Interactions between efavirenz and Pimozide (pimozide)
pimozide and efavirenz (Major Drug-Drug)
CONTRAINDICATED: Coadministration with efavirenz may increase the plasma concentrations of pimozide. The proposed mechanism is competitive inhibition of pimozide metabolism via CYP450 3A4. Elevated plasma levels of pimozide 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 pimozide, the concomitant use of efavirenz is considered contraindicated.
