Both first-generation and second-generation antipsychotic medications can lower the seizure threshold, increasing the chances of seizure induction. This article reviews the published literature concerning the seizure-lowering effects of first- and second-generation antipsychotic medication. Unfortunately, rigorously controlled studies are relatively infrequent, and case reports form a large part of the available literature, limiting the confidence with which firm conclusions can be drawn. Of the first-generation antipsychotic medications, chlorpromazine appears to be associated with the greatest risk of seizure provocation, although other first-generation antipsychotics also lower seizure threshold. Conversely, molindone, haloperidol, fluphenazine, pimozide and trifluoperazine are associated with a lower risk of seizure induction. Clozapine is the second-generation antipsychotic most frequently associated with seizures, with risperidone appearing to confer a relatively low risk. Other factors such as history of seizure activity, concurrent use of other drugs that lower seizure threshold, rapid dose titration, slow drug metabolism, metabolic factors and drug-drug interactions appear to increase the chances of an antipsychotic medication inducing seizure activity.
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