zafirlukast and Pimozide Interactions

Interactions between zafirlukast and Pimozide (pimozide)

pimozide and zafirlukast (Major Drug-Drug)

CONTRAINDICATED: Coadministration with inhibitors of CYP450 3A4 may increase the plasma concentrations of pimozide, which is partially metabolized by the isoenzyme. The use of pimozide has been associated with dose-related prolongation of the QT interval, thus elevated plasma levels of the drug may potentiate the risk of ventricular arrhythmias such as ventricular tachycardia and torsade de pointes as well as cardiac arrest and sudden death.

MANAGEMENT: The manufacturer considers the use of pimozide with potent CYP450 3A4 inhibitors like protease inhibitors, macrolide antibiotics, azole antifungals, and nefazodone to be contraindicated. With respect to less potent CYP450 3A4 inhibitors, the manufacturer recommends that they also not be used with pimozide.