Abstracts

RATIONALE: Oxcarbazepine (OXC) is rapidly and almost completely metabolized to its active metabolite, 10-hydroxy-10,11-dihydro-carbamazepine (MHD) by a hepatic cytosolic arylketone reductase in humans. Carbamazepine has a similar structure but undergoes oxidation to form an epoxide metabolite that has been attributed to its adverse event profile including teratogenicity. OXC has been marketed in Argentina since 1990 for the treatment of newly diagnosed and poorly controlled patients with epilepsy. Since an epoxide metabolite is not present with OXC the pregnancy outcomes of patients taking OXC were reviewed.
METHODS: Our comprehensive epilepsy center has gathered information on 91 pregnancies through an Epilepsy Pregnancy Registry since 1995 for patients exposed to antiepileptic drugs (AEDs). Forty-two of these patients were on OXC during their pregnancies, 25 on monotherapy and 17 in combination with other AEDs.
RESULTS: No minor or major malformations were recorded in the OXC monotherapy group. Likewise, in a subgroup of pregnancies exposed to a combination of OXC and a benzodiazepine no malformations were noted. One cardiac malformation (ventricular septal defect) was recorded in a neonate exposed in utero to OXC/phenobarbital polytherapy, and another phenobarbital-related cardiac malformation was recorded in a case of phenobarbital monotherapy. No neural tube abnormalities were seen. All epileptic female patients of childbearing age were placed on folate supplement prophylaxis.
CONCLUSIONS: In our experience, OXC monotherapy was not associated with any fetal malformations. Although we have reviewed a large number of pregnancies, it is still insufficient to draw any definitive conclusions. We encourage all physicians to actively participate with their respective large-scale epilepsy pregnancy registries.
(Disclosure: Salary - Dr Carrazana is an employee of Novartis Pharmaceuticals., Honoraria - Dr Rabinowicz has received honoraria from Novartis Pharmaceuticals within the past 5 years.)