Drug Interaction Report

MONITOR: Coadministration with inducers of CYP450 3A4 may decrease the plasma concentrations of pimavanserin, which is primarily metabolized by the isoenzyme. A drug interaction study has shown decreases in pimavanserin Cmax (71%) and AUC (91%) with coadministration of rifampin, a strong CYP450 3A4 inducer. A physiologically based pharmacokinetic simulation with a moderate CYP450 3A4 inducer (efavirenz) predicted Cmax and AUC of pimavanserin will be decreased by approximately 60% and 70%, respectively.

MANAGEMENT: The possibility of diminished therapeutic response to pimavanserin should be considered during coadministration with CYP450 3A4 inducers. The manufacturer recommends coadministration with strong or moderate CYP450 3A4 inducers be avoided.