Interactions between propecia(finasteride) and Priftin (rifapentine)
finasteride and rifapentine (Moderate Drug-Drug)
MONITOR: Coadministration with rifapentine may decrease the plasma concentrations of drugs that are substrates of the CYP450 2C8, 2C9, and/or 3A4 isoenzymes. The mechanism is accelerated clearance due to induction of those isoenzymes by rifapentine. Enzyme activities may be induced within 4 days of the first dose and return to normal 14 days after discontinuation of rifapentine. In vitro and in vivo enzyme studies have suggested rifapentine induction potential to be less than that of rifampin but greater than that of rifabutin. In addition, the magnitude of induction is dependent on dose and dosing frequency.
MANAGEMENT: When drugs that are known substrates of CYP450 2C8, 2C9, and/or 3A4 are coadministered with rifapentine, the possibility of a diminished therapeutic response to those drugs should be considered. Dosage adjustments as well as clinical and laboratory monitoring may be appropriate for some drugs, particularly those with a narrow therapeutic range, whenever rifapentine is added to or withdrawn from therapy.
