Changes in primidone/phenobarbitone ratio during pregnancy and the puerperium.
Plasma concentrations of primidone and its metabolite phenobarbitone were monitored in 9 pregnant epileptic patients treated with primidone (and in 3 cases other antiepileptic drugs) given at constant doses throughout pregnancy and the puerperium. Phenobarbitone plasma concentrations were monitored in another 6 patients given phenobarbitone itself. A trend towards increasing primidone plasma concentrations during the second quarter of pregnancy was evident in all patients, with a concomitant significant decrease in primidone-derived phenobarbitone plasma concentrations. A trend towards a lowering of plasma concentrations of phenobarbitone administered as such was confirmed. These results suggest the usefulness of a careful monitoring of primidone and primadone-derived phenobarbitone during pregnancy and the puerperium. Discrepancies of findings with primidone and phenobarbitone are discussed in view of the possible mechanism involved.
D000293:Adolescent; D000328:Adult; D004827:Epilepsy / Q000188:drug therapy / Q000378:metabolism; D005260:Female; D006801:Humans; D010634:Phenobarbital / Q000097:blood / Q000378:metabolism*; D049590:Postpartum Period; D011247:Pregnancy; D011248:Pregnancy Complications / Q000188:drug therapy / Q000378:metabolism; D011324:Primidone / Q000097:blood / Q000378:metabolism*; D013997:Time Factors
D011324:Primidone; D010634:Phenobarbital