OBJECT DRUGS

Antivirals:

• Amprenavir (Agenerase)
• Atazanavir (Reyataz)
• Darunavir (Prezista)
• Delavirdine (Rescriptor)
• Etravirine (Intelence)
• Fosamprenavir (Lexiva)
• Indinavir (Crixivan)
• Lopinavir (Kaletra)
• Maraviroc (Selzentry)
• Nelfinavir (Viracept)
• Rilpivirine (Edurant)
• Ritonavir (Norvir)
• Saquinavir (Invirase)
• Tipranavir (Aptivus)

PRECIPITANT DRUGS

Antimicrobials:

• Clarithromycin (Biaxin, etc.)
• Erythromycin (E-Mycin, etc.)
• Fluconazole (Diflucan)
• Itraconazole (Sporanox, etc.)
• Ketoconazole (Nizoral, etc.)
• Posaconazole (Noxafil)
• Quinupristin (Synercid)
• Telithromycin (Ketek)
• Troleandomycin (TAO)
• Voriconazole (Vfend)

Comment:

Inhibitors of CYP3A4 may increase the serum levels of the protease inhibitors resulting in increased side effects. Ritonavir may substantially increase voriconazole plasma concentrations, especially in patients deficient in CYP2C19.

Class 3: Assess Risk & Take Action if Necessary

• Consider Alternative:
• Azole Antifungals: Itraconazole and ketoconazole are potent inhibitors of CYP3A4; fluconazole appears weaker, but in larger doses it also inhibits CYP3A4. Terbinafine (Lamisil) does not appear to affect CYP3A4, and would not be expected to interact with protease inhibitors.
• Macrolide Antibiotics: Unlike erythromycin, clarithromycin and troleandomycin, azithromycin (Zithromax) and dirithromycin^* do not appear to inhibit CYP3A4. (^* not available in US)
• Telithromycin: The use of azithromycin (Zithromax) or a quinolone antibiotic should be considered.
• Circumvent/Minimize: Consider reducing the dose of the protease inhibitor if enzyme inhibitors are coadministered.
• Monitor: Monitor for protease inhibitor toxicity.