Differential effect of cimetidine on serum concentrations of carbamazepine and phenytoin.
Cimetidine is an inhibitor of drug metabolism. We studied the effects of cimetidine (1,200 mg/d) on steady-state serum concentrations of carbamazepine and phenytoin in 11 epileptic volunteers. The mean serum carbamazepine concentration was unchanged after 7 days of cimetidine treatment. Five subjects were taking phenytoin concurrently; their mean serum phenytoin concentration was significantly increased after 7 and 10 days of cimetidine treatment and returned to baseline 2 weeks after cimetidine was discontinued. Cimetidine apparently inhibits the clearance of phenytoin but not of carbamazepine in adults on chronic therapy.
D000293:Adolescent; D000328:Adult; D002220:Carbamazepine / Q000097:blood* / Q000627:therapeutic use; D004347:Drug Interactions; D004359:Drug Therapy, Combination; D004827:Epilepsy / Q000097:blood / Q000188:drug therapy*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D010672:Phenytoin / Q000097:blood* / Q000627:therapeutic use
D002220:Carbamazepine; D010672:Phenytoin