Evaluation of the Safety of Clozapine Use in Patients With Benign Neutropenia

Objective: To determine if clozapine can be safely utilized in psychiatric patients with benign neutropenia.

Methods: A single-center, retrospective chart review study of records from 2001 to 2014 was conducted in an inpatient psychiatric hospital. Patients included had benign neutropenia prior to receiving clozapine and received clozapine using modified monitoring guidelines. All available laboratory values for absolute neutrophil count (ANC) before initiation and during treatment were evaluated. The primary endpoint was difference in ANC after initiation of clozapine from before clozapine.

Results: A total of 26 patients were reviewed. The mean age at clozapine initiation was 34 years. The majority were African-American (73% [n = 19]), with more men than women (73% [n = 19] vs 27% [n = 7]). The mean lowest ANC value was not significantly different after clozapine initiation compared to before (1.5× 103 cells/mm3 and 1.4 × 103 cells/mm3, respectively; P = .22). The overall mean ANC was significantly higher after initiation than before (2.63 × 103 cells/mm3 and 2.13 × 103 cells/mm3, respectively; P < .001). There were no cases of severe neutropenia (ANC < 0.5 × 103 cells/mm3), and no patient was discontinued for falling below modified guideline limits. There were fewer occurrences of mild neutropenia (ANC < 2.0 × 103 cells/mm3) after clozapine initiation than before (16.0% and 31.4%, respectively; P < .001). There were also fewer occurrences of moderate neutropenia (ANC < 1.5 × 103 cells/mm3), with 2.1% after clozapine and 13.3% before (P < .001).

Conclusions: Twenty-six patients with benign neutropenia were safely treated with clozapine. Pre-clozapine neutropenia did not predict increased risk for severe neutropenia with clozapine. Patients had significantly fewer episodes of mild and moderate neutropenia after receiving clozapine compared to before.

J Clin Psychiatry 2016;77(11):e1454–e1459