Increased seizures after discontinuing carbamazepine: results from the gabapentin monotherapy trial

Studies in patients with epilepsy undergoing telemetry evaluation for surgery have suggested that discontinuation of carbamazepine (CBZ) is associated with increased seizures. The period of observation in that setting, however, was limited to a few days. The authors reviewed the occurrence of seizures in patients with epilepsy who had all their antiepileptic medications discontinued during an 8-week period, converted to gabapentin monotherapy, and observed for 26 weeks as part of the gabapentin trial #945-082. Two hundred and seventy-five patients were enrolled. Kaplan-Meier estimates of time to exit for all patients showed that 18% of patients previously treated with CBZ completed the study as compared with 30% of the patients receiving other antiepileptic medications. Increase in the frequency of seizures was maximal in the 2 weeks following CBZ discontinuation. Seizures increased both in frequency and severity but no new seizure types were observed. The findings in this study show that removal of CBZ is associated with increased frequency of seizures in patients with a previous history of epilepsy with incompletely controlled seizures. The period of maximal increase was the first 2 weeks after CBZ discontinuation.