Amantadine-induced multiple spike waves on an electroencephalogram of a schizophrenic patient

Although amantadine is relatively free of side effects compared with levodopa, the incidence and severity of unwanted effects, such as hallucinations, insomnia and dizziness, markedly increase when the daily dose exceeds 200 mg. A 63-year-old schizophrenic female developed the Pisa syndrome following neuroleptic medication. She was started on a regimen of amantadine, 200 mg per day, on September 4, and the electroencephalogram (EEG) on September 11 was within normal limits. The dosage was increased to 300 mg on September 18 because there was no improvement and no side effects. Two days later a generalised convulsion occurred and an EEG revealed frequent multiple spikes or sharp waves with slow waves. No epileptic seizure has been observed since the amantadine was discontinued. The EEG on September 27 was again within normal limits. To our knowledge, the EEG of a patient with convulsion induced by amantadine has not been described previously. The epileptic mechanisms of amantadine have not been elucidated; however, it may be related to a modulating role of dopamine in the central nervous system.