efavirenz and Dihydroergotamine Interactions

Interactions between efavirenz and Dihydroergotamine (dihydroergotamine)

dihydroergotamine and efavirenz (Major Drug-Drug)

CONTRAINDICATED: Coadministration with efavirenz may increase the plasma concentrations of ergot derivatives. The mechanism is efavirenz inhibition of CYP450 3A4, the isoenzyme responsible for the metabolic clearance of ergotamine and related drugs.

MANAGEMENT: Given the potential for ergot toxicity characterized by peripheral vasospasm, ischemia, thrombosis, tachycardia and hypertension, concomitant use of ergot derivatives with efavirenz is considered contraindicated.