Patterns of seizure activation after withdrawal of antiepileptic medication.

Effects of withdrawal of anticonvulsant drugs on the temporal profile of occurrence and the type of seizures were investigated in 40 intractable epileptic patients who were candidates for surgical treatment. EEG and behavior were monitored while drugs were reduced to allow localization of the epileptogenic region. The rapid withdrawal of drugs caused a rebound effect, triggering either generalized seizures during a brief period or a longer-lasting increase in partial seizures. These increases in seizure frequency appeared related to change in dosage rather than to dosage itself, since they remained largely confined to the early period following reduction of an anticonvulsant.