Increase in white cell and neutrophil counts during the first eighteen weeks of treatment with clozapine in patients admitted to a long-term psychiatric care inpatient unit.

Abstract Introduction Clozapine is an antipsychotic drug that has shown to be more effective than other antipsychotics in the treatment of schizophrenia, but its use is limited due to its side effects, particularly by the risk of causing agranulocytosis. A study was made on the variations in white cell and neutrophil counts in patients treated with Clozapine in a Long-term Psychiatric Unit. Methods A retrospective observational study was conducted with a sample of women of our long-term psychiatric care unit who had been treated with Clozapine. A study was made on the variations in white cell and neutrophil counts during the first 18 weeks of treatment, as well as the onset of leukopenia, neutropenia, agranulocytosis, and the influence of concomitant drugs. Results and conclusions The study included 55 patients on treatment with Clozapine. The incidence rate of neutropenia was 1.82% (95% CI: 0.05–10.13). The incidence rate of leukopenia and agranulocytosis was 0%. An increase in white cell and neutrophil counts from baseline to week 3–4 was observed. Only small variations were observed after this time, but the counts remained higher than the initial values. These changes were statistically significant in the white cell count: One-way repeated ANOVA with Greenhouse–Geisser correction F (11.47, 37) = 2.114 ( P  = .011); and in neutrophils: One-way repeated ANOVA with Greenhouse–Geisser correction F (10.3, 37) = 3.312 ( P  = .0002), and MANOVA F (18, 37) = 2.693 ( P  = .005), η P 2 = 0.567 . The influence of concomitant drugs (lithium, valproic and biperiden) was not significant on the overall increase found in white cells or neutrophils (MANOVA).