efavirenz and Hismanal Interactions

Interactions between efavirenz and Hismanal (astemizole)

astemizole and efavirenz (Major Drug-Drug)

CONTRAINDICATED: Efavirenz inhibits the CYP450 3A4 enzyme and may interfere with the metabolism of astemizole and terfenadine. The accumulation of astemizole or terfenadine may prolong the QT interval and possibly may lead to the development of ventricular arrhythmias, including torsades de pointes.

MANAGEMENT: An alternative antihistamine should be considered for patients being treated with efavirenz.