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Ombitasvir, Paritaprevir, and Ritonavir

Pronunciation

(om BIT as vir, par i TA pre vir, & ri TOE na vir)

Index Terms

  • Paritaprevir, Ombitasvir, and Ritonavir
  • Ritonavir, Ombitasvir, and Paritaprevir

Dosage Forms

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

Tablet, Oral:

Technivie: Ombitasvir 12.5 mg, paritaprevir 75 mg, and ritonavir 50 mg

Brand Names: U.S.

  • Technivie

Pharmacologic Category

  • Antihepaciviral, NS3/4A Protease Inhibitor (Anti-HCV)
  • Antihepaciviral, NS5A Inhibitor
  • Cytochrome P-450 Inhibitor
  • NS3/4A Inhibitor
  • NS5A Inhibitor

Pharmacology

Combines 2 direct-acting hepatitis C virus antiviral agents with distinct mechanisms of action. Ombitasvir inhibits HCV NS5A, and interferes with viral RNA replication and virion assembly. Paritaprevir inhibits HCV NS3/4A protease and interferes with HCV coded polyprotein cleavage necessary for viral replication.

Ritonavir is not active against HCV. Ritonavir is a potent CYP3A inhibitor that increases peak and trough plasma drug concentrations of paritaprevir and overall drug exposure (ie, AUC).

Absorption

Well absorbed when administered with food

Distribution

Ombitasvir: Vd: 173 L

Paritaprevir: Vd: 103 L

Ritonavir: Vd: 21.5 L

Metabolism

Ombitasvir: Metabolized by amide hydrolysis and oxidative metabolism

Paritaprevir: Metabolized by CYP3A4 and to a lesser extent CYP3A5

Ritonavir: Metabolized by CYP3A and to a lesser extent CYP2D6

Excretion

Ombitasvir: Feces (90.2%, mainly as unchanged drug); urine (1.91%, mainly as unchanged drug)

Paritaprevir: Feces (88%, mainly as metabolites); urine (8.8%, mainly as metabolites)

Ritonavir: Feces (86.4%); urine (11.3%)

Time to Peak

Ombitasvir, paritaprevir, ritonavir: 4 to 5 hours

Half-Life Elimination

Ombitasvir: 21 to 25 hours; Paritaprevir: 5.5 hours; Ritonavir: 4 hours

Protein Binding

Ombitasvir: 99.9%; Paritaprevir: ~98%; Ritonavir: >99%

Use: Labeled Indications

Chronic hepatitis C: Treatment of chronic hepatitis C virus (HCV) genotype 4 infection without cirrhosis or with compensated cirrhosis, in combination with ribavirin.

Contraindications

Hypersensitivity to ritonavir (eg, toxic epidermal necrolysis, Stevens-Johnson syndrome) or any component of the formulation; moderate to severe hepatic impairment (Child-Pugh class B or C); concurrent use of drugs that are highly dependent on CYP3A for clearance and for which elevated plasma concentrations are associated with serious and/or life-threatening events; concurrent use of moderate or strong inducers of CYP3A. Concurrent use of drugs that are contraindicated include, but are not necessarily limited to: Alfuzosin, atorvastatin, colchicine (in patients with renal and/or hepatic impairment), carbamazepine, cisapride, dronedarone, ergot derivatives (ergonovine, ergotamine, dihydroergotamine, methylergonovine), ethinyl estradiol-containing products, efavirenz, everolimus, lovastatin, lurasidone, midazolam (oral), phenobarbital, phenytoin, pimozide, ranolazine, rifampin, sildenafil (when used for the treatment of pulmonary arterial hypertension [eg, Revatio]), simvastatin, sirolimus, St John's wort, tacrolimus, triazolam. Note: Contraindications to ribavirin also apply; see ribavirin prescribing information.

Canadian labeling: Additional contraindications (not in US labeling): Concurrent use with avasimibe (not available in Canada), nafcillin (not available in Canada), fusidic acid (oral) (not available in Canada), astemizole, terfenadine, etravirine, nevirapine, bosentan, salmeterol, or modafinil.

Dosing: Adult

Chronic hepatitis C, genotype 4 (without cirrhosis or with compensated cirrhosis [Child-Pugh class A]): Oral: Two tablets once daily (every morning) for 12 weeks, in combination with ribavirin. Note: Administration without ribavirin for 12 weeks may be considered for treatment-naive patients without cirrhosis unable to take or tolerate ribavirin.

Dosing: Geriatric

Refer to adult dosing.

Dosing: Renal Impairment

CrCl ≥15 mL/minute: No dosage adjustment necessary.

End-stage renal disease (ESRD) on dialysis: There are no dosage adjustments provided in the manufacturer's labeling (has not been studied).

Dosing: Hepatic Impairment

Hepatic impairment prior to treatment initiation:

Mild impairment (Child-Pugh class A): No dosage adjustment necessary.

Moderate or severe impairment (Child-Pugh class B or C): Use is contraindicated.

Hepatotoxicity during treatment:

ALT >10 times ULN (persistent): Consider therapy discontinuation.

ALT increased along with signs or symptoms of hepatic inflammation, increasing direct bilirubin, alkaline phosphatase, or INR: Discontinue therapy.

Evidence of hepatic decompensation: Discontinue therapy

Administration

Oral: Administer in the morning with a meal.

Storage

Store at or below 30°C (86°F). Dispense in original carton.

Drug Interactions

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

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. Avoid combination

Afatinib: P-glycoprotein/ABCB1 Inhibitors may increase the serum concentration of Afatinib. Management: Per US labeling: reduce afatinib by 10mg if not tolerated. Per Canadian labeling: avoid combination if possible; if used, administer the P-gp inhibitor simultaneously with or after the dose of afatinib. Consider therapy modification

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

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 adult dose to 6.25 mg and maximum adult dose to 12.5 mg/24-hrs 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

ALPRAZolam: Ombitasvir, Paritaprevir, and Ritonavir may increase the serum concentration of ALPRAZolam. Monitor therapy

Amiodarone: Ombitasvir, Paritaprevir, and Ritonavir may increase the serum concentration of Amiodarone. Monitor therapy

AmLODIPine: Antihepaciviral Combination Products may increase the serum concentration of AmLODIPine. Management: Reduce amlodipine dose by at least 50% and monitor for increased amlodipine effects (eg, hypotension) if an antihepaciviral combination product is initiated. Consider therapy modification

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: 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: Please refer to the full interaction monograph for details concerning the recommended dose adjustments. Consider therapy modification

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

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

Asunaprevir: OATP1B1/SLCO1B1 Inhibitors may increase the serum concentration of Asunaprevir. Avoid combination

Atazanavir: May increase the serum concentration of Ombitasvir, Paritaprevir, and Ritonavir. Specifically, the paritaprevir component may increase significantly. Avoid combination

AtorvaSTATin: Antihepaciviral Combination Products may increase the serum concentration of AtorvaSTATin. Avoid combination

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

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

Bedaquiline: CYP3A4 Inhibitors (Strong) may increase the serum concentration of Bedaquiline. Management: Limit the duration of concomitant administration of bedaquiline with CYP3A4 inhibitors to no more than 14 days, unless the benefit of continued administration is judged to outweigh the possible risks. Monitor for toxic effects of bedaquiline. Consider therapy modification

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

Bepridil: Antihepaciviral Combination Products may increase the serum concentration of Bepridil. Monitor therapy

Betrixaban: P-glycoprotein/ABCB1 Inhibitors may increase the serum concentration of Betrixaban. Management: Decrease the betrixaban dose to an initial single dose of 80 mg followed by 40 mg once daily if combined with a P-glycoprotein inhibitor. Consider therapy modification

Bilastine: P-glycoprotein/ABCB1 Inhibitors may increase the serum concentration of Bilastine. Management: Consider alternatives when possible; bilastine should be avoided in patients with moderate to severe renal insufficiency who are receiving p-glycoprotein inhibitors. Consider therapy modification

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

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

Brentuximab Vedotin: P-glycoprotein/ABCB1 Inhibitors 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 to 50% of usual with a strong CYP3A4 inhibitor; reduce to 25% of usual if used with both a moderate CYP3A4 inhibitor and a CYP2D6 inhibitor, or if a strong CYP3A4 inhibitor is 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

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

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

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). Avoid combination

Budesonide (Topical): CYP3A4 Inhibitors (Strong) may increase the serum concentration of Budesonide (Topical). Management: Per US prescribing information, avoid this combination. Canadian product labeling does not recommend strict avoidance. If combined, monitor for excessive glucocorticoid effects as budesonide exposure may be increased. Consider therapy modification

Buprenorphine: Ombitasvir, Paritaprevir, and Ritonavir may increase the serum concentration of Buprenorphine. Monitor therapy

BuPROPion: Antihepaciviral Combination Products may decrease the serum concentration of BuPROPion. Monitor therapy

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, cabozantinib dose adjustments are recommended and vary based on the cabozantinib product used and the indication for use. See monograph for details. Consider therapy modification

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

Candesartan: Antihepaciviral Combination Products may increase the serum concentration of Candesartan. Management: Per antihepaciviral combination product US prescribing information, consider decreasing the candesartan dose and monitoring for evidence of hypotension and worsening renal function if these agents are used in combination. 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

Cariprazine: CYP3A4 Inhibitors (Strong) may increase the serum concentration of Cariprazine. Management: Cariprazine dose reductions of 50% are required; specific recommended management varies slightly for those stable on cariprazine versus those just starting cariprazine. See prescribing information or full interaction monograph for details. Consider therapy modification

Carisoprodol: Ombitasvir, Paritaprevir, and Ritonavir may decrease the serum concentration of Carisoprodol. 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. Avoid combination

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

Cisapride: Antihepaciviral Combination Products may increase the serum concentration of Cisapride. Avoid combination

Clarithromycin: Antihepaciviral Combination Products may increase the serum concentration of Clarithromycin. Management: Avoid clarithromycin doses greater than 1000 mg/day when used with an antihepaciviral combination product. Further dose reductions may be needed in patients with impaired renal function. Consider an alternative antimicrobial for any non-MAC infection. Consider therapy modification

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

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

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

Colchicine: Antihepaciviral Combination Products may increase the serum concentration of Colchicine. Avoid combination

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

Conivaptan: May increase the serum concentration of CYP3A4 Substrates (High risk with Inhibitors). 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 (Orally Inhaled): CYP3A4 Inhibitors (Strong) may increase the serum concentration of Corticosteroids (Orally Inhaled). Management: Orally inhaled fluticasone propionate with a strong CYP3A4 inhibitor is not recommended. Exceptions: Beclomethasone (Oral Inhalation); Triamcinolone (Systemic). Monitor therapy

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. Avoid combination

Cyclobenzaprine: Ombitasvir, Paritaprevir, and Ritonavir may decrease the serum concentration of Cyclobenzaprine. Monitor therapy

CycloSPORINE (Systemic): Ombitasvir, Paritaprevir, and Ritonavir may increase the serum concentration of CycloSPORINE (Systemic). Management: Reduce cyclosporine dose by 80% when initiating therapy with ombitasvir/paritaprevir/ritonavir and monitor cyclosporine blood levels closely. Consider therapy modification

CYP3A4 Inducers (Moderate): May decrease the serum concentration of Antihepaciviral Combination Products. Avoid combination

CYP3A4 Inducers (Strong): May decrease the serum concentration of Antihepaciviral Combination Products. Avoid combination

CYP3A4 Inhibitors (Moderate): May decrease the metabolism of CYP3A4 Substrates (High risk with Inhibitors). Monitor therapy

CYP3A4 Inhibitors (Strong): May decrease the metabolism of CYP3A4 Substrates (High risk with Inhibitors). Consider therapy modification

CYP3A4 Substrates (High risk with Inhibitors): CYP3A4 Inhibitors (Strong) may decrease the metabolism of CYP3A4 Substrates (High risk with Inhibitors). Exceptions: Alitretinoin (Systemic); AmLODIPine; Buprenorphine; Gefitinib; HYDROcodone; Praziquantel; Telithromycin; Vinorelbine. Consider therapy modification

Dabigatran Etexilate: P-glycoprotein/ABCB1 Inhibitors may increase serum concentrations of the active metabolite(s) of Dabigatran Etexilate. Management: Dabigatran dose reductions may be needed. Specific recommendations vary considerably according to US vs Canadian labeling, specific P-gp inhibitor, renal function, and indication for dabigatran treatment. Refer to full monograph or dabigatran labeling. 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

Darunavir: Ombitasvir, Paritaprevir, and Ritonavir may decrease the serum concentration of Darunavir. Management: These agents can be combined in treatment naive patients or those with no darunavir resistance if the darunavir dose is 800 mg daily, darunavir is administered at the same time as the combination product, and darunavir is given without ritonavir. Consider therapy modification

Dasatinib: CYP3A4 Inhibitors (Strong) may increase the serum concentration of Dasatinib. Management: Use of this combination should be avoided; consider reducing dasatinib dose if a strong CYP3A4 inhibitor must be used. If using dasatinib 100 mg/day, consider reduction to 20 mg/day; if using dasatinib 140 mg/day, consider reduction to 40 mg/day. Consider therapy modification

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

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 electrocardiogram (ECG) monitoring frequency if delamanid is combined with strong CYP3A4 inhibitors because the risk for QTc interval prolongation may be increased. Continue frequent ECG assessments throughout the full delamanid treatment period. Consider therapy modification

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

DiazePAM: Ombitasvir, Paritaprevir, and Ritonavir may decrease the serum concentration of DiazePAM. Monitor therapy

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

Digoxin: Ombitasvir, Paritaprevir, and Ritonavir may increase the serum concentration of Digoxin. Management: When initiating the ombitasvir/paritaprevir/ritonavir combination product in patients taking digoxin, decrease the digoxin dose by 30% to 50% and monitor serum digoxin levels to determine further dose adjustments. Consider therapy modification

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. Avoid combination

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

DOXOrubicin (Conventional): CYP3A4 Inhibitors (Strong) may increase the serum concentration of DOXOrubicin (Conventional). Management: Seek alternatives to strong CYP3A4 inhibitors in patients treated with doxorubicin whenever possible. One U.S. manufacturer (Pfizer Inc.) recommends that these combinations be avoided. Consider therapy modification

DOXOrubicin (Conventional): P-glycoprotein/ABCB1 Inhibitors may increase the serum concentration of DOXOrubicin (Conventional). Management: Seek alternatives to P-glycoprotein inhibitors in patients treated with doxorubicin whenever possible. One U.S. manufacturer (Pfizer Inc.) recommends that these combinations be avoided. Consider therapy modification

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

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

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

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

Edoxaban: P-glycoprotein/ABCB1 Inhibitors may increase the serum concentration of Edoxaban. Management: See full monograph for details. Reduced doses are recommended for patients receiving edoxaban for venous thromboembolism in combination with certain inhibitors. Similar dose adjustment is not recommended for edoxaban use in atrial fibrillation. Consider therapy modification

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

Eliglustat: CYP3A4 Inhibitors (Strong) may increase the serum concentration of Eliglustat. Management: Use should be avoided under some circumstances. See full drug interaction monograph for details. Consider therapy modification

Eluxadoline: Antihepaciviral Combination Products may increase the serum concentration of Eluxadoline. Management: Decrease the eluxadoline dose to 75 mg twice daily if combined with antihepaciviral combination products. Monitor patients for increased eluxadoline effects/toxicities. Consider therapy modification

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

Ergot Derivatives: Antihepaciviral Combination Products may increase the serum concentration of Ergot Derivatives. Exceptions: Cabergoline; 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

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

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

Ethinyl Estradiol: May enhance the hepatotoxic effect of Antihepaciviral Combination Products. Management: Use of ethinyl estradiol must be discontinued prior to use of this combination; ethinyl estradiol can be restarted 2 weeks after cessation of the antihepaciviral combination product. Avoid combination

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

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

Everolimus: Antihepaciviral Combination Products may increase the serum concentration of Everolimus. Avoid combination

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

FentaNYL: CYP3A4 Inhibitors (Strong) may increase the serum concentration of FentaNYL. Management: Monitor patients closely for several days following initiation of this combination, and adjust fentanyl dose as necessary. Consider therapy modification

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

Flecainide: Antihepaciviral Combination Products may increase the serum concentration of Flecainide. Management: Canadian labeling recommends avoiding this combination. Monitor therapy

Flibanserin: CYP3A4 Inhibitors (Strong) may increase the serum concentration 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). Management: Use of orally inhaled fluticasone propionate with strong CYP3A4 inhibitors is not recommended. Use of orally inhaled fluticasone furoate with strong CYP3A4 inhibitors should be done with caution. Monitor patients using such a combination more closely. Consider therapy modification

Fusidic Acid (Systemic): May increase the serum concentration of CYP3A4 Substrates (High risk with Inhibitors). Avoid combination

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

Grazoprevir: OATP1B1/SLCO1B1 Inhibitors may increase the serum concentration of Grazoprevir. Avoid combination

GuanFACINE: CYP3A4 Inhibitors (Strong) may increase the serum concentration of GuanFACINE. Management: Reduce the guanfacine dose by 50% when initiating this combination. Consider therapy modification

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

HYDROcodone: Ombitasvir, Paritaprevir, and Ritonavir may increase the serum concentration of HYDROcodone. Management: Reduce the hydrocodone dose by 50% during concurrent use of ombitasvir, paritaprevir, and ritonavir; monitor closely for both analgesic effectiveness and for signs of toxicity or withdrawal. Consider therapy modification

HydrOXYzine: CYP3A4 Inhibitors (Strong) may increase the serum concentration of HydrOXYzine. Management: This combination is specifically contraindicated in some non-U.S. labeling. Consider therapy modification

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: May increase the serum concentration of CYP3A4 Substrates (High risk with Inhibitors). Avoid combination

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

Irinotecan Products: UGT1A1 Inhibitors may increase serum concentrations of the active metabolite(s) of Irinotecan Products. Specifically, concentrations of SN-38 may be increased. UGT1A1 Inhibitors 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

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 monograph content for specific age- and weight-based recommendations. Consider therapy modification

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

Ketoconazole (Systemic): Antihepaciviral Combination Products may increase the serum concentration of Ketoconazole (Systemic). Ketoconazole (Systemic) may increase the serum concentration of Antihepaciviral Combination Products. Specifically, ketoconazole may increase serum concentrations of paritaprevir. Management: Limit the dose of ketoconazole to 200 mg per day in patients taking antihepaciviral combination products. Additionally, monitor for increased ketoconazole effects/toxicities and for increased paritaprevir effects/toxicities. Consider therapy modification

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

Lapatinib: CYP3A4 Inhibitors (Strong) may increase the serum concentration of Lapatinib. Management: If an overlap in therapy cannot be avoided, consider reducing lapatinib adult dose to 500 mg/day during, and within 1 week of completing, treatment with the strong CYP3A4 inhibitor. Avoid combination

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

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

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

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

Losartan: Antihepaciviral Combination Products may increase the serum concentration of Losartan. Management: Per antihepaciviral combination product US prescribing information, consider decreasing the losartan dose and monitoring for evidence of hypotension and worsening renal function if these agents are used in combination. Consider therapy modification

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

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 the adult dose of maraviroc to 150 mg twice daily when used with a strong CYP3A4 inhibitor. Do not use maraviroc with strong CYP3A4 inhibitors in patients with Clcr less than 30 mL/min. Consider therapy modification

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

MetFORMIN: Ombitasvir, Paritaprevir, and Ritonavir may enhance the adverse/toxic effect of MetFORMIN. Specifically, the risk for lactic acidosis may be increased. Monitor therapy

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

Mexiletine: Antihepaciviral Combination Products may increase the serum concentration of Mexiletine. Monitor therapy

Midazolam: Antihepaciviral Combination Products may increase the serum concentration of Midazolam. Management: Oral midazolam contraindicated with antihepaciviral combination products. When used with intravenous midazolam, monitor for increased midazolam effects (eg, sedation, respiratory depression) and consider using a reduced midazolam dose. 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. Consider therapy modification

MiFEPRIStone: CYP3A4 Inhibitors (Strong) may increase the serum concentration of MiFEPRIStone. Management: Limit mifepristone adult dose, when used for treatment of hyperglycemia in Cushing's syndrome, to a maximum of 600 mg/day when combined with a strong CYP3A4 inhibitor. Monitor for increased mifepristone toxicity regardless of dose or indication. Consider therapy modification

MiFEPRIStone: May increase the serum concentration of CYP3A4 Substrates (High risk with Inhibitors). Management: Minimize doses of CYP3A4 substrates, and monitor for increased concentrations/toxicity, during and 2 weeks following treatment with mifepristone. Avoid cyclosporine, dihydroergotamine, ergotamine, fentanyl, pimozide, quinidine, sirolimus, and tacrolimus. 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

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

Naldemedine: P-glycoprotein/ABCB1 Inhibitors 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

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

Netupitant: May increase the serum concentration of CYP3A4 Substrates (High risk with Inhibitors). Monitor therapy

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

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

Nintedanib: Combined Inhibitors of CYP3A4 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: Antihepaciviral Combination Products 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 in patients being treated with olaparib. If such concurrent use cannot be avoided, the dose of olaparib should be reduced to 150 mg twice daily. Avoid combination

Omeprazole: Antihepaciviral Combination Products may decrease the serum concentration of Omeprazole. Monitor therapy

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

OxyCODONE: CYP3A4 Inhibitors (Strong) may enhance the adverse/toxic effect of OxyCODONE. CYP3A4 Inhibitors (Strong) may increase the serum concentration of OxyCODONE. Serum concentrations of the active metabolite oxymorphone may also be increased. Consider therapy modification

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

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. 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

P-glycoprotein/ABCB1 Substrates: P-glycoprotein/ABCB1 Inhibitors may increase the serum concentration of P-glycoprotein/ABCB1 Substrates. P-glycoprotein inhibitors may also enhance the distribution of p-glycoprotein substrates to specific cells/tissues/organs where p-glycoprotein is present in large amounts (e.g., brain, T-lymphocytes, testes, etc.). Monitor therapy

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

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

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

Pitolisant: May decrease the serum concentration of CYP3A4 Substrates (High risk with Inducers). Management: Combined use of pitolisant with a CYP3A4 substrate that has a narrow therapeutic index should be avoided. Other CYP3A4 substrates should be monitored more closely when used with pitolisant. Consider therapy modification

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

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

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

Pravastatin: Antihepaciviral Combination Products may increase the serum concentration of Pravastatin. Management: Limit the pravastatin dose to a maximum of 40 mg per day when used with antihepaciviral combination products and monitor patients for evidence of pravastatin toxicities (eg, myopathy). Consider therapy modification

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

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

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

Proguanil: Antihepaciviral Combination Products may decrease the serum concentration of Proguanil. Monitor therapy

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

Propafenone: Antihepaciviral Combination Products may increase the serum concentration of Propafenone. Management: Canadian labeling recommends avoiding this combination. Monitor therapy

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

QUEtiapine: CYP3A4 Inhibitors (Strong) may increase the serum concentration of QUEtiapine. Management: In quetiapine treated patients, reduce the quetiapine dose to one sixth of the regular dose following strong CYP3A4 inhibitor initiation. In patients receiving strong CYP3A4 inhibitors, initiate quetiapine at the lowest dose and up-titrate as needed. Consider therapy modification

QuiNIDine: Ombitasvir, Paritaprevir, and Ritonavir may increase the serum concentration of QuiNIDine. Management: Canadian labeling recommends avoiding this combination. Monitor therapy

QuiNINE: Antihepaciviral Combination Products may increase the serum concentration of QuiNINE. 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

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

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

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. Consider therapy modification

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

Rilpivirine: Antihepaciviral Combination Products may increase the serum concentration of Rilpivirine. Avoid combination

Riociguat: Antihepaciviral Combination Products may increase the serum concentration of Riociguat. Management: Consider starting with a reduced riociguat dose of 0.5 mg three times daily. Patients receiving such a combination should also be monitored closely for signs or symptoms of hypotension. Consider therapy modification

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

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

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: Saxagliptin U.S. product labeling recommends limiting saxagliptin adult dose to 2.5 mg/day when used with a strong CYP3A4 inhibitor. Monitor for increased saxagliptin levels/effects. A similar recommendation is not made in the Canadian product labeling. 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

Silodosin: P-glycoprotein/ABCB1 Inhibitors 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

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

Sirolimus: Antihepaciviral Combination Products may increase the serum concentration of Sirolimus. Avoid combination

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

Stiripentol: May increase the serum concentration of CYP3A4 Substrates (High risk with Inhibitors). Management: Use of stiripentol with CYP3A4 substrates that are considered to have a narrow therapeutic index should be avoided due to the increased risk for adverse effects and toxicity. Any CYP3A4 substrate used with stiripentol requires closer monitoring. Consider therapy modification

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

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

Tacrolimus (Systemic): Ombitasvir, Paritaprevir, and Ritonavir may increase the serum concentration of Tacrolimus (Systemic). Avoid combination

Tacrolimus (Topical): Ombitasvir, Paritaprevir, and Ritonavir may increase the serum concentration of Tacrolimus (Topical). Monitor therapy

Tadalafil: CYP3A4 Inhibitors (Strong) may increase the serum concentration of Tadalafil. Management: Recommendations regarding use of tadalafil in patients also receiving strong CYP3A4 inhibitors may vary based on indication and/or international labeling. Consult appropriate product labeling. Consider therapy modification

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

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

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

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

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: Reduce the adult dose of tofacitinib to 5 mg daily in patients receiving strong CYP3A4 inhibitors. 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: P-glycoprotein/ABCB1 Inhibitors may increase the serum concentration of Topotecan. Avoid combination

Toremifene: CYP3A4 Inhibitors (Strong) may enhance the adverse/toxic effect of Toremifene. CYP3A4 Inhibitors (Strong) may increase the serum concentration of Toremifene. Avoid combination

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

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

Triamcinolone (Systemic): Antihepaciviral Combination Products may increase the serum concentration of Triamcinolone (Systemic). Monitor therapy

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

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

Valsartan: Antihepaciviral Combination Products may increase the serum concentration of Valsartan. Management: Per antihepaciviral combination product US prescribing information, consider decreasing the valsartan dose and monitoring for evidence of hypotension and worsening renal function if these agents are used in combination. Consider therapy modification

Vardenafil: CYP3A4 Inhibitors (Strong) may increase the serum concentration of Vardenafil. Management: Recommendations regarding concomitant use of vardenafil with strong CYP3A4 inhibitors may vary depending on brand name (e.g., Levitra, Staxyn) or by international labeling. See full drug interaction monograph for details. Consider therapy modification

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

Venetoclax: CYP3A4 Inhibitors (Strong) may increase the serum concentration of Venetoclax. Management: These combinations are contraindicated during venetoclax initiation and ramp-up. In patients receiving steady venetoclax doses after completing ramp-up, reduce the venetoclax by at least 75% if strong CYP3A4 inhibitor use cannot be avoided. 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 these combinations. Consider therapy modification

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

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

Voriconazole: Antihepaciviral Combination Products may decrease the serum concentration of Voriconazole. Management: Concurrent use of voriconazole with antihepaciviral combination products should be avoided unless the patient-specific benefit/risk ratio justifies the use of voriconazole. Decreased efficacy of voriconazole is possible. Consider therapy modification

Voxilaprevir: OATP1B1/SLCO1B1 Inhibitors may increase the serum concentration of Voxilaprevir. Avoid combination

Zopiclone: CYP3A4 Inhibitors (Strong) may increase the serum concentration of Zopiclone. Management: The initial starting adult dose of zopiclone should not exceed 3.75 mg if combined with a strong CYP3A4 inhibitor. Monitor patients for signs and symptoms of zopiclone toxicity if these agents are combined. Consider therapy modification

Zuclopenthixol: CYP3A4 Inhibitors (Strong) may increase the serum concentration of Zuclopenthixol. Management: Consider zuclopenthixol dosage reduction with concomitant use of a strong CYP3A4 inhibitor (eg, ketoconazole) in poor CYP2D6 metabolizers or with strong CYP2D6 inhibitors (eg, paroxetine). Monitor for increased zuclopenthixol levels/toxicity. Consider therapy modification

Adverse Reactions

Frequency not always defined.

Central nervous system: Fatigue (7%), insomnia (5%)

Dermatologic: Allergic skin reaction (5%), pruritus (5%)

Gastrointestinal: Nausea (9%)

Hematologic & oncologic: Anemia, decreased hemoglobin

Hepatic: Increased serum ALT

Neuromuscular & skeletal: Weakness (25%)

Miscellaneous: Tachyphylaxis

<1% (Limited to important or life-threatening): Hepatic failure (in patients with underlying cirhosis; FDA Safety Alert, October 22, 2015), hypersensitivity reaction (including angioedema), liver decompensation (in patients with underlying cirrhosis; FDA Safety Alert, October 22, 2015), reactivation of HBV (FDA Safety Alert Dec. 8, 2016)

ALERT: U.S. Boxed Warning

Hepatitis B virus reactivation:

Test all patients for evidence of current or prior hepatitis B virus (HBV) infection before initiating treatment. HBV reactivation has been reported in hepatitis C virus (HCV)/HBV co-infected patients who were undergoing or had completed treatment with HCV direct acting antivirals and were not receiving HBV antiviral therapy. Some cases have resulted in fulminant hepatitis, hepatic failure, and death. Monitor HCV/HBV co-infected patients for hepatitis flare or HBV reactivation during HCV treatment and post-treatment follow-up. Initiate appropriate patient management for HBV infection as clinically indicated.

Warnings/Precautions

Concerns related to adverse effects:

• Hepatic effects: Hepatic decompensation and hepatic failure, including liver transplantation and fatal cases, have been reported with ombitasvir, paritaprevir, and ritonavir, with or without ribavirin; most patients had evidence of cirrhosis prior to treatment initiation. Typically occurs between 1 and 4 weeks of treatment initiation; characterized by acute elevation of direct bilirubin, without ALT elevation, and signs and symptoms of hepatic decompensation. Assess hepatic function (including direct bilirubin) prior to treatment initiation, during the first 4 weeks of starting treatment, and as clinically indicated; monitor patients with compensated cirrhosis for signs/symptoms of hepatic decompensation (eg, ascites, hepatic encephalopathy, variceal hemorrhage). Discontinue treatment in patients who develop signs/symptoms of hepatic decompensation.

• Hepatic enzyme elevations: Elevations of ALT (>5 times ULN) have been reported. Elevations are usually asymptomatic, occur within 4 weeks of treatment initiation, and decline within 2 to 8 weeks with continued dosing. Monitor hepatic enzymes during the first 4 weeks of treatment initiation and thereafter as clinically indicated. If ALT is elevated, repeat testing and continue to monitor closely; inform patients to contact their health care provider immediately if fatigue, weakness, lack of appetite, nausea and vomiting, jaundice, or discolored feces occur. Consider discontinuation if ALT remains persistently >10 x ULN. Discontinue if ALT increase is accompanied by signs of hepatic inflammation, elevated direct bilirubin, alkaline phosphatase, or INR. Women taking ethinyl estradiol products are at increased risk. For management of women taking concomitant estrogen products, refer to Special Populations.

Disease-related concerns:

• Hepatic impairment: Use is contraindicated in moderate to severe hepatic impairment (Child-Pugh class B or C).

• Hepatitis B virus reactivation: [US Boxed Warning]: Hepatitis B virus (HBV) reactivation has been reported in hepatitis C virus (HCV)/HBV co-infected patients who were receiving or had completed treatment with HCV direct-acting antivirals and were not receiving HBV antiviral therapy; some cases have resulted in fulminant hepatitis, hepatic failure, and death. Test all patients for evidence of current or prior HBV infection prior to initiation of treatment; monitor HCV/HBV co-infected patients for hepatitis flare or HBV reactivation during treatment and post-treatment follow-up. Initiate treatment for HBV infection as clinically indicated. HBV reactivation has been reported in HBsAg positive patients and in patients with serologic evidence of resolved HBV infection (ie, HBsAg negative and anti-HBc positive) and is characterized by an abrupt increase in HBV replication manifested as a rapid increase in serum HBV DNA level; reappearance of HBsAg may occur in patients with resolved HBV infection. Risk of HBV reactivation may be increased in patients receiving certain immunosuppressants or chemotherapeutic agents.

Concurrent drug therapy issues:

• Concomitant therapy: Contraindications of ribavirin, particularly pregnancy avoidance warnings, also apply. See ribavirin prescribing information.

• Drug-drug interactions: Potentially significant interactions may exist, requiring dose or frequency adjustment, additional monitoring, and/or selection of alternative therapy. Consult drug interactions database for more detailed information.

Special populations:

• Women taking concomitant estrogen products: Concurrent use of ethinyl estradiol-containing products is contraindicated; these products may be restarted approximately 2 weeks following completion of HCV therapy. Alternative methods of contraception (eg, nonhormonal methods, progestin-only contraception) are recommended during therapy. Women using other estrogens (eg, estradiol, conjugated estrogens) had a rate of ALT elevation similar to patients not receiving any estrogens; coadminister with caution.

Other warnings/precautions:

• Risk of HIV-1 protease inhibitor drug resistance: Ritonavir, a component of the product, is also an HIV-1 protease inhibitor. In HCV/HIV co-infected patients, ritonavir can select for HIV-1 protease inhibitor resistance-associated substitutions. Any HCV/HIV-1 co-infected patients should also be taking a suppressive antiretroviral regimen to reduce resistance risk.

Monitoring Parameters

Manufacturer’s labeling: Baseline hepatic function tests and during the first 4 weeks of therapy, then periodically during therapy, especially in patients taking efavirenz or in women taking concomitant ethinyl estradiol products; serum HCV-RNA at baseline and at the end of treatment, during treatment follow-up, and when clinically indicated.

Hepatitis B surface antigen (HBsAg) and hepatitis B core antibody (anti-HBc) prior to initiation; in patients with serologic evidence of hepatitis B virus (HBV) infection, monitor for clinical and laboratory signs of hepatitis flare or HBV reactivation during treatment and during post-treatment follow-up.

Alternate recommendations (AASLD/IDSA 2015):

Baseline (within 12 weeks prior to starting antiviral therapy): CBC, INR, hepatic function panel (albumin, total and direct bilirubin, ALT, AST, and alkaline phosphatase), calculated GFR

Baseline (at any time prior to starting antiviral therapy): HCV genotype and subtype, quantitative HCV viral load

During therapy: CBC, serum creatinine, calculated GFR, hepatic function panel (after 4 weeks of therapy and as clinically indicated); quantitative HCV viral load testing (after 4 weeks of therapy and at 12 weeks after completion of therapy). If quantitative HCV viral load is detectable at treatment week 4, repeat testing is recommended after 2 additional weeks of treatment (treatment week 6).

Pregnancy Considerations

Use of this product in combination with ribavirin is contraindicated in pregnant women and men whose female partners are pregnant.

Adverse events were not observed in animal reproduction studies using the individual agents. If used in combination with ribavirin, all warnings related to the use of ribavirin and pregnancy and/or contraception should be followed. Mother-to-child transmission of HCV does not occur if the woman is not viremic, therefore, HCV-infected women of childbearing potential should postpone pregnancy until therapy is complete. Treatment of HCV is not recommended for women who are already pregnant (AASLD/IDSA 2015).

Patient Education

• Discuss specific use of drug and side effects with patient as it relates to treatment. (HCAHPS: During this hospital stay, were you given any medicine that you had not taken before? Before giving you any new medicine, how often did hospital staff tell you what the medicine was for? How often did hospital staff describe possible side effects in a way you could understand?)

• Patient may experience nausea or insomnia. Have patient report immediately to prescriber severe loss of strength and energy, signs of liver problems (dark urine, fatigue, lack of appetite, nausea, abdominal pain, light-colored stools, vomiting, or jaundice), or signs of Stevens-Johnson syndrome/toxic epidermal necrolysis (red, swollen, blistered, or peeling skin [with or without fever]; red or irritated eyes; or sores in mouth, throat, nose, or eyes) (HCAHPS).

• Educate patient about signs of a significant reaction (eg, wheezing; chest tightness; fever; itching; bad cough; blue skin color; seizures; or swelling of face, lips, tongue, or throat). Note: This is not a comprehensive list of all side effects. Patient should consult prescriber for additional questions.

Intended Use and Disclaimer: Should not be printed and given to patients. This information is intended to serve as a concise initial reference for health care professionals to use when discussing medications with a patient. You must ultimately rely on your own discretion, experience, and judgment in diagnosing, treating, and advising patients.

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