Inhibition by erythromycin of the conversion of carbamazepine to its active 10,11‐epoxide metabolite.

Abstract

The serum levels of carbamazepine (CBZ) and its 10,11‐epoxide metabolite (CBZ‐E) were determined in seven subjects after a single dose of CBZ (400 mg) in the control state and during co‐administration of erythromycin (500 mg three times daily for 10 days). Erythromycin treatment was associated with a decrease in CBZ clearance and a prolongation of CBZ half‐life, while CBZ‐E levels were markedly reduced. These data provide evidence that erythromycin inhibits the conversion of CBZ to its epoxide metabolite. 1987 The British Pharmacological Society