Clozapine-Associated Leukopenia and Agranulocytosis in Western Cape, South Africa: A 3-Year Retrospective Cohort Study

Clozapine monitoring at a specialised psychiatric hospital: A retrospective chart review

Background

Clozapine is the only Food and Drug Administration (FDA) and National Institute for Care and Excellence (NICE) approved drug for treatment-resistant schizophrenia (TRS). Its potentially life-threatening haematological side effects of neutropaenia and agranulocytosis mandate rigorous monitoring of neutrophil counts, presenting unique, Third-World population challenges.

Aim

To describe the Clozapine white blood cell monitoring practice and outcomes in a local psychiatric hospital.

Setting

At a specialist Psychiatry unit in Durban, KwaZulu-Natal, which follows a modified algorithm of the South African Standard Treatment Guidelines for Clozapine monitoring.

Methods

A retrospective chart review composed of 120 patients on Clozapine treatment from 01 July 2018-31 December 2020. Demographic and clinical information was captured in a Redcap database. Descriptive statistics using categorical variables were used.

Results

The study population was from a low socioeconomic background, with low levels of education and employment. A baseline neutrophil count was recorded in 58 files (48.3%). Clozapine was stopped in 6 out of the 120 patients due to 'neutropaenia' (absolute neutrophil counts ranging from 1.18 to 1.6); none developed agranulocytosis. Their duration of Clozapine treatment ranged from 2 weeks-15 years.

Conclusion

Haematological monitoring frequency and documentation of patients receiving Clozapine were not in compliance with the hospital's adapted guidelines and may have resulted in the termination of treatment before true neutropaenia developed. Patients developed neutropaenia at low doses of Clozapine and after many years of treatment.

Contribution

These results suggest local Clozapine monitoring guidelines should be more strictly adhered to.