The effect of concurrent administration of sodium valproate on serum levels of primidone and its metabolite phenobarbital.
The effect of associated therapy on serum primidone (PRM) and derived phenobarbital (PB) concentrations, and on serum concentrations to PRM dose ratios (L/D ratio) were evaluated retrospectively from 100 consecutive PRM and derived PB determinations in 100 chronically treated epileptic patients. PRM administered was significantly (P less than 0.01) correlated with both serum PRM (r = 0.799 approximately 0.933) and derived PB levels (r = 0.545 approximately 0.870) in patients taking PRM. Derived PB L/D ratios and PB/PRM concentration ratios were higher in patients taking PRM in combination with phenytoin (PHT) and/or sodium valproate (VPA). Therefore, serum levels of PRM and derived PB should be monitored closely in patients taking PRM with PHT and/or VPA.
Yukawa
E
E
Department of Hospital Pharmacy, Kyushu University Hospital, Faculty of Medicine, Fukuoka, Japan.
Higuchi
S
S
Aoyama
T
T
D000293:Adolescent; D000328:Adult; D002648:Child; D002675:Child, Preschool; D004347:Drug Interactions; D004359:Drug Therapy, Combination; D004827:Epilepsy / Q000188:drug therapy; D006801:Humans; D008875:Middle Aged; D010634:Phenobarbital / Q000097:blood*; D011324:Primidone / Q000008:administration & dosage / Q000097:blood*; D012189:Retrospective Studies; D014635:Valproic Acid / Q000008:administration & dosage / Q000494:pharmacology*
D011324:Primidone; D014635:Valproic Acid; D010634:Phenobarbital