letairis and Biaxin xl pak Interactions

Interactions between letairis(ambrisentan) and Biaxin xl pak (clarithromycin)

clarithromycin and ambrisentan (Moderate Drug-Drug)

MONITOR: Based on in vitro data, coadministration with potent inhibitors of CYP450 3A4 and/or 2C19 may increase the plasma concentrations of ambrisentan, which has been shown to be a substrate of these isoenzymes. However, the interaction has not been studied in clinical settings.

MANAGEMENT: Because ambrisentan is associated with dose-related hepatotoxicity, concomitant use of a potent inhibitor of CYP450 3A4 (e.g., itraconazole, ketoconazole, voriconazole, nefazodone, delavirdine, protease inhibitors, ketolide and certain macrolide antibiotics) and/or 2C19 (e.g., fluconazole, fluvoxamine, omeprazole) should be approached with caution. Patients should be advised to notify their physician if they experience signs and symptoms of liver injury such as fever, rash, anorexia, nausea, vomiting, fatigue, right upper quadrant pain, dark urine, and jaundice.