the addition of phenytoin to the regimen increased steady-state plasma levels of phenobarbitone and phenylethylmalonamide ( pema ) , metabolites of primidone , and decreased levels of primidone and unconjugated p-hydroxyphenobarbitone ( p-ohpb ) , a metabolite of phenobarbitone .
C0033148
primidone
C0031412
phenobarbitone