Long-term effect of clozapine in schizophrenia a retrospective study of 108 chronic schizophrenics treated with clozapine for up to 7 years

Abstract

In Finland, clozapine use has been increasing during the last few years after the catastrophic accumulation of haematological side-effects. These had resulted in strict restrictions on the use of clozapine, and special permission had to be obtained for the treatment of severely drug-resistent schizophrenic in-patients. In this retrospective, long-term study, the clinical effects and untoward effects of clozapine were evaluated under these special circumstances. We interviewed 108 chronic schizophrenic patients, with a duration of illness from 2 to 43 years (mean 15 years), most of them resistant to previously used neuroleptics. Complementary information was obtained from personnel and medical records. Average daily clozapine dosage was 360 mg (total 235 g) for 1,5 years (range 1 month - 7 years). Of these chronic patients, every fifth patient (23%) was able to leave the hospital with clozapine medication. In every third patient, a distinct effect in chronic symptoms, hallucinations. delusions, and psychomotor hyperactivities, could be registered. In 13%, medication had been discontinued because of lack of efficacy or because of side effects. There were mild untoward effects in 41% of patients, 5 patients had severe side effects, one had reversible leucopenia, severe tachycardia, severe sedation and hypersalivation and two had severe extrapyramidal symptoms (possibly before clozapine). Thus severe side-effects were rare, except for the one case of leucopenia. In contrary to other countries, the incidence of haematological side-effects seems to remain high in Finland, being roughly 1%. This clearly limits clozapine use, and requires regular controlling of patients.