Atazanavir Antacids

Drugs that may affect atazanavir include the following antacids and buffered medications, clarithromycin, didanosine (buffered formulation only), efavirenz, H2-receptor antagonists, indinavir, itraconazole, ketoconazole, nevirapine, proton pump inhibitors, rifampin, ritonavir, St. John s wort, tenofovir, voriconazole. 

NA /D, abd pain, bleeding, fevCT, T QT Interactions t Effects W7 atazanavir, clarithromycin, CT5rthromycin, indinavir, itraconazole, ketoconazole, nefazodone, nelfi-navir, ritonavir, saquinavir, telithromycin X effects W7 antacids, carbamazqjine, dexamethasone, phenobarbital, phenytoin, rifampicin, St. John s wort EMS Drug contains lactose, may cause D/abd discomfort in pts w/ lactose intolerance OD Sxs unknown symptomatic and supportive... 

Antacids or buffered medications reduce absorption of atazanavir take atazanavir 2 hr before or 1 hr after antacids or buffered medications... 

Atazanavir PI2 400 mg daily or 300 mg daily with ritonavir 100 daily. Adjust dose in hepatic insufficiency Take with food. Separate dosing from ddl or antacids by 1 h. Separate dosing from cimetidine and other acid-reducing agents by 12 h Nausea, vomiting, diarrhea, abdominal pain, headache, peripheral neuropathy, skin rash, indirect hyperbilirubinemia, prolonged PR and/or QTC interval See footnote 4 for contraindicated medications. Also avoid indinavir, irinotecan, and omeprazole. Avoid in severe hepatic insufficiency... 

Clinically important, potentially hazardous interactions with amiodarone, amprenavir, anisindione, antacids, anticoagulants, aprepitant, atazanavir, atovaquone, beclomethasone, buprenorphine, corticosteroids, cortisone, cyclosporine, cyproterone, dabigatran, dapsone, darunavir, delavirdine, dexamethasone, dicumarol, digoxin, eszopiclone, flunisolide, fosamprenavir, gadoxetate, gestrinone, halothane, imatinib, isoniazid, itraconazole, ketoconazole, lapatinib, lorcainide, methylprednisolone, midazolam, nelfinavir, nifedipine, oral contraceptives, phenylbutazone, prednisone, protease inhibitors, pyrazinamide, ramelteon, ritonavir, saquinavir, solifenacin, sunitinib, tacrolimus, telithromycin, temsirolimus, tipranavir, tolvaptan, trabectedin, triamcinolone, triazolam, voriconazole, warfarin, zaleplon... 

Proton pump inhibitors (marked effect) and H2-receptor antagonists (modest effect) reduce atazanavir levels. Other drugs that increase gastric pH are also predicted to reduce plasma levels of atazanavir. Fosamprenavir may be similarly affected (moderate effects seen with ranitidine), although antacids and esomeprazole had little effect in one study. Omeprazole decreases indinavir levels and an antacid modestly decreased tipranavir levels. Neither ranitidine nor omeprazole had any effect on darunavir/ritonavir or lopinavir/ritonavir levels. In contrast, cimetidine, ranitidine and omeprazole have been shown to increase saquinavir levels. 

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