the phenobarbital/primidone ratio ( mean 0.84 ) and pema/primidone ratio ( mean 0.56 ) in pregnant patients were found to be lower than in non-pregnant patients , except when primidone was given in combination with phenytoin in which case the expected phenobarbital/primidone ( mean 2.5 ) and pema/primidone ( mean 1.5 ) ratios were found .
C0031412
phenobarbital
C0033148
primidone