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Atazanavir and Cobicistat

Pronunciation

(at a za NA veer & koe BIK i stat)

Index Terms

  • Atazanavir Sulfate/Cobicistat
  • Cobicistat and Atazanavir

Dosage Forms

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

Tablet, Oral:

Evotaz: Atazanavir 300 mg and cobicistat 150 mg

Brand Names: U.S.

  • Evotaz

Pharmacologic Category

  • Antiretroviral, Protease Inhibitor (Anti-HIV)
  • Cytochrome P-450 Inhibitor

Pharmacology

Atazanavir binds to the site of HIV-1 protease activity and inhibits 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.

Cobicistat is a mechanism-based inhibitor of cytochrome P450 3A (CYP3A). Inhibition of CYP3A-mediated metabolism by cobicistat and increases the systemic exposure of CYP3A substrates (eg, atazanavir).

Use: Labeled Indications

HIV-1 infection: Treatment of human immunodeficiency virus (HIV-1) infection in adults in combination with other antiretroviral agents.

Limitations of use: Use in treatment-experienced patients should be guided by the number of baseline primary protease inhibitor resistance substitutions

Contraindications

Hypersensitivity (previously demonstrated and clinically significant [eg, Stevens-Johnson syndrome, erythema multiforme, or toxic skin eruptions]) to atazanavir, cobicistat, or any component of the formulation; coadministration with drugs that are highly dependent on CYP3A or UGT1A1 for clearance (and for which elevated plasma concentrations of the interacting drugs are associated with serious and/or life-threatening events) or coadministration with drugs that strongly induce CYP3A and may lead to lower exposure and loss of efficacy of atazanavir or cobicistat; coadministered drugs that are contraindicated include (but are not limited to) alfuzosin, carbamazepine, cisapride, colchicine, dronedarone, ergot derivatives (dihydroergotamine, ergotamine, methylergonovine), indinavir, irinotecan, lovastatin, lurasidone, midazolam (oral), nevirapine, phenobarbital, phenytoin, pimozide, ranolazine, rifampin, sildenafil (when used for pulmonary artery hypertension), simvastatin, St John's wort, or triazolam

Canadian labeling: Additional contraindications (not in US labeling): Concurrent use with astemizole, bepridil, quinidine, ritonavir or products containing ritonavir, salmeterol, terfenadine

Dosing: Adult

Note: Dosage modifications are not possible with atazanavir/cobicistat combination tablet.

HIV-1 Infection (treatment-naive or treatment-experienced): Oral: One tablet (atazanavir 300 mg/cobicistat 150 mg) once daily. Note: Administer with other antiretroviral agents

Missed dose: If ≤12 hours, take dose as soon as possible; if >12 hours, resume at next regularly scheduled time.

Dosing: Geriatric

Refer to adult dosing. Use with caution.

Dosing: Renal Impairment

There are no dosage adjustments provided in the manufacturer's labeling.

If CrCl <70 mL/minute:

US labeling: Do not coadminister as part of a regimen that includes tenofovir disoproxil fumarate.

Canadian labeling: Not recommended as part of a regimen that includes drugs requiring dosage adjustments based on creatinine clearance (eg, emtricitabine, lamivudine, tenofovir, adefovir)

End-stage renal disease (ESRD) patients (treatment-experienced) requiring hemodialysis: Use is not recommended.

Dosing: Hepatic Impairment

Use is not recommended (has not been studied).

Administration

Oral: Administer with food. The Canadian labeling recommends that the tablet be swallowed whole and not be broken, cut, or crushed.

Dietary Considerations

Take with food.

Storage

Store at 25°C (77°F); excursions are permitted between 15°C and 30°C (59°F and 86°F).

Drug Interactions

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

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

Alfuzosin: Protease Inhibitors 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: Protease Inhibitors may increase the serum concentration of ALPRAZolam. Management: Seek alternatives to alprazolam in patients treated with HIV protease inhibitors. Concurrent use of alprazolam with indinavir is contraindicated. All patients receiving such a combination should be monitored closely for excessive response to alprazolam. Consider therapy modification

Amiodarone: Atazanavir may increase the serum concentration of Amiodarone. Monitor therapy

Amiodarone: Cobicistat may increase the serum concentration of Amiodarone. Monitor therapy

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

Amodiaquine: CYP2C8 Inhibitors may increase the serum concentration of Amodiaquine. Avoid combination

Antacids: May decrease the absorption of Atazanavir. Consider therapy modification

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

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

AtorvaSTATin: Cobicistat may increase the serum concentration of AtorvaSTATin. Management: Initiate atorvastatin at the lowest recommended dose and titrate slowly as needed while monitoring closely for evidence of atorvastatin toxicity. Consider therapy modification

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

Belinostat: Atazanavir may increase the serum concentration of Belinostat. Avoid combination

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

Boceprevir: Cobicistat may increase the serum concentration of Boceprevir. Management: Avoid concomitant use of boceprevir with cobicistat. US prescribing information for the combination product containing elvitegravir, cobicistat, emtricitabine, and tenofovir does not address this potential interaction. Avoid combination

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

Bosentan: May decrease the serum concentration of Atazanavir. Atazanavir may increase the serum concentration of Bosentan. Management: Concurrent use of atazanavir (without ritonavir) and bosentan is not recommended. Bosentan dose adjustments are required when used together with atazanavir/ritonavir. Consider therapy modification

Bosentan: Cobicistat may increase the serum concentration of Bosentan. Management: See full drug interaction monograph for details. Consider therapy modification

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

Bosutinib: P-glycoprotein/ABCB1 Inhibitors 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

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): Cobicistat may increase the serum concentration of Budesonide (Nasal). Management: Consider an alternative nasal corticosteroid when possible, particularly for longer-term concurrent use. If this combination must be used, monitor patients closely for evidence of systemic corticosteroid effects including adrenal suppression. Consider therapy modification

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: May decrease the serum concentration of Atazanavir. Atazanavir may increase the serum concentration of Buprenorphine. Management: Avoid this combination in patients un-boosted atazanavir due to possible decreased atazanavir concentrations. This combination is not contraindicated in patients also receiving ritonavir, but monitoring for buprenorphine toxicity is recommended. Avoid combination

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

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

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

CarBAMazepine: May decrease the serum concentration of Cobicistat. Avoid combination

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

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: Cobicistat may increase the serum concentration of Cisapride. Avoid combination

Clarithromycin: May increase the serum concentration of Cobicistat. Cobicistat may increase the serum concentration of Clarithromycin. Management: Consider alternative antibiotics. Reduce clarithromycin dose by 50% in patients receiving elvitegravir/cobicistat/emtricitabine/tenofovir with estimated creatinine clearance 50 to 60 mL/min. Closely monitor for clarithromycin toxicity. Consider therapy modification

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

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

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. 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-glycoprotein inhibitor. In those with normal renal and hepatic function, reduce colchicine dose as directed. Consider therapy modification

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

Conivaptan: May increase the serum concentration of CYP3A4 Substrates. Avoid combination

Contraceptives (Estrogens): Cobicistat may decrease the serum concentration of Contraceptives (Estrogens). Management: Consider an alternative, non-hormone-based contraceptive in patients receiving cobicistat-containing products. Consider therapy modification

Contraceptives (Progestins): Cobicistat may increase the serum concentration of Contraceptives (Progestins). Management: Consider an alternative, non-hormone-based contraceptive in patients receiving cobicistat-containing products. Consider therapy modification

Contraceptives (Progestins): Atazanavir may increase the serum concentration of Contraceptives (Progestins). However, atazanavir may lead to decreased ethinyl estradiol concentrations and decreased effectiveness of oral contraceptive products. Management: Consider an alternative or additional method of contraception, particularly with combined estrogen/progestin products. Depot medroxyprogesterone acetate may be used without a need for additional contraception. 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

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

CycloSPORINE (Systemic): Protease Inhibitors may increase the serum concentration of CycloSPORINE (Systemic). CycloSPORINE (Systemic) may increase the serum concentration of Protease Inhibitors. Consider therapy modification

CYP2D6 Substrates: Cobicistat may increase the serum concentration of CYP2D6 Substrates. Monitor therapy

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

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

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

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

CYP3A4 Substrates: CYP3A4 Inhibitors (Strong) may decrease the metabolism of CYP3A4 Substrates. 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

Dapsone (Systemic): May enhance the adverse/toxic effect of Atazanavir. Specifically, the risk of hyperbilirubinemia may be increased. Monitor therapy

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. Monitor therapy

Delavirdine: Protease Inhibitors may decrease the serum concentration of Delavirdine. Delavirdine may increase the serum concentration of Protease Inhibitors. Consider therapy modification

Dexamethasone (Systemic): May decrease the serum concentration of Cobicistat. Dexamethasone (Systemic) may also counteract the boosting effects of Cobicistat on some agents. Management: Consider an alternative corticosteroid. Monitor patients receiving this combination closely for evidence of diminished response to the antiviral regimen. Consider therapy modification

Didanosine: May decrease the serum concentration of Atazanavir. Specifically, the buffered formulation of didanosine may decrease atazanavir absorption. Atazanavir may decrease the serum concentration of Didanosine. Reported with enteric coated didanosine capsules. Management: To avoid therapeutic failure of atazanavir the drug should be administered 2 hours before or 1 hour after didanosine. This recommendation applies to both buffered didanosine products and enteric coated didanosine products. Consider therapy modification

Digoxin: Protease Inhibitors may increase the serum concentration of Digoxin. Increased serum concentrations of digoxin may increase risk of AV nodal blockade. Monitor therapy

Dihydroergotamine: Cobicistat may increase the serum concentration of Dihydroergotamine. Avoid combination

Disulfiram: Atazanavir may diminish the therapeutic effect of Disulfiram. 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

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

Efavirenz: May decrease the serum concentration of Atazanavir. Management: When used with efavirenz, the adult atazanavir dose should be 400 mg daily, boosted with ritonavir 100 mg daily or cobicistat 150 mg daily, for treatment-naive patients only; treatment-experienced patients should not use atazanavir with efavirenz. Consider therapy modification

Elbasvir: Cobicistat may increase the serum concentration of Elbasvir. Avoid combination

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

Elvitegravir: Atazanavir may increase the serum concentration of Elvitegravir. Specifically, atazanavir/ritonavir may increase the concentration of elvitegravir. Management: When elvitegravir is combined with atazanavir/ritonavir, the dose of elvitegravir should be reduced to 85 mg once daily and the dose of atazanavir/ritonavir should be 300 mg/100 mg once daily. Avoid the use of atazanavir/cobicistat and elvitegravir. Consider therapy modification

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

Enzalutamide: May decrease the serum concentration of CYP3A4 Substrates. 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

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

Ergotamine: Cobicistat may increase the serum concentration of Ergotamine. 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

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

Etravirine: Atazanavir may increase the serum concentration of Etravirine. Etravirine may decrease the serum concentration of Atazanavir. Management: The combination of etravirine and atazanavir should be avoided unless atazanavir is boosted with ritonavir. The use of cobicistat instead of ritonavir has not been evaluated and is not recommended. Consider therapy modification

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

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

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

Fluticasone (Nasal): Cobicistat may increase the serum concentration of Fluticasone (Nasal). Management: Consider an alternative nasal corticosteroid when possible, particularly for longer-term concurrent use. Consider therapy modification

Fluticasone (Oral Inhalation): Cobicistat may increase the serum concentration of Fluticasone (Oral Inhalation). Avoid combination

Fluvastatin: Atazanavir may increase the serum concentration of Fluvastatin. Consider therapy modification

Fosamprenavir: Cobicistat may increase the serum concentration of Fosamprenavir. However, the magnitude of this change is unclear, and dosing recommendations for this combination are not available. Avoid combination

Fosphenytoin-Phenytoin: May decrease the serum concentration of Cobicistat. Avoid combination

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

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

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

Grazoprevir: Cobicistat 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

H2-Antagonists: May decrease the serum concentration of Atazanavir. Management: Specific dose limitations and administration guidelines exist; consult full interaction monograph or atazanavir prescribing information. Consider therapy modification

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

Highest Risk QTc-Prolonging Agents: QTc-Prolonging Agents (Indeterminate Risk and Risk Modifying) may enhance the QTc-prolonging effect of Highest Risk QTc-Prolonging Agents. Management: Avoid such combinations when possible. Use should be accompanied by close monitoring for evidence of QT prolongation or other alterations of cardiac rhythm. Consider therapy modification

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: If a strong CYP3A inhibitor must be used short-term (e.g. antifungals and antibiotics for 7 days or less), consider stopping ibrutinib until the CYP3A inhibitor is no longer needed. Avoid combination

Idelalisib: May increase the serum concentration of CYP3A4 Substrates. 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

Indinavir: Atazanavir may enhance the adverse/toxic effect of Indinavir. Indinavir may enhance the adverse/toxic effect of Atazanavir. Avoid combination

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

Itraconazole: May increase the serum concentration of Cobicistat. Cobicistat may increase the serum concentration of Itraconazole. Management: Limit itraconazole to a maximum adult dose of 200 mg/day in patients treated with the elvitegravir/cobicistat/emtricitabine/tenofovir combination product. Dosing recommendations for other cobicistat-containing products are not available. 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 prescribing information 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): May increase the serum concentration of Cobicistat. Cobicistat may increase the serum concentration of Ketoconazole (Systemic). Management: Limit ketoconazole to a maximum adult dose of 200 mg/day in patients being treated with the elvitegravir/cobicistat/emtricitabine/tenofovir combination product. Dosing recommendations for other cobicistat-containing products are not available. Consider therapy modification

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

LamoTRIgine: Atazanavir may decrease the serum concentration of LamoTRIgine. 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

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

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

Luliconazole: May increase the serum concentration of CYP3A4 Substrates. 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

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

Meperidine: Protease Inhibitors may enhance the adverse/toxic effect of Meperidine. Protease Inhibitors may decrease the serum concentration of Meperidine. Concentrations of the toxic Normeperidine metabolite may be increased. Consider therapy modification

Methylergonovine: Cobicistat may increase the serum concentration of Methylergonovine. 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

Midazolam: Cobicistat may increase the serum concentration of Midazolam. Management: Oral midazolam use is contraindicated with cobicistat-containing products. IV midazolam should be used with caution, close monitoring, and consideration of lower IV midazolam doses. Avoid combination

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 300 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. 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

MiFEPRIStone: May enhance the QTc-prolonging effect of QTc-Prolonging Agents (Indeterminate Risk and Risk Modifying). Management: Though the drugs listed here have uncertain QT-prolonging effects, they all have some possible association with QT prolongation and should generally be avoided when possible. Consider therapy modification

Minocycline: May decrease the serum concentration of Atazanavir. Monitor therapy

Minoxidil (Systemic): Atazanavir may increase the serum concentration of Minoxidil (Systemic). Monitor therapy

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

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

Moderate Risk QTc-Prolonging Agents: QTc-Prolonging Agents (Indeterminate Risk and Risk Modifying) may enhance the QTc-prolonging effect of Moderate Risk QTc-Prolonging Agents. 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

Netupitant: May increase the serum concentration of CYP3A4 Substrates. Monitor therapy

Nevirapine: Atazanavir may increase the serum concentration of Nevirapine. Nevirapine may decrease the serum concentration of Atazanavir. Avoid combination

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

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

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

Ombitasvir, Paritaprevir, Ritonavir, and Dasabuvir: Atazanavir may increase the serum concentration of Ombitasvir, Paritaprevir, Ritonavir, and Dasabuvir. Specifically, the paritaprevir component may increase significantly. Management: These agents can be combined if the atazanavir dose is 300 mg daily, atazanavir is administered in the morning at the same time as the ombitasvir/paritaprevir/ritonavir/dasabuvir combination product, and atazanavir is given without additional ritonavir. Consider therapy modification

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

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

OXcarbazepine: May decrease the serum concentration of Cobicistat. Management: Consider an alternative antiepileptic when possible. Consider therapy modification

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

PACLitaxel (Conventional): Atazanavir may increase the serum concentration of PACLitaxel (Conventional). Management: Use of paclitaxel or other narrow therapeutic index CYP2C8 substrates with atazanavir without concurrent ritonavir is not recommended. If paclitaxel is used with ritonavir-boosted atazanavir, no significant interaction is expected. Avoid combination

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

Perhexiline: CYP2D6 Inhibitors (Weak) may increase the serum concentration of Perhexiline. Monitor therapy

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

PHENobarbital: May decrease the serum concentration of Cobicistat. Avoid combination

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

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

Pitavastatin: Atazanavir may increase the serum concentration of Pitavastatin. 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 Atazanavir. Monitor therapy

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

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

Primidone: May decrease the serum concentration of Cobicistat. Avoid combination

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

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

Proton Pump Inhibitors: May decrease the serum concentration of Atazanavir. Management: See full drug interaction monograph for details. Consider therapy modification

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: Atazanavir may increase the serum concentration of QuiNIDine. Monitor therapy

QuiNIDine: Cobicistat may increase the serum concentration of QuiNIDine. Monitor therapy

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: Atazanavir may increase the serum concentration of Repaglinide. Management: Use of repaglinide or other narrow therapeutic index CYP2C8 substrates with atazanavir without concurrent ritonavir is not recommended. If repaglinide is used with ritonavir-boosted atazanavir, no significant interaction is expected. Avoid combination

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

Rifabutin: Atazanavir may increase serum concentrations of the active metabolite(s) of Rifabutin. Atazanavir may increase the serum concentration of Rifabutin. Management: Reduce rifabutin doses. Atazanavir US labeling recommends a decrease of at least 75%, to 150 mg every other day or 3 times per week for adults. Clinical guidelines recommend 150 mg/day or 300 mg 3 times per week with atazanavir/ritonavir. Consider therapy modification

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

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

Rifapentine: May decrease the serum concentration of Cobicistat. Avoid combination

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

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

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

Ritonavir: 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

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

Rosiglitazone: Atazanavir may increase the serum concentration of Rosiglitazone. Monitor therapy

Rosuvastatin: Protease Inhibitors may increase the serum concentration of Rosuvastatin. Management: Start at the lowest rosuvastatin dose and monitor for toxicity. See full drug interaction monograph for details. Consider therapy modification

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

Saquinavir: Cobicistat may increase the serum concentration of Saquinavir. However, the magnitude of this change is unclear, and dosing recommendations for this combination are not available. Avoid combination

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: 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

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

Siltuximab: May decrease the serum concentration of CYP3A4 Substrates. 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

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 decrease the serum concentration of Cobicistat. Avoid combination

St John's Wort: May decrease the serum concentration of Atazanavir. Avoid combination

Stiripentol: May increase the serum concentration of CYP3A4 Substrates. 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

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

Tacrolimus (Systemic): Protease Inhibitors may decrease the metabolism of Tacrolimus (Systemic). Consider therapy modification

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

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

Tadalafil: Cobicistat may increase the serum concentration of Tadalafil. Management: Recommendations for use of tadalafil in patients also receiving cobicistat vary by tadalafil indication and country. See full drug interaction monograph for details. 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

Telaprevir: Cobicistat may increase the serum concentration of Telaprevir. Management: Avoid concomitant use of telaprevir with cobicistat. This warning does not apply to use of the combination product containing elvitegravir, cobicistat, emtricitabine, and tenofovir. Avoid combination

Telithromycin: May increase the serum concentration of Cobicistat. Cobicistat may increase the serum concentration of Telithromycin. Management: Seek alternatives to telithromycin. US prescribing information for the combination product containing elvitegravir, cobicistat, emtricitabine, and tenofovir does not address this potential interaction. Consider therapy modification

Temsirolimus: Protease Inhibitors may enhance the adverse/toxic effect of Temsirolimus. Levels of sirolimus, the active metabolite, may be increased, likely due to inhibition of CYP-mediated metabolism. Consider therapy modification

Tenofovir Disoproxil Fumarate: May decrease the serum concentration of Atazanavir. Atazanavir may increase the serum concentration of Tenofovir Disoproxil Fumarate. Management: Must use ritonavir-boosting in adults; give combo (atazanavir/ritonavir 300mg/100mg and tenofovir 300mg) as a single daily dose with food. Pediatric patients, pregnant patients, and users of H2-blockers require other dose changes. Consider therapy modification

Tenofovir Products: Cobicistat may enhance the adverse/toxic effect of Tenofovir Products. More specifically, cobicistat may impair proper tenofovir monitoring and dosing. Monitor therapy

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

Theophylline Derivatives: Protease Inhibitors may decrease the serum concentration of Theophylline Derivatives. Exceptions: Dyphylline. 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: Cobicistat may increase the serum concentration of Tipranavir. However, the magnitude of this change is unclear, and dosing recommendations for this combination are not available. Avoid combination

TiZANidine: CYP1A2 Inhibitors (Weak) may increase the serum concentration of TiZANidine. Management: Avoid these combinations when possible. If combined use cannot be avoided, initiate tizanidine at an adult dose of 2 mg and increase in 2-4 mg increments based on patient response. Monitor for increased effects of tizanidine, including adverse reactions. Consider therapy modification

Tocilizumab: May decrease the serum concentration of CYP3A4 Substrates. 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

TraZODone: Atazanavir may increase the serum concentration of TraZODone. Management: Consider using a lower dose of trazodone when used in combination with atazanavir. Consider therapy modification

Triazolam: Cobicistat 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

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

Vardenafil: Cobicistat may increase the serum concentration of Vardenafil. Management: Recommendations regarding use of vardenafil with cobicistat-containing products vary by vardenafil product and by country. 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: Atazanavir may decrease the serum concentration of Voriconazole. Atazanavir may increase the serum concentration of Voriconazole. Voriconazole may decrease the serum concentration of Atazanavir. Management: Voriconazole should not be used in a patient who is being treated with ritonavir-boosted atazanavir unless the benefits of the combination outweigh the potential risks. Extra monitoring for both loss of effectiveness and toxicity is warranted. Avoid combination

Warfarin: Atazanavir may increase the serum concentration of Warfarin. Monitor therapy

Warfarin: Cobicistat may increase the serum concentration of Warfarin. Monitor therapy

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

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

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

Test Interactions

Refer to individual monographs.

Adverse Reactions

Frequency not always defined.

>10%:

Hepatic: Abnormal bilirubin levels (65%; >2.5 × ULN), jaundice (13%; grades 2 to 4: 5%)

Ophthalmic: Scleral icterus (15%; grades 2 to 4: 3%)

1% to 10%:

Cardiovascular: First-degree atrioventricular block (6%; asymptomatic), cardiac conduction disturbance (including but not limited to P-R interval prolongation and second degree atrioventricular block)

Central nervous system: Abnormal dreams (grades ≥2: <2%), depression (grades ≥2: <2%), fatigue (grades ≥2: <2%), headache (grades ≥2: <2%), insomnia (grades ≥2: <2%)

Dermatologic: Skin rash (5%; erythema multiforme, maculopapular rash, eosinophilia, and DRESS syndrome), Stevens-Johnson syndrome

Endocrine & metabolic: Glycosuria (3%; ≥1,000 mg/dL), increased gamma-glutamyl transferase (2%; >5.0 × ULN), Fanconi's syndrome (grades ≥2: <2%), buffalo hump, cushingoid appearance, increased HDL cholesterol, increased LDL cholesterol, increased serum cholesterol, increased serum triglycerides, truncal obesity

Gastrointestinal: Nausea (12%; grades 3/4: 2%), diarrhea (11%; grades ≥2: <2%), increased serum lipase (grades 3/4: 9%), increased serum amylase (4%; >2.0 × ULN), upper abdominal pain (grades ≥2: <2%), vomiting (grades ≥2: <2%)

Genitourinary: Hematuria (3%; >75 RBC/HPF), breast hypertrophy

Hematologic & oncologic: Hemorrhage (increased spontaneous bleeding in patients with hemophilia)

Hepatic: Increased serum ALT (3%; >5.0 × ULN), increased serum AST (3%; >5.0 × ULN), hepatotoxicity (in patients with hepatitis)

Immunologic: Immune reconstitution syndrome

Neuromuscular & skeletal: Increased creatine phosphokinase (5%; ≥10.0 × ULN), rhabdomyolysis (<2%), amyotrophy, lipoatrophy

Renal: Nephrolithiasis (2%), renal disease (grades ≥2: <2%), acute renal failure, decreased creatinine clearance, increased serum creatinine, renal insufficiency

<1% (Limited to important or life-threatening): Cholelithiasis, diabetes mellitus (new onset and exacerbation), hyperglycemia

Warnings/Precautions

Concerns related to adverse effects:

• Cholelithiasis: Cases have been reported postmarketing; some required hospitalization and some had complications. Temporary or permanent discontinuation of therapy should be considered if symptoms develop.

• Elevated bilirubin: Asymptomatic elevations in bilirubin (unconjugated) occur commonly during therapy; reversible upon discontinuation. Safety data does not exist for bilirubin persistently >5 times ULN. Evaluate alternative etiologies if transaminase elevations also occur. Consider alternative therapy if jaundice or scleral icterus cause cosmetic concern.

• Fat redistribution: May cause redistribution of fat (eg, buffalo hump, peripheral wasting with increased abdominal girth, cushingoid appearance).

• Hypersensitivity reactions: Protease inhibitors have been associated with a variety of hypersensitivity events (some severe), including rash, anaphylaxis (rare), angioedema, bronchospasm, erythema multiforme, Stevens-Johnson syndrome (rare), acute generalized exanthematous pustulosis, toxic epidermal necrolysis, and/or drug rash with eosinophilia and systemic symptoms (DRESS) syndrome. Discontinue treatment if severe skin reactions develop. Severe skin reactions may be accompanied by fever, malaise, fatigue, arthralgias, hepatitis, oral lesions, blisters, conjunctivitis, and/or eosinophilia. Mild to moderate rash may occur early in treatment and resolve with continued therapy.

• 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.

• Nephrolithiasis: Cases have been reported postmarketing; some required hospitalization and some had complications. Temporary or permanent discontinuation of therapy should be considered if symptoms develop.

• Renal toxicity: Concomitant use of cobicistat and tenofovir may cause renal toxicity (acute renal failure and/or Fanconi syndrome); avoid use with concurrent or recent nephrotoxic therapy. Calculate estimated creatinine clearance (CrCl) prior to initiation of therapy. Assess serum phosphorus in patients with or at risk for renal impairment. In patients receiving concomitant tenofovir, assess urine glucose and urine protein prior to and periodically during treatment and monitor renal function (including recalculation of creatinine clearance) during therapy. Do not administer in combination with tenofovir in patients with CrCl <70 mL/minute. The Canadian labeling recommends avoiding therapy initiation in patients with CrCl <70 mL/minute who are receiving agents that require dose adjustment based on creatinine clearance (eg, emtricitabine, lamivudine, tenofovir, adefovir).

Disease-related concerns:

• Conduction abnormalities: Atazanavir may prolong PR interval; usually first degree AV block only and asymptomatic; rare cases of second-degree AV block have been reported. ECG monitoring should be considered in patients with preexisting conduction abnormalities or with medications which prolong AV conduction (dosage adjustment required with some agents).

• Diabetes: Changes in glucose tolerance, hyperglycemia, exacerbation of diabetes, DKA, and new-onset diabetes mellitus have been reported in patients receiving protease inhibitors. Initiation or dose adjustments of antidiabetic agents may be required.

• Hemophilia A or B: Use with caution in patients with hemophilia A or B; increased bleeding (eg, spontaneous skin hematomas and hemarthroses) has been reported during protease inhibitor therapy. Some patients receive additional factor VIII. In more than half of the cases, protease inhibitor treatment was continued or reintroduced if treatment was discontinued.

• Hepatic impairment: Not recommended in patients with hepatic impairment. Patients with underlying hepatic disease such as hepatitis B or C or marked transaminase elevations may be at risk for further transaminase elevations or hepatic decompensation. Closely monitor at risk patients at baseline and periodically during treatment.

• Renal impairment: Not recommended for use in treatment-experienced patients with end stage renal disease (ESRD) on hemodialysis.

Concurrent drug therapy issues:

• Concurrent therapy: Avoid use with other protease inhibitors, elvitegravir, ritonavir, or other atazanavir- or cobicistat-containing products.

• 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.

Other warning/precautions:

• Appropriate use: Do not use atazanavir and cobicistat plus abacavir/lamivudine in adolescent and adult HIV-1 patients with a pre-ART HIV RNA >100,000 copies/mL (HHS [adult] 2015).

• False elevations in serum creatinine: Cobicistat may inhibit tubular secretion of creatinine without affecting actual renal glomerular function; use caution when interpreting serum creatinine values in patients with medical conditions or receiving drugs needing to be monitored with estimated CrCl. Patients who experience a confirmed increase in serum creatinine >0.4 mg/dL from baseline should have renal function monitored closely. Assess estimated CrCl prior to initiating therapy; consider alternative medications that do not require dosage adjustments in patients with renal impairment.

Monitoring Parameters

Vital signs, ECG, serum creatinine (at baseline and when clinically indicated); liver function tests (baseline and periodically during treatment) in patients at risk for hepatic impairment. When coadministered with tenofovir, serum creatinine, urine glucose, and urine protein prior to initiation and as clinically indicated during therapy; assess serum phosphorus in patients with or at risk for renal impairment. Patients who experience a confirmed increase in serum creatinine >0.4 mg/dL from baseline should have renal function monitored closely. Testing for HBV is recommended prior to the initiation of antiretroviral therapy.

Pregnancy Risk Factor

B

Pregnancy Considerations

Adverse events were not observed in animal reproduction studies with atazanavir or cobicistat.

The HHS Perinatal HIV Guidelines note there are insufficient data to recommend this combination for routine use in antiretroviral-naive pregnant women (HHS [perinatal] 2016). See individual agents.

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 diarrhea. Have patient report immediately to prescriber signs of liver problems (dark urine, fatigue, lack of appetite, nausea, abdominal pain, light-colored stools, vomiting, or jaundice), signs of high blood sugar (confusion, fatigue, increased thirst, increased hunger, polyuria, flushing, fast breathing, or breath that smells like fruit), signs of kidney problems (urinary retention, hematuria, change in amount of urine passed, or weight gain), dizziness, passing out, muscle pain, joint pain, painful urination, back pain, abdominal pain, hematuria, abnormal heartbeat, severe nausea, severe vomiting, change in body fat, jaundice, 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), or signs of infection (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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