Valproic acid and plasma levels of phenytoin.
Eight patients were treated concurrently with a constant dose of phenytoin and valproic acid for 1 year. During initial therapy with valproic acid, total plasma phenytoin levels decreased. The interaction was transient and was not observed at the end of 1 year. Total plasma phenytoin levels returned to pre-valproic-acid levels in seven patients.
D004347:Drug Interactions; D004359:Drug Therapy, Combination; D006801:Humans; D010672:Phenytoin / Q000097:blood* / Q000627:therapeutic use; D014635:Valproic Acid / Q000097:blood / Q000627:therapeutic use*
D014635:Valproic Acid; D010672:Phenytoin