e-mycin and D h e 45 Interactions

Interactions between e-mycin(erythromycin) and D h e 45 (dihydroergotamine)

erythromycin and dihydroergotamine (Major Drug-Drug)

CONTRAINDICATED: Coadministration with certain macrolide antibiotics may significantly increase the plasma concentrations of ergot derivatives. The mechanism is macrolide inhibition of CYP450 3A4, the isoenzyme responsible for the metabolic clearance of ergotamine and related drugs. Macrolides that may significantly inhibit CYP450 3A4 include clarithromycin, erythromycin and troleandomycin, and clinical ergotism has been reported in patients receiving ergotamine or dihydroergotamine with these agents. Azithromycin and dirithromycin are generally believed to have little, if any, effect on CYP450 3A4.

MANAGEMENT: Given the potential for ergot toxicity characterized by peripheral vasospasm, ischemia, thrombosis, tachycardia and hypertension, concomitant use of ergot derivatives with clarithromycin, erythromycin, or troleandomycin is considered contraindicated. Although clinical data have not been reported, some manufacturers also consider the combination of cabergoline with macrolides contraindicated or to be avoided on theoretical grounds. Azithromycin may be a safer alternative during therapy with ergot derivatives.