Interactions between cytadren(aminoglutethimide) and Cardizem cd (diltiazem)
diltiazem and aminoglutethimide (Moderate Drug-Drug)
GENERALLY AVOID: Coadministration with inducers of CYP450 3A4 may significantly decrease the plasma concentrations of diltiazem, which is primarily metabolized by the isoenzyme. In one study, coadministration with the inducer efavirenz (600 mg daily for 14 days) decreased the peak plasma concentration (Cmax), trough plasma concentration (Cmin) and systemic exposure (AUC) of diltiazem (240 mg daily for 21 days) by a mean of 60%, 63% and 69%, respectively, in 13 subjects. Rifampin, another CYP450 3A4 inducer, has been reported to lower diltiazem plasma concentrations to undetectable levels.
MANAGEMENT: Use of diltiazem with rifampin or any known CYP450 3A4 inducer should be avoided when possible, and alternative therapy considered. Diltiazem dose adjustment should be guided by clinical response if concomitant use with a CYP450 3A4 inducer is necessary.
