Clozapine-induced blood dyscrasias in Saudi Arab patients.

Background: Clozapine has shown superior efficacy over other antipsychotics. However, its use is complicated by the development of life-threatening hematologic adverse effects.

Objectives: This paper reports the incidence of clozapine-induced hematologic toxicity in Saudi Arab patients.

Setting: King Khalid University Hospital, Riyadh, Saudi Arabia.

Methods: Medical data of Saudi Arab hospitalized patients receiving clozapine was retrospectively reviewed during the period between August 2009 and August 2012. White blood cell (WBC) counts and differentials were recorded in a specific form to watch for any hematologic toxicity. The hematologic toxicities included in this report are: eosinophilia, thrombocytopenia, lymphocytopenia, and agranulocytosis/neutropenia/leukopenia combined.

Main Outcome Measure: Complete WBC count.

Results: During the study period 147 charts were reviewed. The mean age of patients was 38 ± 11.42 years and 52 % were males. During the study period 61 patients (42 %) developed 82 blood dyscrasias. Sixteen patients (10.9 %) developed agranulocytosis, neutropenia and leukopenia combined, while nineteen patients (12.9 %) developed lymphocytopenia, and seven patients (4.8 %) developed thrombocytopenia. Eosinophilia developed in 40 patients (27.2 %). During the first 18 weeks of therapy with clozapine, 21 (26 %) hematologic side effects were developed.

Conclusion: The data collected in this study does appear to indicate there may be an increased incidence of blood dyscrasias in Saudi Arabs which warrants further, more detailed, study. It would be of concern to psychiatric clinicians if the case of a genetic predisposition to clozapine-induced blood dyscrasias were proven in the future.