Drug-Drug

• May ↓ levels of atazanavir and nelfinavir (avoid concurrent use with either of these antiretrovirals).
• May ↑ levels and risk of toxicity of saquinavir (may need to ↓ dose of saquinavir).
• May ↓ absorption of drugs requiring acid pH, including ketoconazole, itraconazole, atazanavir, ampicillin, and iron salts.
• May ↑ risk of bleeding with warfarin (monitor INR and PT).
• Voriconazole may ↑ levels.
• May ↓ the antiplatelet effects of clopidogrel.
• May ↑ levels of cilostazol; consider ↓ dose of cilostazol from 100 mg twice daily to 50 mg twice daily.
• Rifampin may ↓ levels and may ↓ response (avoid concurrent use).
• Hypomagnesemia ↑ risk of digoxin toxicity.
• May ↑ levels of tacrolimus.

Drug-Natural Products:

St. John's wort may ↓ levels and may ↓ response (avoid concurrent use).