Antiepileptic drug withdrawal in patients with temporal lobe epilepsy undergoing presurgical video-EEG monitoring

Purpose: To investigate antiepileptic drug (AED) withdrawal during video-EE G monitoring in adult patients with temporal lobe epilepsy (TLE). Methods: Between 1995 and 1997, 102 consecutive patients with refractory TL E were admitted to the epilepsy monitoring unit for presurgical evaluation. Patients were monitored with ongoing AEDs being rapidly decreased and disc ontinued in 4-6 days. The monitoring was continued until sufficient numbers of seizures were recorded. Serum AED levels were checked at admission and after the first complex partial seizure (CPS). Results: In all, 89 patients had 429 CPSs (mean, 4.8 per patient), includin g 156 (36.4%) secondarily generalized. A mean of 153.8 h (16-451 h) was req uired for completing the monitoring in each patient. Forty-three (48.3%) pa tients experienced seizure clusters, and eight (9.0%) had generalized seizu res that had never occurred or had been absent for years. However, none evo lved to status epilepticus. Carbamazepine was the most commonly used AED in 71.9% of patients, followed by valproate and phenytoin. When the first CPS occurred, mean 77.2 h since the beginning of the monitoring, serum levels of these three AEDs were mostly subtherapeutic rather than minimal. Conclusions: Acute AED withdrawal effectively provoked seizures in TLE pati ents undergoing presurgical video-EEG monitoring. However. nearly 50% of pa tients had seizure clusters or secondarily generalized seizures. Serum AED levels were mostly subtherapeutic when the first CPS occurred.