Interactions between vardenafil and Crixivan (indinavir)
indinavir and vardenafil (Major Drug-Drug)
ADJUST DOSE: Coadministration with indinavir may significantly increase the plasma concentrations of vardenafil. The mechanism is indinavir inhibition of CYP450 3A4, the isoenzyme primarily responsible for the metabolic clearance of vardenafil. According to vardenafil labeling, coadministration of indinavir (800 mg three times a day) and vardenafil (10 mg) resulted in a 7-fold increase in the peak plasma concentration (Cmax), a 16-fold increase in the area under the concentration-time curve (AUC), and a 2-fold increase in the half-life of vardenafil. Indinavir Cmax and AUC were reduced by 40% and 30%, respectively.
MANAGEMENT: Patients treated with indinavir should not receive more than a single 2.5 mg dose of vardenafil within a 24-hour period. Patients should be advised to promptly notify their physician if they experience pain or tightness in the chest or jaw, irregular heartbeat, nausea, shortness of breath, visual disturbances, syncope, or prolonged erection (greater than 4 hours).
