Clinical evidence,mechanism, importance and management
The carbamazepine AUC in an epileptic patient taking carbamazepine 600mg daily was reduced by 11 % when isotretinoin 500 micrograms/kg daily,was taken, and by 24 % when 1 mg/kg daily was taken. The AUC of carbamazepine-10,11-epoxide (the active metabolite of carbamazepine) was reduced by 21 and 44 % by small and large doses of isotretinoin, respectively. The patient had no adverse effects (See reference number 1). Although author of report suggests that monitoring may be necessary in patients given both drugs changes of this magnitude, especially those seen with lower dose, are not usually clinically significant.
1. Marsden JR. Effect of isotretinoin on carbamazepine pharmacokinetics. Br J Dermatol (1988) 119,403–4.