Interactions between fortovase(saquinavir) and Cisapride (cisapride)
cisapride and saquinavir (Major Drug-Drug)
CONTRAINDICATED: Coadministration with protease inhibitors (PIs), particularly ritonavir, may significantly increase the plasma concentrations of cisapride. The mechanism is PI inhibition of CYP450 3A4, the isoenzyme responsible for the metabolic clearance of cisapride. Although the interaction has not been specifically studied with any of the available PIs, high plasma levels of cisapride have been associated with prolongation of the QT interval on the ECG; ventricular arrhythmias including ventricular tachycardia, ventricular fibrillation, and torsade de pointes; cardiac arrest; and sudden death.
MANAGEMENT: Given the potential for serious and life-threatening adverse cardiac events associated with increased plasma levels of cisapride, the concomitant use with protease inhibitors is considered contraindicated.
