COMBINATION VALPROATE CARBAMAZEPINE THERAPY IN PARTIAL EPILEPSIES RESISTANT TO CARBAMAZEPINE MONOTHERAPY

Eighteen patients with poorly controlled partial epilepsy on carbamaze pine monotherapy at maximum tolerated doses were treated with valproat e adjunctive therapy. Both medications were maintained for at least 3 months at the highest tolerated doses. Three patients had >50% decreas e in seizure frequency on bitherapy; six patients were moderately impr oved, with a 22-44% decrease in seizure frequency; the remaining nine patients were unchanged or worsened, with up to a 49% increase in seiz ure frequency. Five of six patients with more than four seizures per m onth improved on bitherapy. Four patients had a shift of predominant s eizure type from tonic-clonic to complex partial; two of these patient s were moderately improved and two had an overall increase in seizures . Clinical toxicity was common on bitherapy, managed by a reduction in carbamazepine dose in most patients. We conclude that valproate-carba mazepine bitherapy may be beneficial in approximately half of patients who have failed high-dose carbamazepine monotherapy; however, marked improvement is infrequent. Valproate-carbamazepine bitherapy is also f requently associated with clinical anticonvulsant toxicity at the begi nning of bitherapy, but this is generally easily managed with medicati on adjustment.