What about platelet counts in clozapine users?

In this retrospective study, we aimed to evaluate platelet changes in patients taking clozapine for a variety of psychiatric disorders and hypothesized that there would be any changes in the course of the treatment.

Diagnoses were based on Diagnostic and Statistical Manual of Mental Disorders 4(th) edition. Forty-three patients, with the mean age of 36.23 ± 6.35 years were included into final analysis. Morning venous blood samples were used for platelet counts. Correlation analyses were performed between platelet counts and clozapine doses.

Paired t test did not reveal a significant change in platelet counts at the end visit compared to those of first assessment (p>0.05). Seven (17.9%) of 39 patients had platelet count below 180000 per cubic millimeter at least one time during their clozapine use. In five of these patients, the platelet count returned to a level above 180000 per cubic millimeter, without any dose change or other interventions. On the other hand, as for the issue of increased platelet count, results demonstrated that seven (17.9%) had platelet count above 400000 per cubic millimeter at least one time during clozapine use.

The present investigation revealed that platelet changes beyond WBC changes should be taken into consideration when using clozapine. Clinicians should be aware of the deviations from absolute threshold values.