Clozapine-induced seizures: recognition and treatment.
OBJECTIVE
To inform clinicians about the types of seizures that can be induced by clozapine and to provide recommendations for treatment.


METHODS
We identified articles on clozapine-induced seizures from a MEDLINE search of the English-language literature from 1978 to July 2006. The frequency of each type of seizure and the dosages of clozapine associated with seizures were compiled. In addition to this review, we report a new case illustrating the challenge of diagnosing subtle seizure activity.


RESULTS
The tonic-clonic variety is the most frequently described clozapine-induced seizure. Myoclonic and atonic seizures together constitute about one-quarter of the reported seizures. The mean dosage of clozapine associated with seizures is not high (less than 600 mg daily).


CONCLUSIONS
It may be difficult for clinicians to recognize subtle types of clozapine-induced seizures, such as myoclonic, atonic, or partial seizures. Clinicians should not place excessive reliance on the plasma level of clozapine or electroencephalogram findings to predict the occurrence of seizures. When a first seizure occurs, it is recommended that the dosage of clozapine be reduced or an alternative antipsychotic agent be employed. If a second seizure occurs, an anticonvulsant drug should be started. Special attention should be paid when commencing or discontinuing concurrent medication that may affect the plasma level of clozapine.
Wong
Jason
J
Providence Continuing Care Centre Mental Health Services, Kingston, Ontario, Canada.
Delva
Nicholas
N
D014150:Antipsychotic Agents / Q000009:adverse effects* / Q000097:blood; D001921:Brain / Q000503:physiopathology; D003024:Clozapine / Q000009:adverse effects* / Q000097:blood; D004334:Drug Administration Schedule; D004569:Electroencephalography; D004830:Epilepsy, Tonic-Clonic / Q000139:chemically induced* / Q000175:diagnosis / Q000628:therapy; D005260:Female; D006801:Humans; D008875:Middle Aged; D012563:Schizophrenia, Paranoid / Q000188:drug therapy*; D012720:Severity of Illness Index
D014150:Antipsychotic Agents; D003024:Clozapine