OBJECT DRUGS
Antivirals:
- Amprenavir (Agenerase)
- Atazanavir (Reyataz)
- Daclatasvir (Daklinza)
- Darunavir (Prezista)
- Delavirdine (Rescriptor)
- Etravirine (Intelence)
- Fosamprenavir Lexiva
- Indinavir (Crixivan)
- Lopinavir (Kaletra)
- Maraviroc (Selzentry)
- Nelfinavir (Viracept)
- Rilpivirine (Edurant)
- Ritonavir (Norvir)
- Saquinavir (Invirase)
- Telaprevir (Incivek)
PRECIPITANT DRUGS
Antimicrobials:
- Ciprofloxacin (Cipro, etc.)
- 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 antivirals 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 these antivirals.
- 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 other than ciprofloxacin should be considered.
- Circumvent/Minimize: Consider reducing the dose of the antiviral if enzyme inhibitors are coadministered.
- Monitor:Monitor for antiviral toxicity.