Side effects of clozapine

Publisher Website
Google Scholar
Abstract
In addition to the low risk of agranulocytosis, several more frequent side effects are associated with clozapine therapy. We tried to estimate the incidence of these side effects. We analysed 391 treatments in 315 inptients, who received clozapine alone or combined with other neuroleptic and antidepressant drugs. Two thirds were combined treatments, one third were treatments with clozapine alone (i.e., no other neuroleptic, antidepressant or anticonvulsive drugs were allowed). The numbers in brackets show the incidence based on the analysis of the treatments with clozapine alone. In 49% (61%) of the treatments a rise in the liver enzyme values was observed. However, counting only the cases in which a two-fold increase over the normal values was observed, the incidence was reduced to 20% (31%). Increase in temperature was observed in 4% (6%) and leukopenia (leukocyte count under 3500/μl) was recorded in 2% (2%). Hypotensive dysregulation (systolic blood pressure under 90 mm Hg) was observed in 25% of all treatments and pharmacogenic delirium in 8%. No cases of agranulocytosis were observed. Mean treatment duration was 56 days, mean daily dosage 257 mg. The mean age of the patients was 34 years. In the overall evaluation 71% of the treatments were classified as successful; clozapine therapy was continued after discharge in 68% of the treatments. Adverse reactions (delirium, rise in temperature, hypotension, fatigue, rise in liver enzymes) necessitated a change of medication in 17% of the treatments. Change-over to another neuroleptic drug due to ineffectiveness of clozapine was necessary in 7% of the treatments. The quality of the data is somewhat adversely influenced by the fact that the study was conducted retrospectively on the basis of medical records.