- Carbamazepine and oxcarbazepine decrease phenytoin metabolism through inhibition of CYP2C19.
Carbamazepine and oxcarbazepine decrease phenytoin metabolism through inhibition of CYP2C19.
Epilepsy research (2002-11-30)
F Lakehal, C J Wurden, T F Kalhorn, R H Levy
PMID12458024
ABSTRACT
Multiple studies suggest that phenytoin concentrations increase with CBZ co-medication. This study evaluated the hypothesis that CBZ and/or its major metabolite (CBZE) inhibit CYP2C19-mediated phenytoin metabolism using human liver microsomes and cDNA-expressed CYP2C19. Oxcarbazepine (OXC), and its 10-monohydroxy metabolite (MHD) were also evaluated. CBZ and MHD inhibited CYP2C19-mediated phenytoin metabolism at therapeutic concentrations. Thus, administration of CBZ and OXC with CYP2C19 substrates with narrow therapeutic ranges should be done cautiously.