Clinical and electrographic effects of acute anticonvulsant withdrawal in epileptic patients. We retrospectively investigated the effects of acute antiepileptic drug (AED) withdrawal on seizure symptomatology--including frequency, clinical features, and electrical onset--by studying 35 patients during evaluation for epilepsy surgery. The highest risk for both partial and secondary generalized seizures occurred during absent or subtherapeutic, and not during rapidly falling, AED levels. AED withdrawal had minimal effect on clinical symptomatology or electrographic onset. 