increase the serum concentration of ALPRAZolam. Management: Consider using an alternative agent that is less likely to interact. If combined, monitor for increased therapeutic/toxic effects of alprazolam if combined with a strong CYP3A4 inhibitor. Consider therapy modification

Amiodarone: Lopinavir may enhance the QTc-prolonging effect of Amiodarone. Lopinavir may increase the serum concentration of Amiodarone. More specifically, Lopinavir/Ritonavir may increase the serum concentration of Amiodarone. Management: If this combination cannot be avoided, monitor for increased amiodarone serum concentrations and effects as well as for evidence of QT interval prolongation. Avoid combination

Amiodarone: Ritonavir may increase the serum concentration of Amiodarone. Management: Ritonavir US prescribing information lists this combination as contraindicated. Amiodarone use should be avoided with lopinavir/ritonavir, but if the combination must be used, monitor closely for increased amiodarone serum concentrations and effects. Avoid combination

AmLODIPine: CYP3A4 Inhibitors (Strong) may increase the serum concentration of AmLODIPine. Monitor therapy

Antidiabetic Agents: Hyperglycemia-Associated Agents may diminish the therapeutic effect of Antidiabetic Agents. Monitor therapy

Antihepaciviral Combination Products: Lopinavir may increase the serum concentration of Antihepaciviral Combination Products. Specifically, the serum concentrations of the paritaprevir component may increase significantly. Avoid combination

Apalutamide: May decrease the serum concentration of Lopinavir. Avoid combination

Apixaban: Inhibitors of CYP3A4 (Strong) and P-glycoprotein may increase the serum concentration of Apixaban. Management: US labeling recommends a 50% apixaban dose reduction in patients who would otherwise receive 5 or 10 mg twice daily, and avoiding in patients who would otherwise receive 2.5 mg twice daily. Canadian labeling lists any combined use as contraindicated. Consider therapy modification

Aprepitant: CYP3A4 Inhibitors (Strong) may increase the serum concentration of Aprepitant. Avoid combination

ARIPiprazole: CYP3A4 Inhibitors (Strong) may increase the serum concentration of ARIPiprazole. Management: Aripiprazole dose reductions are required for indications other than major depressive disorder. Dose reductions vary based on formulation, CYP2D6 genotype, and use of CYP2D6 inhibitors. See full interaction monograph for details. Consider therapy modification

ARIPiprazole Lauroxil: CYP3A4 Inhibitors (Strong) may increase serum concentrations of the active metabolite(s) of ARIPiprazole Lauroxil. Management: Decrease aripiprazole lauroxil dose to next lower strength if used with strong CYP3A4 inhibitors for over 14 days. No dose adjustment needed if using the lowest dose (441 mg). Max dose is 441 mg in CYP2D6 PMs or if also taking strong CYP2D6 inhibitors. Consider therapy modification

Artesunate: Ritonavir may decrease serum concentrations of the active metabolite(s) of Artesunate. Ritonavir may increase the serum concentration of Artesunate. Monitor therapy

Astemizole: CYP3A4 Inhibitors (Strong) may increase the serum concentration of Astemizole. Management: Drugs listed as exceptions to this monograph are discussed in further detail in separate drug interaction monographs. Avoid combination

Asunaprevir: CYP3A4 Inhibitors (Strong) may increase the serum concentration of Asunaprevir. Avoid combination

Asunaprevir: OATP1B1/1B3 (SLCO1B1/1B3) Inhibitors may increase the serum concentration of Asunaprevir. Avoid combination

AtorvaSTATin: Protease Inhibitors may increase the serum concentration of AtorvaSTATin. Management: See full monograph for recommended dose limits. Avoid atorvastatin with tipranavir/ritonavir. Consider therapy modification

Atovaquone: Ritonavir may decrease the serum concentration of Atovaquone. Monitor therapy

Avanafil: CYP3A4 Inhibitors (Strong) may increase the serum concentration of Avanafil. Avoid combination

Avapritinib: CYP3A4 Inhibitors (Strong) may increase the serum concentration of Avapritinib. Avoid combination

Axitinib: CYP3A4 Inhibitors (Strong) may increase the serum concentration of Axitinib. Management: Avoid concurrent use of axitinib with any strong CYP3A inhibitor whenever possible. If a strong CYP3A inhibitor must be used with axitinib, a 50% axitinib dose reduction is recommended. Consider therapy modification

Barnidipine: CYP3A4 Inhibitors (Strong) may increase the serum concentration of Barnidipine. Avoid combination

Bedaquiline: Lopinavir may increase the serum concentration of Bedaquiline. Management: Consider alternatives to this combination. Concomitant use should only occur if the benefit of coadministration outweighs the risk. If combined, monitor for increased bedaquiline effects/toxicities (eg, QTc interval prolongation). Consider therapy modification

Benperidol: CYP3A4 Inhibitors (Strong) may increase the serum concentration of Benperidol. Monitor therapy

Benzhydrocodone: CYP3A4 Inhibitors (Strong) may increase the serum concentration of Benzhydrocodone. Specifically, the concentration of hydrocodone may be increased. Monitor therapy

Betamethasone (Ophthalmic): CYP3A4 Inhibitors (Strong) may increase the serum concentration of Betamethasone (Ophthalmic). Monitor therapy

Betamethasone (Systemic): CYP3A4 Inhibitors (Strong) may increase the serum concentration of Betamethasone (Systemic). Monitor therapy

Betrixaban: P-glycoprotein/ABCB1 Inhibitors may increase the serum concentration of Betrixaban. Management: Decrease adult betrixaban dose to an initial single dose of 80 mg followed by 40 mg once daily if combined with a P-gp inhibitor. Avoid concomitant use of betrixaban and P-gp inhibitors in patients with severe renal impairment (CrCL less than 30 mL/min). Consider therapy modification

Bictegravir: CYP3A4 Inhibitors (Strong) may increase the serum concentration of Bictegravir. Monitor therapy

Bilastine: P-glycoprotein/ABCB1 Inhibitors may increase the serum concentration of Bilastine. Avoid combination

Blonanserin: CYP3A4 Inhibitors (Strong) may increase the serum concentration of Blonanserin. Avoid combination

Bortezomib: CYP3A4 Inhibitors (Strong) may increase the serum concentration of Bortezomib. Monitor therapy

Bosentan: Protease Inhibitors may increase the serum concentration of Bosentan. Management: Dose adjustment of bosentan and increased monitoring for bosentan toxicities is necessary when these agents are combined. See full drug interaction monograph for details. Consider therapy modification

Bosutinib: CYP3A4 Inhibitors (Strong) may increase the serum concentration of Bosutinib. Avoid combination

Brentuximab Vedotin: CYP3A4 Inhibitors (Strong) may increase the serum concentration of Brentuximab Vedotin. Specifically, concentrations of the active monomethyl auristatin E (MMAE) component may be increased. Monitor therapy

Brexpiprazole: CYP3A4 Inhibitors (Strong) may increase the serum concentration of Brexpiprazole. Management: Reduce brexpiprazole dose 50% with strong CYP3A4 inhibitors; reduce to 25% of usual if used with both a strong CYP3A4 inhibitor and a CYP2D6 inhibitor in patients not being treated for MDD, or strong CYP3A4 inhibitor used in a CYP2D6 poor metabolizer. Consider therapy modification

Brigatinib: CYP3A4 Inhibitors (Strong) may increase the serum concentration of Brigatinib. Management: Avoid concurrent use of brigatinib with strong CYP3A4 inhibitors when possible. If combination cannot be avoided, reduce the brigatinib dose by approximately 50%, rounding to the nearest tablet strength (ie, from 180 mg to 90 mg, or from 90 mg to 60 mg). Consider therapy modification

Bromperidol: CYP3A4 Inhibitors (Strong) may increase the serum concentration of Bromperidol. Monitor therapy

Budesonide (Nasal): CYP3A4 Inhibitors (Strong) may increase the serum concentration of Budesonide (Nasal). Monitor therapy

Budesonide (Oral Inhalation): CYP3A4 Inhibitors (Strong) may increase the serum concentration of Budesonide (Oral Inhalation). Monitor therapy

Budesonide (Systemic): CYP3A4 Inhibitors (Strong) may increase the serum concentration of Budesonide (Systemic). Management: Avoid the concomitant use of CYP3A4 inhibitors and oral budesonide. If patients receive both budesonide and a strong CYP3A4 inhibitor, they should be closely monitored for signs and symptoms of corticosteroid excess. Consider therapy modification

Budesonide (Topical): CYP3A4 Inhibitors (Strong) may increase the serum concentration of Budesonide (Topical). Avoid combination

Buprenorphine: CYP3A4 Inhibitors (Strong) may increase the serum concentration of Buprenorphine. Monitor therapy

BuPROPion: CYP2B6 Inducers (Moderate) may decrease the serum concentration of BuPROPion. Monitor therapy

BusPIRone: CYP3A4 Inhibitors (Strong) may increase the serum concentration of BusPIRone. Management: Limit the buspirone dose to 2.5 mg daily and monitor patients for increased buspirone effects/toxicities if combined with strong CYP3A4 inhibitors. Consider therapy modification

Cabazitaxel: CYP3A4 Inhibitors (Strong) may increase the serum concentration of Cabazitaxel. Management: Concurrent use of cabazitaxel with strong inhibitors of CYP3A4 should be avoided when possible. If such a combination must be used, consider a 25% reduction in the cabazitaxel dose. Consider therapy modification

Cabozantinib: CYP3A4 Inhibitors (Strong) may increase the serum concentration of Cabozantinib. Management: Avoid use of a strong CYP3A4 inhibitor with cabozantinib if possible. If combined, decrease cabozantinib capsules (Cometriq) by 40 mg from previous dose or decrease cabozantinib tablets (Cabometyx) by 20 mg from previous dose. Consider therapy modification

Calcifediol: CYP3A4 Inhibitors (Strong) may increase the serum concentration of Calcifediol. Monitor therapy

Calcium Channel Blockers (Nondihydropyridine): Protease Inhibitors may decrease the metabolism of Calcium Channel Blockers (Nondihydropyridine). Increased serum concentrations of the calcium channel blocker may increase risk of AV nodal blockade. Management: Avoid concurrent use when possible. If used, monitor for CCB toxicity. The manufacturer of atazanavir recommends a 50% dose reduction for diltiazem be considered. Saquinavir, tipranavir, and darunavir/cobicistat use with bepridil is contraindicated. Consider therapy modification

Canagliflozin: Ritonavir may decrease the serum concentration of Canagliflozin. Management: Consider increasing canagliflozin dose to 200 mg/day in patients tolerating 100 mg/day. A further increase to 300 mg/day can be considered in patients with an estimated glomerular filtration rate (GFR) of 60 mL/min/1.73 m2 or greater. Consider therapy modification

Cannabidiol: CYP3A4 Inhibitors (Strong) may increase the serum concentration of Cannabidiol. Monitor therapy

Cannabis: CYP3A4 Inhibitors (Strong) may increase the serum concentration of Cannabis. More specifically, tetrahydrocannabinol and cannabidiol serum concentrations may be increased. Monitor therapy

Capmatinib: CYP3A4 Inhibitors (Strong) may increase the serum concentration of Capmatinib. Monitor therapy

CarBAMazepine: May decrease the serum concentration of Lopinavir. Lopinavir may increase the serum concentration of CarBAMazepine. Management: Do not use a once daily lopinavir/ritonavir regimen together with carbamazepine. If used with a twice daily lopinavir/ritonavir regimen, monitor for reduced lopinavir/ritonavir effectiveness. Also monitor for increased carbamazepine effects/toxicities. Consider therapy modification

Cariprazine: CYP3A4 Inhibitors (Strong) may increase the serum concentration of Cariprazine. Management: Decrease cariprazine dose 50% (4.5 mg to 1.5 mg or 3 mg; 1.5 mg to 1.5 mg every other day) if starting a strong CYP3A4 inhibitor. If on a strong CYP3A4 inhibitor, start cariprazine at 1.5 mg day 1, 0 mg day 2, then 1.5 mg daily. May increase to 3 mg daily Consider therapy modification

Cat's Claw: May increase the serum concentration of Ritonavir. Monitor therapy

Celiprolol: P-glycoprotein/ABCB1 Inhibitors may increase the serum concentration of Celiprolol. Monitor therapy

Ceritinib: CYP3A4 Inhibitors (Strong) may increase the serum concentration of Ceritinib. Management: If such combinations cannot be avoided, the ceritinib dose should be reduced by approximately one-third (to the nearest 150 mg). Resume the prior ceritinib dose after cessation of the strong CYP3A4 inhibitor. Exceptions discussed in separate monographs. Consider therapy modification

Ciclesonide (Oral Inhalation): CYP3A4 Inhibitors (Strong) may increase serum concentrations of the active metabolite(s) of Ciclesonide (Oral Inhalation). Monitor therapy

Cilostazol: CYP3A4 Inhibitors (Strong) may increase the serum concentration of Cilostazol. Management: Consider reducing the cilostazol dose to 50 mg twice daily in adult patients who are also receiving strong inhibitors of CYP3A4. Consider therapy modification

Cinacalcet: CYP3A4 Inhibitors (Strong) may increase the serum concentration of Cinacalcet. Monitor therapy

Cisapride: Protease Inhibitors may increase the serum concentration of Cisapride. This may result in QTc prolongation and malignant cardiac arrhythmias. Management: Drugs listed as exceptions to this monograph are discussed in further detail in separate drug interaction monographs. Avoid combination

Cladribine: BCRP/ABCG2 Inhibitors may increase the serum concentration of Cladribine. Management: Avoid concomitant use of BCRP inhibitors during the 4 to 5 day oral cladribine treatment cycles whenever possible. If combined, consider dose reduction of the BCRP inhibitor and separation in the timing of administration. Consider therapy modification

Cladribine: Inhibitors of Equilibrative Nucleoside (ENT1) and Concentrative Nucleoside (CNT3) Transport Proteins may increase the serum concentration of Cladribine. Management: Avoid concomitant use of ENT1 or CNT3 inhibitors during the 4 to 5 day oral cladribine treatment cycles whenever possible. If combined, consider an ENT1 or CNT3 inhibitor dose reduction and separation in the timing of administration. Consider therapy modification

Clarithromycin: May enhance the QTc-prolonging effect of Lopinavir. Lopinavir may diminish the therapeutic effect of Clarithromycin. Specifically, lopinavir may decrease the formation of the active 14-hydroxy-clarithromycin metabolite, which may negatively impact clarithromycin effectiveness. Lopinavir may increase the serum concentration of Clarithromycin. Clarithromycin may increase the serum concentration of Lopinavir. Avoid combination

Clobetasone: Ritonavir may increase the serum concentration of Clobetasone. Avoid combination

Clopidogrel: Ritonavir may diminish the antiplatelet effect of Clopidogrel. Ritonavir may decrease serum concentrations of the active metabolite(s) of Clopidogrel. Monitor therapy

Clorazepate: Ritonavir may increase the serum concentration of Clorazepate. Monitor therapy

CloZAPine: CYP3A4 Inhibitors (Strong) may increase the serum concentration of CloZAPine. Management: Drugs listed as exceptions to this monograph are discussed in further detail in separate drug interaction monographs. Monitor therapy

CloZAPine: CYP1A2 Inducers (Weak) may decrease the serum concentration of CloZAPine. Monitor therapy

Cobicistat: May enhance the therapeutic effect of Ritonavir. Specifically, cobicistat and ritonavir have overlapping effects on the CYP3A4-mediated metabolism of other drugs. Avoid combination

Cobimetinib: CYP3A4 Inhibitors (Strong) may increase the serum concentration of Cobimetinib. Avoid combination

Codeine: CYP3A4 Inhibitors (Strong) may increase serum concentrations of the active metabolite(s) of Codeine. Monitor therapy

Colchicine: CYP3A4 Inhibitors (Strong) may increase the serum concentration of Colchicine. Management: Colchicine is contraindicated in patients with impaired renal or hepatic function who are also receiving a strong CYP3A4 inhibitor. In those with normal renal and hepatic function, reduce colchicine dose as directed. See interaction monograph for details. Consider therapy modification

Colchicine: P-glycoprotein/ABCB1 Inhibitors may increase the serum concentration of Colchicine. Colchicine distribution into certain tissues (e.g., brain) may also be increased. Management: Colchicine is contraindicated in patients with impaired renal or hepatic function who are also receiving a P-gp inhibitor. In those with normal renal and hepatic function, reduce colchicine dose as directed. See interaction monograph for details. Consider therapy modification

Conivaptan: CYP3A4 Inhibitors (Strong) may increase the serum concentration of Conivaptan. Avoid combination

Copanlisib: CYP3A4 Inhibitors (Strong) may increase the serum concentration of Copanlisib. Management: If concomitant use of copanlisib and strong CYP3A4 inhibitors cannot be avoided, reduce the copanlisib dose to 45 mg. Monitor patients for increased copanlisib effects/toxicities. Consider therapy modification

Corticosteroids (Systemic): CYP3A4 Inhibitors (Strong) may increase the serum concentration of Corticosteroids (Systemic). Exceptions: MethylPREDNISolone; PrednisoLONE (Systemic); PredniSONE. Monitor therapy

Crizotinib: CYP3A4 Inhibitors (Strong) may increase the serum concentration of Crizotinib. Management: Avoid concomitant use of crizotinib and strong CYP3A4 inhibitors whenever possible. If combined use cannot be avoided, decrease the crizotinib dose to 250 mg daily. Exceptions are discussed in separate monographs. Consider therapy modification

Cyclophosphamide: Protease Inhibitors may enhance the adverse/toxic effect of Cyclophosphamide. Specifically, the incidences of neutropenia, infection, and mucositis may be increased. Monitor therapy

Cyclophosphamide: CYP2B6 Inducers (Moderate) may increase serum concentrations of the active metabolite(s) of Cyclophosphamide. Monitor therapy

CycloSPORINE (Systemic): CYP3A4 Inhibitors (Strong) may increase the serum concentration of CycloSPORINE (Systemic). Management: Monitor cyclosporine serum concentrations and clinical cyclosporine closely with concurrent use of any strong CYP3A4 inhibitor. Cyclosporine dose reductions and/or prolongation of the dosing interval will likely be required. Consider therapy modification

CYP3A4 Inducers (Moderate): May decrease the serum concentration of CYP3A4 Substrates (High risk with Inducers). Monitor therapy

CYP3A4 Inducers (Strong): May increase the metabolism of CYP3A4 Substrates (High risk with Inducers). Management: Consider an alternative for one of the interacting drugs. Some combinations may be specifically contraindicated. Consult appropriate manufacturer labeling. Consider therapy modification

CYP3A4 Substrates (High risk with Inhibitors): CYP3A4 Inhibitors (Strong) may decrease the metabolism of CYP3A4 Substrates (High risk with Inhibitors). Management: Consider avoiding this combination. Some combinations are specifically contraindicated by manufacturers; others may have recommended dose adjustments. If combined, monitor for increased substrate effects. Exceptions: Alitretinoin (Systemic); AmLODIPine; Benzhydrocodone; Bromperidol; Buprenorphine; Gefitinib; HYDROcodone; Mirtazapine; Oliceridine; Praziquantel; Ripretinib; Telithromycin; VinBLAStine; Vinorelbine. Consider therapy modification

Dabrafenib: CYP3A4 Inhibitors (Strong) may increase the serum concentration of Dabrafenib. Avoid combination

Daclatasvir: CYP3A4 Inhibitors (Strong) may increase the serum concentration of Daclatasvir. Management: Decrease the daclatasvir dose to 30 mg once daily if combined with a strong CYP3A4 inhibitor. No dose adjustment is needed when daclatasvir is used with darunavir/cobicistat. Consider therapy modification

Dapoxetine: CYP3A4 Inhibitors (Strong) may increase the serum concentration of Dapoxetine. Avoid combination

Darifenacin: CYP3A4 Inhibitors (Strong) may increase the serum concentration of Darifenacin. Management: Limit the darifenacin dose to no more than 7.5 mg daily if combined with strong CYP3A4 inhibitors. Monitor patients for increased darifenacin toxicities (eg, dry mouth, constipation, headache, CNS effects) when these agents are combined. Consider therapy modification

Darolutamide: Inhibitors of CYP3A4 (Strong) and P-glycoprotein may increase the serum concentration of Darolutamide. Monitor therapy

Darunavir: Lopinavir may decrease the serum concentration of Darunavir. Darunavir may increase the serum concentration of lopinavir Avoid combination

Dasatinib: CYP3A4 Inhibitors (Strong) may increase the serum concentration of Dasatinib. Management: This combination should be avoided if possible. If combined, decrease dasatinib dose from 140 mg to 40 mg, 100 mg to 20 mg, or 70 mg to 20 mg. For patients taking 60 mg or 40 mg daily, stop dasatinib until the CYP3A4 inhibitor is discontinued. Consider therapy modification

Deferasirox: Ritonavir may decrease the serum concentration of Deferasirox. Management: Avoid combination when possible; if the combination must be used, consider a 50% increase in initial deferasirox dose, with monitoring of serum ferritin concentrations and clinical responses to guide further dosing. Consider therapy modification

Deflazacort: CYP3A4 Inhibitors (Strong) may increase serum concentrations of the active metabolite(s) of Deflazacort. Management: Administer one third of the recommended deflazacort dose when used together with a strong or moderate CYP3A4 inhibitor. Consider therapy modification

Delamanid: CYP3A4 Inhibitors (Strong) may increase the serum concentration of Delamanid. Management: Increase ECG monitoring frequency if delamanid is combined with strong CYP3A4 inhibitors due to the risk for QTc interval prolongation. Continue frequent ECG assessments throughout full delamanid treatment period. Exceptions discussed separately. Consider therapy modification

Delavirdine: May increase the serum concentration of Ritonavir. Management: Consider alternatives to this combination. Safe and effective doses for coadministration have not been determined according to lopinavir/ritonavir prescribing information. Consider therapy modification

Delavirdine: May increase the serum concentration of Lopinavir. Management: Consider alternatives to this combination. Safe and effective doses for coadministration have not been determined according to lopinavir/ritonavir prescribing information. Consider therapy modification

DexAMETHasone (Ophthalmic): CYP3A4 Inhibitors (Strong) may increase the serum concentration of DexAMETHasone (Ophthalmic). Monitor therapy

Didanosine: Lopinavir may decrease the serum concentration of Didanosine. This interaction refers only to lopinavir/ritonavir oral solution, which must be taken with food, and is principally the result of a food-didanosine interaction. Management: Didanosine should be administered 1 hour prior to or 2 hours after administration of lopinavir/ritonavir oral solution (which must be taken with food). Didanosine and lopinavir/ritonavir tablets can be administered together. Consider therapy modification

Digitoxin: P-glycoprotein/ABCB1 Inhibitors may increase the serum concentration of Digitoxin. Monitor therapy

Digoxin: Ritonavir may increase the serum concentration of Digoxin. Management: Reduce the digoxin dose by approximately 30% to 50%, or reduce the dosing frequency, when these agents are combined. Monitor digoxin levels closely and adjust digoxin dose as needed. Consider therapy modification

Disulfiram: May enhance the adverse/toxic effect of Products Containing Ethanol. Management: Do not use disulfiram with dosage forms that contain ethanol. Avoid combination

DOCEtaxel: CYP3A4 Inhibitors (Strong) may increase the serum concentration of DOCEtaxel. Management: Avoid the concomitant use of docetaxel and strong CYP3A4 inhibitors when possible. If combined use is unavoidable, consider a 50% docetaxel dose reduction and monitor for increased docetaxel toxicities. Consider therapy modification

Dofetilide: CYP3A4 Inhibitors (Strong) may increase the serum concentration of Dofetilide. Monitor therapy

Domperidone: CYP3A4 Inhibitors (Strong) may increase the serum concentration of Domperidone. Management: Drugs listed as exceptions to this monograph are discussed in further detail in separate drug interaction monographs. Avoid combination

Doxercalciferol: CYP3A4 Inhibitors (Strong) may decrease serum concentrations of the active metabolite(s) of Doxercalciferol. Monitor therapy

DOXOrubicin (Conventional): P-glycoprotein/ABCB1 Inhibitors may increase the serum concentration of DOXOrubicin (Conventional). Avoid combination

Dronabinol: CYP3A4 Inhibitors (Strong) may increase the serum concentration of Dronabinol. Monitor therapy

Dronedarone: CYP3A4 Inhibitors (Strong) may increase the serum concentration of Dronedarone. Management: Drugs listed as exceptions to this monograph are discussed in further detail in separate drug interaction monographs. Avoid combination

Drospirenone: CYP3A4 Inhibitors (Strong) may increase the serum concentration of Drospirenone. Management: Drospirenone use is contraindicated specifically when the strong CYP3A4 inhibitors atazanavir and cobicistat are administered concurrently. Caution should be used when drospirenone is coadministered with other strong CYP3A4 inhibitors. Consider therapy modification

Dutasteride: CYP3A4 Inhibitors (Strong) may increase the serum concentration of Dutasteride. Monitor therapy

Duvelisib: CYP3A4 Inhibitors (Strong) may increase the serum concentration of Duvelisib. Management: Reduce the dose of duvelisib to 15 mg twice a day when used together with a strong CYP3A4 inhibitor. Consider therapy modification

Edoxaban: P-glycoprotein/ABCB1 Inhibitors may increase the serum concentration of Edoxaban. Management: Exceptions to this monograph are discussed in separate Lexi-Interact monographs. Monitor therapy

Efavirenz: May decrease the serum concentration of Lopinavir. Management: Avoid once daily use of lopinavir/ritonavir with efavirenz. Avoid use of this combination in patients less than 6 months of age. See lopinavir/ritonavir prescribing information for specific recommended dose increases in particular patient populations. Consider therapy modification

Elagolix: OATP1B1/1B3 (SLCO1B1/1B3) Inhibitors may increase the serum concentration of Elagolix. Avoid combination

Elagolix, Estradiol, and Norethindrone: OATP1B1/1B3 (SLCO1B1/1B3) Inhibitors may increase the serum concentration of Elagolix, Estradiol, and Norethindrone. Specifically, concentrations of elagolix may be increased. Avoid combination

Elagolix, Estradiol, and Norethindrone: CYP3A4 Inhibitors (Strong) may increase the serum concentration of Elagolix, Estradiol, and Norethindrone. Avoid combination

Eletriptan: CYP3A4 Inhibitors (Strong) may increase the serum concentration of Eletriptan. Avoid combination

Elexacaftor, Tezacaftor, and Ivacaftor: CYP3A4 Inhibitors (Strong) may increase the serum concentration of Elexacaftor, Tezacaftor, and Ivacaftor. Management: When combined with strong CYP3A4 inhibitors, administer two elexacaftor/tezacaftor/ivacaftor tablets (100 mg/50 mg/75 mg) in the morning, twice a week, approximately 3 to 4 days apart. No evening doses of ivacaftor (150 mg) alone should be administered. Consider therapy modification

Eliglustat: CYP3A4 Inhibitors (Strong) may increase the serum concentration of Eliglustat. Management: Reduce eliglustat dose to 84 mg daily in CYP2D6 EMs when used with strong CYP3A4 inhibitors. Use of strong CYP3A4 inhibitors is contraindicated in CYP2D6 IMs, PMs, or in CYP2D6 EMs who are also taking strong or moderate CYP2D6 inhibitors. Consider therapy modification

Eluxadoline: Ritonavir may increase the serum concentration of Eluxadoline. Management: Decrease the eluxadoline dose to 75 mg twice daily if combined with ritonavir and monitor patients for increased eluxadoline effects/toxicities. Consider therapy modification

Elvitegravir: Lopinavir may increase the serum concentration of Elvitegravir. Specifically, lopinavir/ritonavir may increase the concentration of elvitegravir. Management: When elvitegravir is combined with lopinavir/ritonavir, the dose of elvitegravir should be reduced to 85 mg once daily and the dose of lopinavir/ritonavir should be 400 mg/100 mg twice daily. Consider therapy modification

Encorafenib: CYP3A4 Inhibitors (Strong) may increase the serum concentration of Encorafenib. Management: Avoid use of encorafenib and strong CYP3A4 inhibitors when possible. If combined, decrease encorafenib from 450 mg to 150 mg; or from 300 mg, 225 mg, or 150 mg to 75 mg. Once the CYP3A4 inhibitor is discontinued for 3 to 5 half-lives, resume prior dose. Consider therapy modification

Enfortumab Vedotin: CYP3A4 Inhibitors (Strong) may increase the serum concentration of Enfortumab Vedotin. Specifically, concentrations of the active monomethyl auristatin E (MMAE) component may be increased. Monitor therapy

Enfuvirtide: Protease Inhibitors may increase the serum concentration of Enfuvirtide. Enfuvirtide may increase the serum concentration of Protease Inhibitors. Monitor therapy

Entrectinib: CYP3A4 Inhibitors (Strong) may increase the serum concentration of Entrectinib. Management: Avoid strong CYP3A4 inhibitors during treatment with entrectinib when possible. If combined in adults and those 12 yrs of age or older with a BSA of at least 1.5 square meters, reduce dose to 100 mg/day. Avoid if BSA is less than 1.5 square meters. Consider therapy modification

Enzalutamide: May decrease the serum concentration of CYP3A4 Substrates (High risk with Inducers). Management: Concurrent use of enzalutamide with CYP3A4 substrates that have a narrow therapeutic index should be avoided. Use of enzalutamide and any other CYP3A4 substrate should be performed with caution and close monitoring. Consider therapy modification

Eplerenone: CYP3A4 Inhibitors (Strong) may increase the serum concentration of Eplerenone. Avoid combination

Erdafitinib: CYP3A4 Inhibitors (Strong) may increase the serum concentration of Erdafitinib. Management: Avoid concomitant use of erdafitinib and strong CYP3A4 inhibitors when possible. If combined, monitor closely for erdafitinib adverse reactions and consider dose modifications accordingly. Consider therapy modification

Ergot Derivatives: Protease Inhibitors may increase the serum concentration of Ergot Derivatives. Exceptions: Cabergoline; Lisuride; Nicergoline; Pergolide. Avoid combination

Erlotinib: CYP3A4 Inhibitors (Strong) may increase the serum concentration of Erlotinib. Management: Avoid use of this combination when possible. When the combination must be used, monitor the patient closely for the development of severe adverse reactions, and if such severe reactions occur, reduce the erlotinib dose (in 50 mg decrements). Consider therapy modification

Estriol (Systemic): Ritonavir may decrease the serum concentration of Estriol (Systemic). Monitor therapy

Estriol (Topical): Ritonavir may decrease the serum concentration of Estriol (Topical). Monitor therapy

Estrogen Derivatives: CYP3A4 Inhibitors (Strong) may increase the serum concentration of Estrogen Derivatives. Monitor therapy

Estrogen Derivatives (Contraceptive): Protease Inhibitors may decrease the serum concentration of Estrogen Derivatives (Contraceptive). Management: Use oral contraceptives containing at least 35mcg ethinyl estradiol with atazanavir/ritonavir, or no more than 30mcg in patients receiving atazanavir alone. Use of an alternative, non-hormonal contraceptive is recommended with other protease inhibitors. Consider therapy modification

Eszopiclone: CYP3A4 Inhibitors (Strong) may increase the serum concentration of Eszopiclone. Management: Limit the eszopiclone dose to 2 mg daily when combined with strong CYP3A4 inhibitors and monitor for increased eszopiclone effects and toxicities (eg, somnolence, drowsiness, CNS depression). Consider therapy modification

Etizolam: CYP3A4 Inhibitors (Strong) may increase the serum concentration of Etizolam. Management: Consider use of lower etizolam doses when using this combination; specific recommendations concerning dose adjustment are not available. Monitor clinical response to the combination closely. Consider therapy modification

Etoposide: P-glycoprotein/ABCB1 Inhibitors may increase the serum concentration of Etoposide. Monitor therapy

Etoposide Phosphate: P-glycoprotein/ABCB1 Inhibitors may increase the serum concentration of Etoposide Phosphate. Monitor therapy

Etravirine: Ritonavir may decrease the serum concentration of Etravirine. Management: Avoid concomitant use of etravirine with antiviral doses of ritonavir; use with ritonavir-boosted fosamprenavir or with ritonavir-boosted tipranavir is also not recommended. Consider therapy modification

Everolimus: Inhibitors of CYP3A4 (Strong) and P-glycoprotein may increase the serum concentration of Everolimus. Avoid combination

Evogliptin: CYP3A4 Inhibitors (Strong) may increase the serum concentration of Evogliptin. Monitor therapy

Fedratinib: CYP3A4 Inhibitors (Strong) may increase the serum concentration of Fedratinib. Management: Consider alternatives when possible. If used together, decrease fedratinib dose to 200 mg/day. After the inhibitor is stopped, increase fedratinib to 300 mg/day for the first 2 weeks and then to 400 mg/day as tolerated. Consider therapy modification

FentaNYL: CYP3A4 Inhibitors (Strong) may increase the serum concentration of FentaNYL. Management: Consider fentanyl dose reductions when combined with a strong CYP3A4 inhibitor. Monitor for respiratory depression and sedation. Upon discontinuation of a CYP3A4 inhibitor, consider a fentanyl dose increase; monitor for signs and symptoms of withdrawal. Consider therapy modification

Fesoterodine: CYP3A4 Inhibitors (Strong) may increase serum concentrations of the active metabolite(s) of Fesoterodine. Management: Limit fesoterodine doses to 4 mg daily in patients who are also receiving strong CYP3A4 inhibitors. Consider therapy modification

Flecainide: Ritonavir may increase the serum concentration of Flecainide. Avoid combination

Flibanserin: CYP3A4 Inhibitors (Strong) may increase the serum concentration of Flibanserin. Management: Use of flibanserin with strong CYP3A4 inhibitors is contraindicated. If starting flibanserin, start 2 weeks after the last dose of the CYP3A4 inhibitor. If starting a CYP3A4 inhibitor, start 2 days after the last dose of flibanserin. Avoid combination

Fluticasone (Nasal): CYP3A4 Inhibitors (Strong) may increase the serum concentration of Fluticasone (Nasal). Avoid combination

Fluticasone (Oral Inhalation): CYP3A4 Inhibitors (Strong) may increase the serum concentration of Fluticasone (Oral Inhalation). Consider therapy modification

Fosamprenavir: May decrease the serum concentration of Lopinavir. Specifically, amprenavir (the active metabolite of fosamprenavir) may decrease the serum concentration of lopinavir. Lopinavir may decrease the serum concentration of Fosamprenavir. Specifically, lopinavir/ritonavir may decrease the serum concentration of amprenavir (the active metabolite of fosamprenavir) Avoid combination

Fosaprepitant: CYP3A4 Inhibitors (Strong) may increase the serum concentration of Fosaprepitant. Avoid combination

Fosphenytoin: May decrease the serum concentration of Lopinavir. Lopinavir may decrease the serum concentration of Fosphenytoin. Management: The manufacturer of lopinavir/ritonavir recommends avoiding once-daily administration if used together with phenytoin. Consider therapy modification

Fosphenytoin: May decrease the serum concentration of Ritonavir. Ritonavir may decrease the serum concentration of Fosphenytoin. Management: Dose adjustments may be required. Monitor phenytoin concentrations, and for therapeutic reponse to fosphenytoin and ritonavir, particularly with any dose adjustments. Consider therapy modification

Fostamatinib: CYP3A4 Inhibitors (Strong) may increase serum concentrations of the active metabolite(s) of Fostamatinib. Monitor therapy

Fusidic Acid (Systemic): Ritonavir may increase the serum concentration of Fusidic Acid (Systemic). Fusidic Acid (Systemic) may increase the serum concentration of Ritonavir. Avoid combination

Galantamine: CYP3A4 Inhibitors (Strong) may increase the serum concentration of Galantamine. Monitor therapy

Garlic: May decrease the serum concentration of Protease Inhibitors. Management: Concurrent use of garlic supplements with protease inhibitors is not recommended. If this combination is used, monitor closely for altered serum concentrations/effects of protease inhibitors, and particularly for signs/symptoms of therapeutic failure. Consider therapy modification

Gefitinib: CYP3A4 Inhibitors (Strong) may increase the serum concentration of Gefitinib. Monitor therapy

Gilteritinib: CYP3A4 Inhibitors (Strong) may increase the serum concentration of Gilteritinib. Management: Consider alternatives to the use of a strong CYP3A4 inhibitor with gilteritinib. If the combination cannot be avoided, monitor more closely for evidence of gilteritinib toxicities. Consider therapy modification

Glasdegib: CYP3A4 Inhibitors (Strong) may increase the serum concentration of Glasdegib. Management: Consider alternatives to this combination when possible. If the combination must be used, monitor closely for evidence of QT interval prolongation and other adverse reactions to glasdegib. Consider therapy modification

Glecaprevir and Pibrentasvir: Lopinavir may increase the serum concentration of Glecaprevir and Pibrentasvir. Avoid combination

Glecaprevir and Pibrentasvir: Ritonavir may increase the serum concentration of Glecaprevir and Pibrentasvir. Avoid combination

Grazoprevir: Lopinavir may increase the serum concentration of Grazoprevir. Avoid combination

GuanFACINE: CYP3A4 Inhibitors (Strong) may increase the serum concentration of GuanFACINE. Management: Reduce the extended-release guanfacine dose 50% when combined with a strong CYP3A4 inhibitor. Monitor for increased guanfacine toxicities when these agents are combined. Consider therapy modification

Halofantrine: CYP3A4 Inhibitors (Strong) may increase the serum concentration of Halofantrine. Management: Drugs listed as exceptions to this monograph are discussed in further detail in separate drug interaction monographs. Avoid combination

HYDROcodone: CYP3A4 Inhibitors (Strong) may increase the serum concentration of HYDROcodone. Monitor therapy

Ibrutinib: CYP3A4 Inhibitors (Strong) may increase the serum concentration of Ibrutinib. Management: Avoid concomitant use of ibrutinib and strong CYP3A4 inhibitors. If a strong CYP3A4 inhibitor must be used short-term (eg, anti-infectives for 7 days or less), interrupt ibrutinib therapy until the strong CYP3A4 inhibitor is discontinued. Avoid combination

Idelalisib: CYP3A4 Inhibitors (Strong) may increase the serum concentration of Idelalisib. Monitor therapy

Ifosfamide: CYP3A4 Inhibitors (Strong) may decrease serum concentrations of the active metabolite(s) of Ifosfamide. Monitor therapy

Iloperidone: CYP3A4 Inhibitors (Strong) may increase serum concentrations of the active metabolite(s) of Iloperidone. Specifically, concentrations of the metabolites P88 and P95 may be increased. CYP3A4 Inhibitors (Strong) may increase the serum concentration of Iloperidone. Management: Reduce iloperidone dose by half when administered with a strong CYP3A4 inhibitor. Consider therapy modification

Imatinib: CYP3A4 Inhibitors (Strong) may increase the serum concentration of Imatinib. Monitor therapy

Imidafenacin: CYP3A4 Inhibitors (Strong) may increase the serum concentration of Imidafenacin. Monitor therapy

Irinotecan Products: CYP3A4 Inhibitors (Strong) may increase serum concentrations of the active metabolite(s) of Irinotecan Products. Specifically, serum concentrations of SN-38 may be increased. CYP3A4 Inhibitors (Strong) may increase the serum concentration of Irinotecan Products. Avoid combination

Isavuconazonium Sulfate: CYP3A4 Inhibitors (Strong) may increase serum concentrations of the active metabolite(s) of Isavuconazonium Sulfate. Specifically, CYP3A4 Inhibitors (Strong) may increase isavuconazole serum concentrations. Management: Combined use is considered contraindicated per US labeling. Lopinavir/ritonavir (and possibly other uses of ritonavir doses less than 400 mg every 12 hours) is treated as a possible exception to this contraindication despite strongly inhibiting CYP3A4. Avoid combination

Istradefylline: CYP3A4 Inhibitors (Strong) may increase the serum concentration of Istradefylline. Management: Limit the maximum istradefylline dose to 20 mg daily when combined with strong CYP3A4 inhibitors and monitor for increased istradefylline effects/toxicities. Consider therapy modification

Itraconazole: Lopinavir may increase the serum concentration of Itraconazole. Management: Limit the adult maximum itraconazole dose to 200 mg/day in patients receiving lopinavir/ritonavir. Consider therapy modification

Itraconazole: Ritonavir may increase the serum concentration of Itraconazole. Management: Limit the adult maximum itraconazole dose to 200 mg/day in patients receiving ritonavir. Consider therapy modification

Ivabradine: CYP3A4 Inhibitors (Strong) may increase the serum concentration of Ivabradine. Avoid combination

Ivacaftor: CYP3A4 Inhibitors (Strong) may increase the serum concentration of Ivacaftor. Management: Ivacaftor dose reductions are required; consult full drug interaction monograph content for age- and weight-specific recommendations. Consider therapy modification

Ivosidenib: CYP3A4 Inhibitors (Strong) may increase the serum concentration of Ivosidenib. Management: Avoid use of a strong CYP3A4 inhibitor with ivosidenib whenever possible. When combined use is required, reduce the ivosidenib dose to 250 mg once daily. Drugs listed as exceptions are discussed in further detail in separate drug interaction monographs. Consider therapy modification

Ixabepilone: CYP3A4 Inhibitors (Strong) may increase the serum concentration of Ixabepilone. Management: Avoid use of ixabepilone and strong CYP3A4 inhibitors when possible. If combined, reduce the ixabepilone dose to 20 mg/m2. The previous ixabepilone dose can be resumed 1 week after discontinuation of the strong CYP3A4 inhibitor. Consider therapy modification

Ketoconazole (Systemic): May increase the serum concentration of Lopinavir. Lopinavir may increase the serum concentration of Ketoconazole (Systemic). Management: Limit the adult maximum ketoconazole dose to 200 mg/day in patients receiving lopinavir/ritonavir. Consider therapy modification

Ketoconazole (Systemic): Ritonavir may increase the serum concentration of Ketoconazole (Systemic). Management: Limit the adult maximum ketoconazole dose to 200 mg/day in patients receiving ritonavir. Consider therapy modification

LamoTRIgine: Lopinavir may decrease the serum concentration of LamoTRIgine. Management: For patients taking lopinavir/ritonavir without valproate, lamotrigine dose adjustments are recommended for lamotrigine initiation. Recommendations vary based on lamotrigine indication and age. See full interact monograph for details. Consider therapy modification

Lapatinib: CYP3A4 Inhibitors (Strong) may increase the serum concentration of Lapatinib. Management: Avoid use of lapatinib and strong CYP3A4 inhibitors when possible. If combined, reduce lapatinib dose to 500 mg daily. The previous lapatinib dose can be resumed 1 week after discontinuation of the strong CYP3A4 inhibitor. Consider therapy modification

Larotrectinib: CYP3A4 Inhibitors (Strong) may increase the serum concentration of Larotrectinib. Management: Avoid use of strong CYP3A4 inhibitors with larotrectinib. If this combination cannot be avoided, reduce the larotrectinib dose by 50%. Increase to previous dose after stopping the inhibitor after a period of 3 to 5 times the inhibitor's half-life. Consider therapy modification

Lefamulin: CYP3A4 Inhibitors (Strong) may increase the serum concentration of Lefamulin. Management: Avoid concomitant use of lefamulin tablets and strong inhibitors of CYP3A4. Avoid combination

Lemborexant: CYP3A4 Inhibitors (Strong) may increase the serum concentration of Lemborexant. Avoid combination

Lercanidipine: CYP3A4 Inhibitors (Strong) may increase the serum concentration of Lercanidipine. Avoid combination

Letermovir: May increase the serum concentration of UGT1A1 Inducers. Avoid combination

Levamlodipine: CYP3A4 Inhibitors (Strong) may increase the serum concentration of Levamlodipine. Monitor therapy

Levobupivacaine: CYP3A4 Inhibitors (Strong) may increase the serum concentration of Levobupivacaine. Monitor therapy

Levomethadone: Lopinavir may decrease the serum concentration of Levomethadone. Monitor therapy

Levomethadone: Ritonavir may decrease the serum concentration of Levomethadone. Monitor therapy

Levomilnacipran: CYP3A4 Inhibitors (Strong) may increase the serum concentration of Levomilnacipran. Management: Do not exceed a maximum adult levomilnacipran dose of 80 mg/day in patients also receiving strong CYP3A4 inhibitors. Consider therapy modification

LinaGLIPtin: Ritonavir may increase the serum concentration of LinaGLIPtin. Monitor therapy

Lomitapide: CYP3A4 Inhibitors (Strong) may increase the serum concentration of Lomitapide. Avoid combination

Lorlatinib: CYP3A4 Inhibitors (Strong) may increase the serum concentration of Lorlatinib. Management: Avoid use of lorlatinib with strong CYP3A4 inhibitors. If the combination cannot be avoided, reduce the lorlatinib dose from 100 mg once daily to 75 mg once daily, or from 75 mg once daily to 50 mg once daily. Consider therapy modification

Lovastatin: Protease Inhibitors may increase the serum concentration of Lovastatin. Avoid combination

Lovastatin: CYP3A4 Inhibitors (Strong) may increase the serum concentration of Lovastatin. Avoid combination

Lumacaftor and Ivacaftor: CYP3A4 Inhibitors (Strong) may increase the serum concentration of Lumacaftor and Ivacaftor. Management: When initiating or resuming lumacaftor/ivacaftor after a therapy interruption of 7 days or more, reduce the lumacaftor/ivacaftor dose to 1 tablet daily or 1 packet of oral granules every other day for the first week, and then resume the standard dose. Consider therapy modification

Lumateperone: CYP3A4 Inhibitors (Strong) may increase the serum concentration of Lumateperone. Avoid combination

Lumefantrine: CYP3A4 Inhibitors (Strong) may increase the serum concentration of Lumefantrine. Monitor therapy

Lurasidone: CYP3A4 Inhibitors (Strong) may increase the serum concentration of Lurasidone. Avoid combination

Lurbinectedin: CYP3A4 Inhibitors (Strong) may increase the serum concentration of Lurbinectedin. Avoid combination

Macitentan: CYP3A4 Inhibitors (Strong) may increase the serum concentration of Macitentan. Avoid combination

Manidipine: CYP3A4 Inhibitors (Strong) may increase the serum concentration of Manidipine. Management: Consider avoiding concomitant use of manidipine and strong CYP3A4 inhibitors. If combined, monitor closely for increased manidipine effects and toxicities. Manidipine dose reductions may be required. Consider therapy modification

Maraviroc: CYP3A4 Inhibitors (Strong) may increase the serum concentration of Maraviroc. Management: Reduce maraviroc to 150mg twice/day in adult and pediatric patients weighing 40kg or more. See full interaction monograph or maraviroc labeling for dose adjustments in pediatric patients less than 40kg. Do not use in patients with CrCl less than 30mL/min. Consider therapy modification

Mebendazole: Ritonavir may decrease the serum concentration of Mebendazole. Monitor therapy

Meperidine: CYP3A4 Inhibitors (Strong) may increase the serum concentration of Meperidine. Monitor therapy

Meptazinol: Ritonavir may increase the serum concentration of Meptazinol. Avoid combination

Methadone: Lopinavir may enhance the QTc-prolonging effect of Methadone. Lopinavir may decrease the serum concentration of Methadone. More specifically, the combination of Lopinavir and Ritonavir may decrease Methadone serum concentrations. Monitor therapy

Methadone: Ritonavir may decrease the serum concentration of Methadone. Monitor therapy

Methotrimeprazine: Products Containing Ethanol may enhance the adverse/toxic effect of Methotrimeprazine. Specifically, CNS depressant effects may be increased. Management: Avoid products containing alcohol in patients treated with methotrimeprazine. Avoid combination

MethylPREDNISolone: CYP3A4 Inhibitors (Strong) may increase the serum concentration of MethylPREDNISolone. Management: Consider methylprednisolone dose reduction in patients receiving strong CYP3A4 inhibitors and monitor for increased steroid related adverse effects. Consider therapy modification

MetroNIDAZOLE (Systemic): Ritonavir may enhance the adverse/toxic effect of MetroNIDAZOLE (Systemic). Specifically, the combination of ritonavir oral solution or ritonavir soft gelatin capsule, both of which contain alcohol, and metronidazole may result in a disulfiram-like reaction. Avoid combination

MetroNIDAZOLE (Topical): May enhance the adverse/toxic effect of Lopinavir. Specifically, the use of topical metronidazole with lopinavir/ritonavir solution (which contains 42% alcohol) may result in a disulfiram-like reaction. Monitor therapy

Midazolam: Protease Inhibitors may increase the serum concentration of Midazolam. Management: Oral midazolam contraindicated with all protease inhibitors. IV midazolam contraindicated with fosamprenavir and nelfinavir; other protease inhibitors recommend caution, close monitoring, and consideration of lower IV midazolam doses with concurrent use. Avoid combination

Midostaurin: CYP3A4 Inhibitors (Strong) may increase the serum concentration of Midostaurin. Management: Seek alternatives to the concomitant use of midostaurin and strong CYP3A4 inhibitors if possible. If concomitant use cannot be avoided, monitor patients for increased risk of adverse reactions. Exceptions are discussed in separate monographs. Consider therapy modification

MiFEPRIStone: CYP3A4 Inhibitors (Strong) may increase the serum concentration of MiFEPRIStone. Management: For treatment of hyperglycemia in Cushing's syndrome, start mifepristone at 300 mg/day, may titrate to a maximum of 900 mg/day. If starting a strong CYP3A4 inhibitor and taking >300 mg/day mifepristone, decrease the mifepristone dose by 300 mg/day. Consider therapy modification

Mirodenafil: CYP3A4 Inhibitors (Strong) may increase the serum concentration of Mirodenafil. Management: Consider using a lower dose of mirodenafil when used with strong CYP3A4 inhibitors. Monitor for increased mirodenafil effects/toxicities with the use of this combination. Consider therapy modification

Mirtazapine: CYP3A4 Inhibitors (Strong) may increase the serum concentration of Mirtazapine. Monitor therapy

Mitotane: May decrease the serum concentration of CYP3A4 Substrates (High risk with Inducers). Management: Doses of CYP3A4 substrates may need to be adjusted substantially when used in patients being treated with mitotane. Consider therapy modification

Mometasone (Oral Inhalation): CYP3A4 Inhibitors (Strong) may increase the serum concentration of Mometasone (Oral Inhalation). Monitor therapy

Morphine (Systemic): P-glycoprotein/ABCB1 Inhibitors may increase the serum concentration of Morphine (Systemic). Monitor therapy

Nadolol: P-glycoprotein/ABCB1 Inhibitors may increase the serum concentration of Nadolol. Monitor therapy

Naldemedine: CYP3A4 Inhibitors (Strong) may increase the serum concentration of Naldemedine. Monitor therapy

Nalfurafine: CYP3A4 Inhibitors (Strong) may increase the serum concentration of Nalfurafine. Monitor therapy

Naloxegol: CYP3A4 Inhibitors (Strong) may increase the serum concentration of Naloxegol. Avoid combination

Nefazodone: Protease Inhibitors may increase the serum concentration of Nefazodone. Management: Consider alternatives to, or reduced doses of, nefazodone in patients treated with HIV protease inhibitors. Monitor patients receiving these combinations closely for toxic effects of nefazodone. Consider therapy modification

Nelfinavir: May decrease the serum concentration of Lopinavir. Lopinavir may increase the serum concentration of Nelfinavir. Concentrations of the nelfinavir M8 metabolite may also be increased. Management: Avoid once daily use of lopinavir/ritonavir with nelfinavir. Avoid use of this combination in patients less than 6 months of age. See lopinavir/ritonavir prescribing information for recommended dose increases in other patients. Consider therapy modification

Neratinib: CYP3A4 Inhibitors (Strong) may increase the serum concentration of Neratinib. Avoid combination

Nevirapine: May decrease the serum concentration of Lopinavir. Management: Avoid once daily use of lopinavir/ritonavir with nevirapine. Avoid use of this combination in patients less than 6 months of age. See lopinavir/ritonavir prescribing information for recommended dose increases in other patients. Consider therapy modification

Nilotinib: CYP3A4 Inhibitors (Strong) may increase the serum concentration of Nilotinib. Management: Avoid if possible. If combination needed, decrease nilotinib to 300 mg once/day for patients with resistant or intolerant Ph+ CML or to 200 mg once/day for patients with newly diagnosed Ph+ CML in chronic phase. Exceptions discussed in separate monograph. Consider therapy modification

NiMODipine: CYP3A4 Inhibitors (Strong) may increase the serum concentration of NiMODipine. Avoid combination

Nintedanib: Inhibitors of CYP3A4 (Strong) and P-glycoprotein may increase the serum concentration of Nintedanib. Monitor therapy

Nisoldipine: CYP3A4 Inhibitors (Strong) may increase the serum concentration of Nisoldipine. Avoid combination

OLANZapine: Ritonavir may decrease the serum concentration of OLANZapine. Monitor therapy

Olaparib: CYP3A4 Inhibitors (Strong) may increase the serum concentration of Olaparib. Management: Avoid use of strong CYP3A4 inhibitors with olaparib, if possible. If such concurrent use cannot be avoided, the dose of olaparib tablets should be reduced to 100 mg twice daily and the dose of olaparib capsules should be reduced to 150 mg twice daily. Consider therapy modification

Oliceridine: CYP3A4 Inhibitors (Strong) may increase the serum concentration of Oliceridine. Monitor therapy

Orlistat: May decrease the serum concentration of Antiretroviral Agents. Monitor therapy

Osilodrostat: CYP3A4 Inhibitors (Strong) may increase the serum concentration of Osilodrostat. Management: Reduce osilodrostat dose by 50% during coadministration with a strong CYP3A4 inhibitor. Consider therapy modification

Ospemifene: CYP3A4 Inhibitors (Strong) may increase the serum concentration of Ospemifene. Monitor therapy

Oxybutynin: CYP3A4 Inhibitors (Strong) may increase the serum concentration of Oxybutynin. Monitor therapy

Ozanimod: BCRP/ABCG2 Inhibitors may increase serum concentrations of the active metabolite(s) of Ozanimod. Avoid combination

Palbociclib: CYP3A4 Inhibitors (Strong) may increase the serum concentration of Palbociclib. Management: Avoid concurrent use of strong CYP3A4 inhibitors with palbociclib when possible. If the use of a strong CYP3A4 inhibitor cannot be avoided, decrease the palbociclib dose to 75 mg/day. Consider therapy modification

Panobinostat: CYP3A4 Inhibitors (Strong) may increase the serum concentration of Panobinostat. Management: Reduce the panobinostat dose to 10 mg when it must be used with a strong CYP3A4 inhibitor. Consider therapy modification

Parecoxib: CYP3A4 Inhibitors (Strong) may increase the serum concentration of Parecoxib. Specifically, serum concentrations of the active moiety valdecoxib may be increased. Monitor therapy

Paricalcitol: CYP3A4 Inhibitors (Strong) may increase the serum concentration of Paricalcitol. Monitor therapy

PAZOPanib: P-glycoprotein/ABCB1 Inhibitors may increase the serum concentration of PAZOPanib. Avoid combination

PAZOPanib: BCRP/ABCG2 Inhibitors may increase the serum concentration of PAZOPanib. Avoid combination

Pemigatinib: CYP3A4 Inhibitors (Strong) may increase the serum concentration of Pemigatinib. Management: If combined use cannot be avoided, reduce the pemigatinib dose from 13.5 mg daily to 9 mg daily, or from 9 mg daily to 4.5 mg daily. Resume prior pemigatinib dose after stopping the strong inhibitor once 3 half-lives of the inhibitor has passed. Consider therapy modification

Pexidartinib: CYP3A4 Inhibitors (Strong) may increase the serum concentration of Pexidartinib. Management: Avoid use of pexidartinib with strong CYP3A4 inhibitors if possible. If combined use cannot be avoided, pexidartinib dose should be reduced. Decrease 800 mg or 600 mg daily doses to 200 mg twice daily. Decrease doses of 400 mg per day to 200 mg once daily Consider therapy modification

PHENobarbital: May decrease the serum concentration of Lopinavir. Management: Increased doses of lopinavir may be necessary when using these agents in combination. Do not use a once daily lopinavir/ritonavir regimen together with phenobarbital. Increase monitoring of therapeutic response in all patients using this combination. Consider therapy modification

Phenytoin: May decrease the serum concentration of Lopinavir. Lopinavir may decrease the serum concentration of Phenytoin. Management: The manufacturer of lopinavir/ritonavir recommends avoiding once-daily administration if used together with phenytoin. Consider therapy modification

Phenytoin: May decrease the serum concentration of Ritonavir. Ritonavir may decrease the serum concentration of Phenytoin. Management: Dose adjustments may be required. Monitor phenytoin concentrations, and for therapeutic reponse to phenytoin and ritonavir, particularly with any dose adjustments. Consider therapy modification

Pimavanserin: CYP3A4 Inhibitors (Strong) may increase the serum concentration of Pimavanserin. Management: Decrease the pimavanserin dose to 10 mg daily when combined with strong CYP3A4 inhibitors. Consider therapy modification

Pimecrolimus: CYP3A4 Inhibitors (Strong) may decrease the metabolism of Pimecrolimus. Monitor therapy

Pimozide: Protease Inhibitors may increase the serum concentration of Pimozide. Avoid combination

Pimozide: CYP3A4 Inhibitors (Strong) may increase the serum concentration of Pimozide. Avoid combination

Piperaquine: CYP3A4 Inhibitors (Strong) may enhance the QTc-prolonging effect of Piperaquine. CYP3A4 Inhibitors (Strong) may increase the serum concentration of Piperaquine. Management: Avoid concomitant use of piperaquine and strong CYP3A4 inhibitors when possible. If the combination cannot be avoided, frequent ECG monitoring is recommended due to the risk for QTc prolongation. Exceptions are discussed separately. Consider therapy modification

Polatuzumab Vedotin: CYP3A4 Inhibitors (Strong) may increase the serum concentration of Polatuzumab Vedotin. Exposure to unconjugated MMAE, the cytotoxic small molecule component of polatuzumab vedotin, may be increased. Monitor therapy

PONATinib: CYP3A4 Inhibitors (Strong) may increase the serum concentration of PONATinib. Management: Per ponatinib U.S. prescribing information, the adult starting dose of ponatinib should be reduced to 30 mg daily during treatment with any strong CYP3A4 inhibitor. Consider therapy modification

Posaconazole: May increase the serum concentration of Ritonavir. Monitor therapy

Pralsetinib: CYP3A4 Inhibitors (Strong) may increase the serum concentration of Pralsetinib. Avoid combination

Pranlukast: CYP3A4 Inhibitors (Strong) may increase the serum concentration of Pranlukast. Monitor therapy

Praziquantel: CYP3A4 Inhibitors (Strong) may increase the serum concentration of Praziquantel. Monitor therapy

PrednisoLONE (Systemic): Ritonavir may increase the serum concentration of PrednisoLONE (Systemic). Management: Consider prednisolone dose reductions in patients receiving ritonavir and monitor for increased adverse effects with concomitant use. Consider therapy modification

PredniSONE: Ritonavir may increase the serum concentration of PredniSONE. Monitor therapy

Progestins (Contraceptive): Lopinavir may decrease the serum concentration of Progestins (Contraceptive). Lopinavir may increase the serum concentration of Progestins (Contraceptive). Management: Consider using an alternative or additional means of contraception. Injected depot medroxyprogesterone acetate and etonogestrel implants may be used without a need for additional contraception. Exceptions: Levonorgestrel (IUD). Consider therapy modification

Proguanil: Ritonavir may decrease the serum concentration of Proguanil. Monitor therapy

Propafenone: Ritonavir may increase the serum concentration of Propafenone. Avoid combination

Protease Inhibitors: May increase the serum concentration of other Protease Inhibitors. Management: Atazanavir--indinavir combination contraindicated. Tipranavir/ritonavir or atazanavir/ritonavir not recommended with other protease inhibitors (PI). Darunavir/cobicistat not recommended with PI that require boosting.Other combos may require dose changes. Consider therapy modification

QT-prolonging Agents (Highest Risk): QT-prolonging Agents (Indeterminate Risk - Avoid) may enhance the QTc-prolonging effect of QT-prolonging Agents (Highest Risk). Management: Monitor for QTc interval prolongation and ventricular arrhythmias when these agents are combined. Patients with additional risk factors for QTc prolongation may be at even higher risk. Monitor therapy

QUEtiapine: Ritonavir may increase the serum concentration of QUEtiapine. Management: The ritonavir Canadian labeling states this combination should not be used. U.S. labeling recommends using an alternative when possible; if the combination must be used, quetiapine dose reductions are needed. Consider therapy modification

QuiNIDine: Ritonavir may increase the serum concentration of QuiNIDine. Avoid combination

QuiNIDine: Lopinavir may enhance the QTc-prolonging effect of QuiNIDine. Lopinavir may increase the serum concentration of QuiNIDine. Specifically, lopinavir/ritonavir may increase the serum concentration of quinidine. Avoid combination

QuiNINE: Ritonavir may decrease the serum concentration of QuiNINE. This effect has been seen with lopinavir/ritonavir. The individual contributions of lopinavir and ritonavir to this effect are unclear. QuiNINE may increase the serum concentration of Ritonavir. Ritonavir may increase the serum concentration of QuiNINE. Avoid combination

QuiNINE: Lopinavir may decrease the serum concentration of QuiNINE. This effect has been seen with lopinavir/ritonavir. The individual contributions of lopinavir and ritonavir to this effect are unclear. Avoid combination

Radotinib: CYP3A4 Inhibitors (Strong) may increase the serum concentration of Radotinib. Avoid combination

Ramelteon: CYP3A4 Inhibitors (Strong) may increase the serum concentration of Ramelteon. Monitor therapy

Ranolazine: CYP3A4 Inhibitors (Strong) may increase the serum concentration of Ranolazine. Avoid combination

Red Yeast Rice: CYP3A4 Inhibitors (Strong) may increase the serum concentration of Red Yeast Rice. Specifically, concentrations of lovastatin and related compounds found in Red Yeast Rice may be increased. Avoid combination

Regorafenib: CYP3A4 Inhibitors (Strong) may increase the serum concentration of Regorafenib. Avoid combination

Repaglinide: CYP3A4 Inhibitors (Strong) may increase the serum concentration of Repaglinide. Management: The addition of a CYP2C8 inhibitor to this drug combination may substantially increase the magnitude of increase in repaglinide exposure. Monitor therapy

Retapamulin: CYP3A4 Inhibitors (Strong) may increase the serum concentration of Retapamulin. Management: Avoid this combination in patients less than 2 years old. No action is required in other populations. Monitor therapy

Revefenacin: OATP1B1/1B3 (SLCO1B1/1B3) Inhibitors may increase serum concentrations of the active metabolite(s) of Revefenacin. Avoid combination

Ribociclib: CYP3A4 Inhibitors (Strong) may increase the serum concentration of Ribociclib. Management: Avoid use of ribociclib with strong CYP3A4 inhibitors when possible; if combined use cannot be avoided, reduce ribociclib dose to 400 mg once daily. Exceptions are discussed in separate monographs. Consider therapy modification

Rifabutin: Lopinavir may increase serum concentrations of the active metabolite(s) of Rifabutin. Lopinavir may increase the serum concentration of Rifabutin. Management: Reduce rifabutin doses. Clinical guidelines recommend 150 mg daily. Lopinavir/ritonavir prescribing information recommends a decrease of at least 75% (ie, to 150 mg every other day or 3 times per week). Consider therapy modification

Rifabutin: Ritonavir may increase serum concentrations of the active metabolite(s) of Rifabutin. Ritonavir may increase the serum concentration of Rifabutin. Management: Ritonavir US prescribing information recommends reducing rifabutin doses by at least 75%. Refer to drug interaction monographs addressing concomitantly administered protease inhibitors for dosing recommendations specific to ritonavir-boosted regimens. Consider therapy modification

RifAMPin: May enhance the adverse/toxic effect of Lopinavir. Specifically, the risk of hepatocellular toxicity may be increased. RifAMPin may decrease the serum concentration of Lopinavir. Avoid combination

RifAMPin: May decrease the serum concentration of Ritonavir. Avoid combination

RifAXIMin: P-glycoprotein/ABCB1 Inhibitors may increase the serum concentration of RifAXIMin. Monitor therapy

Rilpivirine: Lopinavir may increase the serum concentration of Rilpivirine. Monitor therapy

Rimegepant: CYP3A4 Inhibitors (Strong) may increase the serum concentration of Rimegepant. Avoid combination

Rimegepant: BCRP/ABCG2 Inhibitors may increase the serum concentration of Rimegepant. Avoid combination

Riociguat: Inhibitors of CYP3A4 (Strong) and P-glycoprotein may increase the serum concentration of Riociguat. Management: Consider a riociguat starting dose of 0.5 mg 3 times a day when initiating riociguat in patients receiving strong CYP3A4 and P-gp inhibitors. Monitor for hypotension when these agents are combined and reduce the riociguat dose as needed. Consider therapy modification

Riociguat: Inhibitors of CYP3A4 (Strong) and BCRP may increase the serum concentration of Riociguat. Management: Consider a riociguat starting dose of 0.5 mg 3 times a day when initiating riociguat in patients receiving strong CYP3A4 and BCRP inhibitors. Monitor for hypotension when these agents are combined and reduce the riociguat dose as needed. Consider therapy modification

Ripretinib: CYP3A4 Inhibitors (Strong) may increase the serum concentration of Ripretinib. Monitor therapy

RisperiDONE: P-glycoprotein/ABCB1 Inhibitors may increase the serum concentration of RisperiDONE. Monitor therapy

Rivaroxaban: Inhibitors of CYP3A4 (Strong) and P-glycoprotein may increase the serum concentration of Rivaroxaban. Avoid combination

RomiDEPsin: CYP3A4 Inhibitors (Strong) may increase the serum concentration of RomiDEPsin. Monitor therapy

RomiDEPsin: P-glycoprotein/ABCB1 Inhibitors may increase the serum concentration of RomiDEPsin. Monitor therapy

Rosuvastatin: Protease Inhibitors may increase the serum concentration of Rosuvastatin. Management: Limit rosuvastatin to 5 mg daily in patients receiving atazanavir/ritonavir or lopinavir/ritonavir. Patients receiving fosamprenavir/ritonavir or tipranavir/ritonavir do require dose adjustments if rosuvastatin is used concomitantly. Consider therapy modification

Rupatadine: CYP3A4 Inhibitors (Strong) may increase the serum concentration of Rupatadine. Avoid combination

Ruxolitinib: CYP3A4 Inhibitors (Strong) may increase the serum concentration of Ruxolitinib. Management: This combination should be avoided under some circumstances. See monograph for details. Consider therapy modification

Sacituzumab Govitecan: UGT1A1 Inducers may decrease serum concentrations of the active metabolite(s) of Sacituzumab Govitecan. Specifically, concentrations of SN-38 may be decreased. Avoid combination

Salmeterol: CYP3A4 Inhibitors (Strong) may increase the serum concentration of Salmeterol. Avoid combination

Sarilumab: May decrease the serum concentration of CYP3A4 Substrates (High risk with Inducers). Monitor therapy

SAXagliptin: CYP3A4 Inhibitors (Strong) may increase the serum concentration of SAXagliptin. Management: Limit the saxagliptin dose to 2.5 mg daily when combined with strong CYP3A4 inhibitors. When using the saxagliptin combination products saxagliptin/dapagliflozin or saxagliptin/dapagliflozin/metformin, avoid use with strong CYP3A4 inhibitors. Consider therapy modification

Selpercatinib: CYP3A4 Inhibitors (Strong) may increase the serum concentration of Selpercatinib. Management: Avoid combination if possible. If use is necessary, reduce selpercatinib dose as follows: from 120 mg twice/day to 40 mg twice/day, or from 160 mg twice/day to 80 mg twice/day. Consider therapy modification

Selumetinib: CYP3A4 Inhibitors (Strong) may increase the serum concentration of Selumetinib. Management: Avoid concomitant use when possible. If combined, selumetinib dose reductions are recommended and vary based on body surface area and selumetinib dose. For details, see the full drug interaction monograph or selumetinib prescribing information. Consider therapy modification

Sibutramine: CYP3A4 Inhibitors (Strong) may increase serum concentrations of the active metabolite(s) of Sibutramine. CYP3A4 Inhibitors (Strong) may increase the serum concentration of Sibutramine. Monitor therapy

Sildenafil: Protease Inhibitors may increase the serum concentration of Sildenafil. Management: Erectile dysfunction: sildenafil max = 25 mg/48 hrs with ritonavir, atazanavir, or darunavir; starting dose = 25 mg with other protease inhibitors (adult doses). Contraindicated if sildenafil being used for pulmonary arterial hypertension. Consider therapy modification

Sildenafil: CYP3A4 Inhibitors (Strong) may increase the serum concentration of Sildenafil. Management: Use of sildenafil for pulmonary hypertension should be avoided with strong CYP3A4 inhibitors. When used for erectile dysfunction, starting adult dose should be reduced to 25 mg. Maximum adult dose with ritonavir or cobicistat is 25 mg per 48 hours. Consider therapy modification

Silodosin: CYP3A4 Inhibitors (Strong) may increase the serum concentration of Silodosin. Avoid combination

Siltuximab: May decrease the serum concentration of CYP3A4 Substrates (High risk with Inducers). Monitor therapy

Simeprevir: CYP3A4 Inhibitors (Strong) may increase the serum concentration of Simeprevir. Avoid combination

Simeprevir: Protease Inhibitors may increase the serum concentration of Simeprevir. Simeprevir may increase the serum concentration of Protease Inhibitors. Avoid combination

Simvastatin: Protease Inhibitors may increase the serum concentration of Simvastatin. Avoid combination

Simvastatin: CYP3A4 Inhibitors (Strong) may increase the serum concentration of Simvastatin. Avoid combination

Sirolimus: CYP3A4 Inhibitors (Strong) may increase the serum concentration of Sirolimus. Management: Avoid concurrent use of sirolimus with strong CYP3A4 inhibitors when possible and alternative agents with lesser interaction potential with sirolimus should be considered. Concomitant use of sirolimus and voriconazole or posaconazole is contraindicated. Consider therapy modification

Sirolimus: P-glycoprotein/ABCB1 Inhibitors may increase the serum concentration of Sirolimus. Management: Avoid concurrent use of sirolimus with P-glycoprotein (P-gp) inhibitors when possible and alternative agents with lesser interaction potential with sirolimus should be considered. Monitor for increased sirolimus concentrations/toxicity if combined. Consider therapy modification

Solifenacin: CYP3A4 Inhibitors (Strong) may increase the serum concentration of Solifenacin. Management: Limit adult solifenacin doses to 5 mg daily and limit doses in pediatric patients to the recommended weight-based starting dose (and do not increase the dose) when combined with strong CYP3A4 inhibitors. Consider therapy modification

Sonidegib: CYP3A4 Inhibitors (Strong) may increase the serum concentration of Sonidegib. Avoid combination

SORAfenib: CYP3A4 Inhibitors (Strong) may increase the serum concentration of SORAfenib. Monitor therapy

St John's Wort: May increase the metabolism of Protease Inhibitors. Avoid combination

SUFentanil: CYP3A4 Inhibitors (Strong) may increase the serum concentration of SUFentanil. Management: If a strong CYP3A4 inhibitor is initiated in a patient on sufentanil, consider a sufentanil dose reduction and monitor for increased sufentanil effects and toxicities (eg, respiratory depression). Consider therapy modification

SUNItinib: CYP3A4 Inhibitors (Strong) may increase the serum concentration of SUNItinib. Management: Avoid when possible. If combined, decrease sunitinib dose to a minimum of 37.5 mg daily when treating GIST or RCC. Decrease sunitinib dose to a minimum of 25 mg daily when treating PNET. Monitor patients for both reduced efficacy and increased toxicities. Consider therapy modification

Suvorexant: CYP3A4 Inhibitors (Strong) may increase the serum concentration of Suvorexant. Avoid combination

Tacrolimus (Systemic): Ritonavir may increase the serum concentration of Tacrolimus (Systemic). Management: Tacrolimus dose reductions may be needed with concurrent ritonavir. Monitor tacrolimus concentrations closely to determine dose; doses of tacrolimus 0.5 mg to 1 mg every week may be adequate. Consider therapy modification

Tacrolimus (Topical): Protease Inhibitors may decrease the metabolism of Tacrolimus (Topical). Monitor therapy

Tadalafil: Ritonavir may increase the serum concentration of Tadalafil. Management: In patients treated for pulmonary arterial hypertension avoid initiating ritonavir in patients taking tadalafil; dose adjustments are required. For ED or BPH treatment, decrease tadalafil max dose and frequency. See full monograph for details. Consider therapy modification

Talazoparib: P-glycoprotein/ABCB1 Inhibitors may increase the serum concentration of Talazoparib. Monitor therapy

Talazoparib: BCRP/ABCG2 Inhibitors may increase the serum concentration of Talazoparib. Monitor therapy

Tamsulosin: CYP3A4 Inhibitors (Strong) may increase the serum concentration of Tamsulosin. Avoid combination

Tasimelteon: CYP3A4 Inhibitors (Strong) may increase the serum concentration of Tasimelteon. Monitor therapy

Tazemetostat: CYP3A4 Inhibitors (Strong) may increase the serum concentration of Tazemetostat. Avoid combination

Tegaserod: P-glycoprotein/ABCB1 Inhibitors may increase the serum concentration of Tegaserod. Monitor therapy

Telithromycin: CYP3A4 Inhibitors (Strong) may increase the serum concentration of Telithromycin. Monitor therapy

Temsirolimus: CYP3A4 Inhibitors (Strong) may increase the serum concentration of Temsirolimus. Management: Avoid concomitant use of temsirolimus and strong CYP3A4 inhibitors. If coadministration is unavoidable, decrease temsirolimus dose to 12.5 mg per week. Resume previous temsirolimus dose 1 week after discontinuation of the strong CYP3A4 inhibitor. Consider therapy modification

Tenofovir Disoproxil Fumarate: Lopinavir may enhance the nephrotoxic effect of Tenofovir Disoproxil Fumarate. Lopinavir may increase the serum concentration of Tenofovir Disoproxil Fumarate. Monitor therapy

Terfenadine: CYP3A4 Inhibitors (Strong) may increase the serum concentration of Terfenadine. Management: Drugs listed as exceptions to this monograph are discussed in further detail in separate drug interaction monographs. Avoid combination

Tetrahydrocannabinol: CYP3A4 Inhibitors (Strong) may increase the serum concentration of Tetrahydrocannabinol. Monitor therapy

Tetrahydrocannabinol and Cannabidiol: CYP3A4 Inhibitors (Strong) may increase the serum concentration of Tetrahydrocannabinol and Cannabidiol. Monitor therapy

Tezacaftor and Ivacaftor: CYP3A4 Inhibitors (Strong) may increase the serum concentration of Tezacaftor and Ivacaftor. Management: If combined with strong CYP3A4 inhibitors, tezacaftor/ivacaftor should be administered in the morning, twice a week, approximately 3 to 4 days apart. Tezacaftor/ivacaftor dose depends on age and weight; see full Lexi-Interact monograph for details. Consider therapy modification

Theophylline Derivatives: Ritonavir may decrease the serum concentration of Theophylline Derivatives. Exceptions: Dyphylline. Monitor therapy

Thioridazine: CYP2D6 Inhibitors (Weak) may increase the serum concentration of Thioridazine. Management: Consider avoiding concomitant use of thioridazine and weak CYP2D6 inhibitors. If combined, monitor closely for QTc interval prolongation and arrhythmias. Some weak CYP2D6 inhibitors list use with thioridazine as a contraindication. Consider therapy modification

Thiotepa: CYP3A4 Inhibitors (Strong) may decrease serum concentrations of the active metabolite(s) of Thiotepa. CYP3A4 Inhibitors (Strong) may increase the serum concentration of Thiotepa. Management: Thiotepa prescribing information recommends avoiding concomitant use of thiotepa and strong CYP3A4 inhibitors. If concomitant use is unavoidable, monitor for adverse effects and decreased efficacy. Consider therapy modification

Thyroid Products: Ritonavir may diminish the therapeutic effect of Thyroid Products. Monitor therapy

Ticagrelor: CYP3A4 Inhibitors (Strong) may decrease serum concentrations of the active metabolite(s) of Ticagrelor. CYP3A4 Inhibitors (Strong) may increase the serum concentration of Ticagrelor. Avoid combination

Tipranavir: May decrease the serum concentration of Protease Inhibitors. Avoid combination

Tocilizumab: May decrease the serum concentration of CYP3A4 Substrates (High risk with Inducers). Monitor therapy

Tofacitinib: CYP3A4 Inhibitors (Strong) may increase the serum concentration of Tofacitinib. Management: Tofacitinib dose reductions are recommended when combined with strong CYP3A4 inhibitors. Recommended dose adjustments vary by tofacitinib formulation and therapeutic indication. See full Lexi Interact monograph for details. Consider therapy modification

Tolterodine: CYP3A4 Inhibitors (Strong) may increase the serum concentration of Tolterodine. Management: The maximum recommended adult dose of tolterodine is 2 mg/day when used together with a strong CYP3A4 inhibitor. Consider therapy modification

Tolvaptan: CYP3A4 Inhibitors (Strong) may increase the serum concentration of Tolvaptan. Avoid combination

Topotecan: BCRP/ABCG2 Inhibitors may increase the serum concentration of Topotecan. Avoid combination

Topotecan: P-glycoprotein/ABCB1 Inhibitors may increase the serum concentration of Topotecan. Avoid combination

Toremifene: CYP3A4 Inhibitors (Strong) may increase the serum concentration of Toremifene. Management: Use of toremifene with strong CYP3A4 inhibitors should be avoided if possible. If coadministration is necessary, monitor for increased toremifene toxicities, including QTc interval prolongation. Exceptions are discussed in separate monograph. Consider therapy modification

Trabectedin: CYP3A4 Inhibitors (Strong) may increase the serum concentration of Trabectedin. Avoid combination

TraMADol: Ritonavir may decrease serum concentrations of the active metabolite(s) of TraMADol. Ritonavir may increase the serum concentration of TraMADol. Monitor therapy

TraZODone: CYP3A4 Inhibitors (Strong) may increase the serum concentration of TraZODone. Management: Consider the use of a lower trazodone dose and monitor for increased trazodone effects (eg, sedation, QTc prolongation) if combined with strong CYP3A4 inhibitors. Consider therapy modification

Triamcinolone (Systemic): Ritonavir may enhance the adverse/toxic effect of Triamcinolone (Systemic). Specifically, risks of developing iatrogenic Cushing syndrome and secondary adrenal insufficiency may be increased. Ritonavir may increase the serum concentration of Triamcinolone (Systemic). Monitor therapy

Triazolam: CYP3A4 Inhibitors (Strong) may increase the serum concentration of Triazolam. Avoid combination

Ubrogepant: CYP3A4 Inhibitors (Strong) may increase the serum concentration of Ubrogepant. Avoid combination

Udenafil: CYP3A4 Inhibitors (Strong) may increase the serum concentration of Udenafil. Avoid combination

Ulipristal: CYP3A4 Inhibitors (Strong) may increase the serum concentration of Ulipristal. Management: This is specific for when ulipristal is being used for signs/symptoms of uterine fibroids (Canadian indication). When ulipristal is used as an emergency contraceptive, patients receiving this combo should be monitored for ulipristal toxicity. Avoid combination

Upadacitinib: CYP3A4 Inhibitors (Strong) may increase the serum concentration of Upadacitinib. Monitor therapy

Valbenazine: CYP3A4 Inhibitors (Strong) may increase the serum concentration of Valbenazine. Management: Reduce the valbenazine dose to 40 mg daily when combined with strong CYP3A4 inhibitors. Consider therapy modification

Valproate Products: Protease Inhibitors may decrease the serum concentration of Valproate Products. Monitor therapy

Vardenafil: Ritonavir may increase the serum concentration of Vardenafil. Management: Limit Levitra (vardenafil) dose to a single 2.5 mg dose within a 72-hour period if combined with ritonavir. Avoid concomitant use of Staxyn (vardenafil) and ritonavir. Combined use is contraindicated outside of the US. Consider therapy modification

Velpatasvir: Ritonavir may decrease the serum concentration of Velpatasvir. Ritonavir may increase the serum concentration of Velpatasvir. Management: Coadministration of sofosbuvir/velpatasvir with moderate or strong inducers of CYP2B6 is not recommended. Coadministration of tipranavir/ritonavir is specifically not recommended, but coadministration of atazanavir/ritonavir and darunavir is permitted. Consider therapy modification

Vemurafenib: CYP3A4 Inhibitors (Strong) may increase the serum concentration of Vemurafenib. Management: Avoid concurrent use of vemurafenib with strong CYP3A4 inhibitors when possible. If concomitant use is unavoidable, consider a vemurafenib dose reduction if clinically indicated. Consider therapy modification

Venetoclax: CYP3A4 Inhibitors (Strong) may increase the serum concentration of Venetoclax. Management: Coadministration is contraindicated during venetoclax initiation and ramp-up in CLL/SLL patients. Reduced venetoclax doses are required during ramp-up for patients with AML, and all maintenance therapy. See full Lexi Interact monograph for details. Consider therapy modification

Venetoclax: P-glycoprotein/ABCB1 Inhibitors may increase the serum concentration of Venetoclax. Management: Reduce the venetoclax dose by at least 50% in patients requiring concomitant treatment with P-glycoprotein (P-gp) inhibitors. Resume the previous venetoclax dose 2 to 3 days after discontinuation of a P-gp inhibitor. Consider therapy modification

Vilanterol: May increase the serum concentration of CYP3A4 Inhibitors (Strong). Monitor therapy

Vilazodone: CYP3A4 Inhibitors (Strong) may increase the serum concentration of Vilazodone. Management: Limit the maximum vilazodone dose to 20 mg daily in patients receiving strong CYP3A4 inhibitors. The original vilazodone dose can be resumed following discontinuation of the strong CYP3A4 inhibitor. Consider therapy modification

VinBLAStine: CYP3A4 Inhibitors (Strong) may increase the serum concentration of VinBLAStine. Monitor therapy

VinCRIStine: CYP3A4 Inhibitors (Strong) may increase the serum concentration of VinCRIStine. Management: Seek alternatives to this combination when possible. If combined, monitor closely for vincristine toxicities (eg, neurotoxicity, gastrointestinal toxicity, myelosuppression). Consider therapy modification

VinCRIStine (Liposomal): CYP3A4 Inhibitors (Strong) may increase the serum concentration of VinCRIStine (Liposomal). Avoid combination

VinCRIStine (Liposomal): P-glycoprotein/ABCB1 Inhibitors may increase the serum concentration of VinCRIStine (Liposomal). Avoid combination

Vindesine: CYP3A4 Inhibitors (Strong) may increase the serum concentration of Vindesine. Monitor therapy

Vinflunine: CYP3A4 Inhibitors (Strong) may increase the serum concentration of Vinflunine. Avoid combination

Vinorelbine: CYP3A4 Inhibitors (Strong) may increase the serum concentration of Vinorelbine. Monitor therapy

Vitamin K Antagonists (eg, warfarin): Ritonavir may decrease the serum concentration of Vitamin K Antagonists. Monitor therapy

Vorapaxar: CYP3A4 Inhibitors (Strong) may increase the serum concentration of Vorapaxar. Avoid combination

Voriconazole: Ritonavir may decrease the serum concentration of Voriconazole. Management: Concurrent voriconazole and high-dose ritonavir (adult doses of 400 mg every 12 hrs or greater) is contraindicated. Voriconazole with lower-dose ritonavir should be avoided unless benefits outweigh risk of inadequate voriconazole concentrations. Avoid combination

Voriconazole: Lopinavir may decrease the serum concentration of Voriconazole. Avoid combination

Voxelotor: CYP3A4 Inhibitors (Strong) may increase the serum concentration of Voxelotor. Management: Avoid concomitant use of voxelotor and strong CYP3A4 inhibitors. If concomitant use is unavoidable, reduce the voxelotor dose to 1,000 mg once daily. Consider therapy modification

Voxilaprevir: Lopinavir may increase the serum concentration of Voxilaprevir. Avoid combination

Warfarin: Lopinavir may decrease the serum concentration of Warfarin. Monitor therapy

Zanubrutinib: CYP3A4 Inhibitors (Strong) may increase the serum concentration of Zanubrutinib. Management: Decrease the zanubrutinib dose to 80 mg once daily during coadministration with a strong CYP3A4 inhibitor. Further dose adjustments may be required for zanubrutinib toxicities, refer to prescribing information for details. Consider therapy modification

Zidovudine: Protease Inhibitors may decrease the serum concentration of Zidovudine. Monitor therapy

Zolpidem: Ritonavir may increase the serum concentration of Zolpidem. Monitor therapy

Zopiclone: CYP3A4 Inhibitors (Strong) may increase the serum concentration of Zopiclone. Management: If coadministered with strong CYP3A4 inhibitors, initiate zopiclone at 3.75 mg in adults, with a maximum dose of 5 mg. Monitor for zopiclone toxicity (eg, drowsiness, confusion, lethargy, ataxia, respiratory depression). Consider therapy modification

Adverse Reactions

Data presented for short- and long-term combination antiretroviral therapy in both protease inhibitor experienced and naïve patients.

>10%:

Dermatologic: Skin rash (children 12%; adults ≤5%)

Endocrine & metabolic: Hypercholesterolemia (3% to 39%), increased serum triglycerides (3% to 36%), increased gamma-glutamyl transferase (10% to 29%)

Gastrointestinal: Diarrhea (7% to 28%; greater with once-daily dosing), dysgeusia (children 22%; adults <2%), vomiting (children 21%; adults 2% to 7%), nausea (5% to 16%), abdominal pain (1% to 11%)

Hepatic: Increased serum ALT (grade 3/4: 1% to 11%)

Respiratory: Upper respiratory tract infection (14%)

>2% to 10%:

Cardiovascular: Vasodilation (≤3%)

Central nervous system: Fatigue (8%, including weakness), headache (2% to 6%), anxiety (4%), insomnia (≤4%)

Dermatologic: Skin infection (3%, including cellulitis, folliculitis, furuncle)

Endocrine & metabolic: Hypertriglyceridemia (6%), hyperglycemia (≤5%), hyperuricemia (≤5%), alteration in sodium (children 3%), weight loss (≤3%)

Gastrointestinal: Increased serum amylase (3% to 8%), dyspepsia (≤6%), increased serum lipase (3% to 5%), flatulence (1% to 4%), gastroenteritis (3%)

Hematologic & oncologic: Thrombocytopenia (grade 3/4: 4% children), neutropenia (grade 3/4: 1% to 5%)

Hepatic: Increased serum AST (grade 3/4: 2% to 10%), hepatitis (4%, including increased AST, ALT, and gamma-glutamyl transferase), increased serum bilirubin (children 3%; adults 1%)

Hypersensitivity: Hypersensitivity (3%, including urticaria and angioedema)

Neuromuscular & skeletal: Weakness (≤9%), musculoskeletal pain (6%)

Respiratory: Lower respiratory tract infection (8%)

≤2%: Abdominal distension, abnormal dreams, abnormality in thinking, acne vulgaris, ageusia, agitation, alopecia, amenorrhea, amnesia, anemia, anorexia, apathy, arthralgia, asthma, ataxia, atherosclerotic disease, atrial fibrillation, atrioventricular block (second and third degree), atrophic striae, back pain, bacterial infection, benign neoplasm, bradycardia, brain disease, breast hypertrophy, bronchitis, cerebral infarction, cerebrovascular accident, change in appetite, chest pain, chills, cholangitis, cholecystitis, confusion, constipation, cough, Cushing's syndrome, cyst, decreased creatinine clearance, decreased glucose tolerance, decreased libido, deep vein thrombosis, dehydration, depression, dermal ulcer, diabetes mellitus, dizziness, drowsiness, duodenitis, dyskinesia, dysphagia, dyspnea, eczema, edema, ejaculatory disorder, emotional lability, enteritis, enterocolitis, erectile dysfunction, eructation, erythema multiforme, esophagitis, exfoliative dermatitis, extrapyramidal reaction, facial edema, facial paralysis, fecal incontinence, fever, first degree atrioventricular block, flu-like symptoms, gastritis, gastroesophageal reflux disease, gastrointestinal hemorrhage, gastrointestinal ulcer, gynecomastia, hematuria, hemorrhagic colitis, hemorrhoids, hepatic insufficiency, hepatomegaly, hyperacusis, hyperhidrosis, hypermenorrhea, hypersensitivity reaction, hypertension, hypertonia, hypogonadism (males), hypophosphatemia, hypothyroidism, immune reconstitution syndrome, impotence, jaundice, lactic acidosis, leukopenia, lipoma, liver steatosis, liver tenderness, lymphadenopathy, maculopapular rash, malaise, migraine, myalgia, myocardial infarction, neoplasm, nephritis, nervousness, neuropathy, night sweats, obesity, oral mucosa ulcer, orthostatic hypotension, osteonecrosis, otitis media, palpitations, pancreatitis, paresthesia, periodontitis, peripheral edema, peripheral neuropathy, pharyngitis, prolonged QT interval on ECG, propylene glycol toxicity (preterm neonates [includes cardiomyopathy, lactic acidosis, acute renal failure, respiratory complications]), pruritus, pulmonary edema, rectal hemorrhage, redistribution of body fat (including facial wasting), renal failure, rhabdomyolysis, rhinitis, seborrhea, seizure, sialadenitis, sinusitis, skin discoloration, splenomegaly, Stevens-Johnson syndrome, stomatitis, thrombophlebitis, tinnitus, torsades de pointes, tremor, tricuspid regurgitation, vasculitis, vertigo, viral infection, visual disturbance, vitamin deficiency, weight gain, xeroderma, xerostomia

Warnings/Precautions

Concerns related to adverse effects:

• Altered cardiac conduction: May alter cardiac conduction and prolong the QTc and/or PR interval; second- and third-degree AV block and torsade de pointes have been observed. Use with caution in patients with underlying structural heart disease, preexisting conduction system abnormalities, ischemic heart disease or cardiomyopathies. Avoid use in combination with QTc- or PR-interval prolonging drugs or in patients with hypokalemia or congenital long QT syndrome.

• Cardiovascular concerns: Possible higher risk of myocardial infarction associated with the cumulative use of lopinavir/ritonavir; consider avoiding lopinavir/ritonavir-based regimens in patients with high cardiac risk (Bavinger 2013; HHS [adult] 2019).

• Fat redistribution: May cause redistribution/accumulation of fat (eg, central obesity, buffalo hump, peripheral wasting, facial wasting, breast enlargement, cushingoid appearance).

• Hepatotoxicity: May cause hepatitis and/or exacerbate pre-existing hepatic dysfunction; use with caution in patients with underlying hepatic disease, such as hepatitis B or C, cirrhosis, or unspecified hepatic impairment. Consider more frequent liver function test monitoring during therapy initiation in patients with preexisting hepatic dysfunction.

• Immune reconstitution syndrome: Patients may develop immune reconstitution syndrome resulting in the occurrence of an inflammatory response to an indolent or residual opportunistic infection during initial HIV treatment or activation of autoimmune disorders (eg, Graves’ disease, polymyositis, Guillain-Barré syndrome) later in therapy; further evaluation and treatment may be required.

• Increased cholesterol: Increases in total cholesterol and triglycerides have been reported; screening should be done prior to therapy and periodically throughout treatment.

Disease-related concerns:

• Diabetes: Changes in glucose tolerance, hyperglycemia, exacerbation of diabetes, DKA, and new-onset diabetes mellitus have been reported in patients receiving protease inhibitors. Consider monitoring for these conditions. In some patients who discontinued protease inhibitors, hyperglycemia persisted.

• Hemophilia A or B: Use with caution in patients with hemophilia A or B; increased bleeding during protease inhibitor therapy has been reported.

• Hepatic impairment: Use with caution; lopinavir concentrations may be increased.

• Pancreatitis: Use with caution in patients with increased triglycerides; pancreatitis has been observed. Patients with history of pancreatitis or advanced HIV-1 disease may be at increased risk. Monitor for clinical symptoms (nausea, vomiting, abdominal pain) and serum lipase and amylase.

Special populations:

• Pediatric: Safety, efficacy, and pharmacokinetic profiles of lopinavir and ritonavir have not been established for neonates <14 days of age. Neonates <14 days of age, particularly preterm neonates, are at risk for developing propylene glycol toxicity with use of the lopinavir/ritonavir oral solution. Oral solution contains ethanol and propylene glycol; ethanol competitively inhibits propylene glycol metabolism. Postmarketing reports in preterm neonates following use of the oral solution include cardiotoxicity (complete AV block, bradycardia, cardiomyopathy), lactic acidosis, CNS depression, respiratory complications, acute renal failure, and death. The oral solution should not be used in the immediate postnatal period, including full-term neonates age <14 days or preterm neonates until 14 days after their due date, unless the infant is closely monitored and benefits clearly outweigh risk. Once-daily dosing (oral solution or tablets) is not an approved regimen for children <18 years of age.

Dosage form specific issues:

• Oral solution: The oral solution is highly concentrated and contains large amounts of ethanol (42.4%) and propylene glycol (15.3%). Monitor patients with renal impairment or with decreased ability to metabolize propylene glycol (eg, patients of Asian origin) for propylene glycol toxicity (eg, seizures tachycardia, lactic acidosis, hyperosmolarity, stupor, hemolysis). Health care providers should pay special attention to accurate calculation, measurement, and administration of dose. Overdose (or cumulative ethanol or propylene glycol content in medications) in a child may lead to lethal ethanol or propylene glycol toxicity.

Other warnings/precautions:

• Appropriate use: Once-daily dosing is not recommended in patients with ≥3 of the following lopinavir-resistance-associated amino acid substitutions in protease (L10F/I/R/V, K20M/N/R, L24I, L33F, M36I, I47V, G48V, I54L/T/V, V82A/C/F/S/T, and I84V); those receiving efavirenz, fosamprenavir, nevirapine, or nelfinavir, carbamazepine, phenobarbital, phenytoin, or in children <18 years of age.

Monitoring Parameters

Prior to therapy, consider genotypic or phenotypic testing for lopinavir resistance-associated substitutions.

Triglycerides and cholesterol (prior to initiation then periodically thereafter), LFTs, electrolytes, basic HIV monitoring, viral load and CD4 count, glucose

Reproductive Considerations

The Health and Human Services (HHS) perinatal HIV guidelines consider lopinavir combined with ritonavir an alternative protease inhibitor for females living with HIV who are not yet pregnant but are trying to conceive.

For males and females living with HIV and planning a pregnancy, maximum viral suppression below the limits of detection with antiretroviral therapy (ART), modification of therapy (if needed), optimization of the woman's health, and a discussion of the potential risks and benefits of ART therapy during pregnancy is recommended prior to conception (HHS [perinatal] 2019).

Pregnancy Considerations

Lopinavir has a low level of transfer across the human placenta; fetal exposure is increased with ritonavir.

Based on information collected by the Antiretroviral Pregnancy Registry, an increased risk of teratogenic effects has not been observed in humans. Maternal antiretroviral therapy (ART) may be associated with adverse pregnancy outcomes including preterm delivery, stillbirth, low birth weight, and small for gestational age infants. Actual risks may be influenced by maternal factors, such as disease severity, gestational age at initiation of therapy, and specific ART regimen, therefore close fetal monitoring is recommended. However, regimens containing lopinavir/ritonavir may be more closely associated with preterm delivery compared to others. Because there is clear benefit to appropriate treatment, maternal ART should not be withheld due to concerns for adverse neonatal outcomes. Long-term follow-up is recommended for all infants exposed to antiretroviral medications; children without HIV but who were exposed to ART in utero and develop significant organ system abnormalities of unknown etiology (particularly of the CNS or heart) should be evaluated for potential mitochondrial dysfunction. Hyperglycemia, new onset of diabetes mellitus, or diabetic ketoacidosis have been reported with protease inhibitors; it is not clear if pregnancy increases this risk. Consider performing the standard glucose screening test earlier in pregnancy in women who initiated protease inhibitor therapy prior to conception.

The Health and Human Services (HHS) perinatal HIV guidelines consider lopinavir combined with ritonavir an alternative protease inhibitor for pregnant females living with HIV who are antiretroviral-naive (initial therapy), who have had ART therapy in the past but are restarting, or who require a new ART regimen (due to poor tolerance or poor virologic response of current regimen). Females who become pregnant while taking lopinavir combined with ritonavir may continue if viral suppression is effective and the regimen is well tolerated. Pharmacokinetic studies suggest that standard dosing during pregnancy may provide decreased plasma concentrations; dose adjustments are required in women during the second and third trimesters of pregnancy. Although there is an abundance of data related to the use of lopinavir/ritonavir during pregnancy, the HHS perinatal HIV guidelines consider lopinavir/ritonavir to be an alternative protease inhibitor for initial therapy in antiretroviral-naive pregnant women due to the need for twice daily dosing, the increased incidence of diarrhea and nausea, and an association with preterm delivery. Lopinavir/ritonavir is not recommended for use in pregnant women with lopinavir-associated resistance substitutions. In addition, once-daily dosing is not recommended during pregnancy and use of the oral solution should be avoided (due to alcohol and propylene glycol content).

In general, ART is recommended for all pregnant females living with HIV to keep the viral load below the limit of detection and reduce the risk of perinatal transmission. Therapy should be individualized following a discussion of the potential risks and benefits of treatment during pregnancy. Monitoring of pregnant females is more frequent than in nonpregnant adults. ART should be continued postpartum for all females living with HIV and can be modified after delivery.

Lopinavir/ritonavir is under investigation for use in the treatment of COVID-19 (see http://www.ClinicalTrials.gov) and should only be given as part of a clinical trial for this indication (HHS 2020). The American College of Obstetricians and Gynecologists and the Society for Maternal-Fetal Medicine have developed an algorithm to aid practitioners in assessing and managing pregnant women with suspected or confirmed COVID-19 (https://www.acog.org/topics/covid-19; https://www.smfm.org/covid19). Interim guidance is also available from the CDC for pregnant women who are diagnosed with COVID-19 (https://www.cdc.gov/coronavirus/2019-ncov/hcp/inpatient-obstetric-healthcare-guidance.html).

Health care providers are encouraged to enroll pregnant females exposed to antiretroviral medications as early in pregnancy as possible in the Antiretroviral Pregnancy Registry (1-800-258-4263 or http://www.APRegistry.com). Health care providers caring for pregnant females living with HIV and their infants may contact the National Perinatal HIV Hotline (888-448-8765) for clinical consultation (HHS [perinatal] 2019).

Data collection to monitor maternal and infant outcomes following exposure to COVID-19 during pregnancy is ongoing. Health care providers are encouraged to enroll females exposed to COVID-19 during pregnancy in the Organization of Teratology Information Specialists pregnancy registry (877-311-8972; https://mothertobaby.org/join-study/) or the PRIORITY (Pregnancy CoRonavIrus Outcomes RegIsTrY) (415-754-3729, https://priority.ucsf.edu/).

Patient Education

What is this drug used for?

• It is used to treat HIV infection.

All drugs may cause side effects. However, many people have no side effects or only have minor side effects. Call your doctor or get medical help if any of these side effects or any other side effects bother you or do not go away:

• Back pain

• Nausea

• Vomiting

• Joint pain

• Muscle pain

• Headache

• Abdominal pain

• Diarrhea

• Loss of strength and energy

• Common cold symptoms

WARNING/CAUTION: Even though it may be rare, some people may have very bad and sometimes deadly side effects when taking a drug. Tell your doctor or get medical help right away if you have any of the following signs or symptoms that may be related to a very bad side effect:

• Infection

• Liver problems like dark urine, feeling tired, lack of appetite, nausea, abdominal pain, light-colored stools, vomiting, or yellow skin or eyes

• High blood sugar (confusion, feeling sleepy, more thirst, hunger, passing urine more often, flushing, fast breathing, or breath that smells like fruit

• Pancreatitis like severe abdominal pain, severe back pain, severe nausea, or vomiting

• Chest pain

• Fast heartbeat

• Abnormal heartbeat

• Dizziness

• Passing out

• Bruising

• Bleeding

• Change in fat

• Stevens-Johnson syndrome/toxic epidermal necrolysis like red, swollen, blistered, or peeling skin (with or without fever); red or irritated eyes; or sores in mouth, throat, nose, or eyes

• Signs of an allergic reaction, like rash; hives; itching; red, swollen, blistered, or peeling skin with or without fever; wheezing; tightness in the chest or throat; trouble breathing, swallowing, or talking; unusual hoarseness; or swelling of the mouth, face, lips, tongue, or throat.

Note: This is not a comprehensive list of all side effects. Talk to your doctor if you have questions.

Consumer Information Use and Disclaimer: This information should not be used to decide whether or not to take this medicine or any other medicine. Only the healthcare provider has the knowledge and training to decide which medicines are right for a specific patient. This information does not endorse any medicine as safe, effective, or approved for treating any patient or health condition. This is only a limited summary of general information about the medicine's uses from the patient education leaflet and is not intended to be comprehensive. This limited summary does NOT include all information available about the possible uses, directions, warnings, precautions, interactions, adverse effects, or risks that may apply to this medicine. This information is not intended to provide medical advice, diagnosis or treatment and does not replace information you receive from the healthcare provider. For a more detailed summary of information about the risks and benefits of using this medicine, please speak with your healthcare provider and review the entire patient education leaflet.

Further information

Always consult your healthcare provider to ensure the information displayed on this page applies to your personal circumstances.