Valproic acid pharmacokinetics in children. II. Discontinuation of concomitant antiepileptic drug therapy.
We studied the pharmacokinetics of valproic acid (VPA) in 11 children before and after discontinuance of enzyme-inducing antiepileptic drugs (AEDs). Valproic acid elimination half-life increased from 7.1 to 11.8 hours. Total and intrinsic VPA clearance decreased by approximately 40%. Valproic acid serum protein binding varied among patients from 7 to 23.8%, but was not altered by AEDs. Seizure control was maintained and mental status improved once all other AEDs were withdrawn. After discontinuation of enzyme-inducing AEDs, serum VPA concentrations can be maintained with a lower VPA dosage given less frequently.
D000293:Adolescent; D000927:Anticonvulsants / Q000494:pharmacology* / Q000627:therapeutic use; D002648:Child; D002675:Child, Preschool; D004347:Drug Interactions; D004827:Epilepsy / Q000188:drug therapy*; D005260:Female; D006801:Humans; D008297:Male; D014635:Valproic Acid / Q000494:pharmacology* / Q000627:therapeutic use
D000927:Anticonvulsants; D014635:Valproic Acid