Four Cases of Seizures Induced by Low Doses of Clozapine in Schizophrenic Patients

Yoon, Jun Hyun; Kim, Jung Jin; Paik, In Ho

Abstract

Clozapine is an atypical antipsychotics that has been shown to be effective in treating patients with refractory schizophrenia and those with intolerance to currently available antipsychotics. It also appears to be less likely to cause extrapyramidal symptoms and tardive dyskinesia. But clozapine has been associated with an unusual high incidence of seizures in patients with no previous history of ictal episodes. Seizures occur in approximately 1% of patients treated with antipsychotic drugs. But the prevalence is higher with clozapine. Clozapine-induced seizures are reported to occur in a dose-related manner by progressively lowering the seizure threshold on most all patients as the dose is increased. But seizure does not usually necessitate discontinuation of clozapine treatment. We experienced four cases of seizure induced by low doses of clozapine treatment in schizophrenic patients. Since most of the seizures have occurred soon after increase of a clozapine dose, they may have been related more to rapid increase in blood clozapine levels than to that of dose. It is also possible that dose did not accurately predict blood levels for these patients. The possibility of seizures should not pose a barrier to clozapine treatment for patients with refractory psychotic disorders. The risks and morbidity of seizures can be minimized through attention to clinical management.