Plasma Glutathione Concentrations Are Associated with Leukocyte and Neutrophils’ Counts in Clozapine-Treated Patients

Clozapine’s potential hematological toxicity, particularly its effect on white blood cell counts, is well documented and routinely monitored in clinical practice. In this study, a significant association was identified between reduced glutathione levels and neutrophil counts in patients undergoing clozapine treatment. Among the variables analyzed, glutathione concentration showed the strongest correlation with neutrophil levels, suggesting a potential role for antioxidant status in mediating clozapine’s hematological effects. Objective: The study aimed to evaluate the relationship between plasma concentrations of clozapine, its active metabolite N-desmethylclozapine, reduced glutathione, and treatment duration, in relation to total leukocyte and neutrophil counts in patients attending an outpatient psychiatric clinic. Methods: Plasma levels of clozapine, N-desmethylclozapine, and reduced glutathione were quantified using validated analytical techniques. Complete blood counts were obtained, and a multiple regression analysis was conducted to identify factors most strongly associated with variations in neutrophil count. Results: Reduced glutathione levels were significantly associated with neutrophil counts (p = 0.009), representing the most robust association among the variables examined. Clozapine concentration and duration of treatment were also found to be relevant contributors to changes in hematological parameters. Conclusions: These findings suggest that individual antioxidant capacity, particularly involving glutathione metabolism, may influence susceptibility to clozapine-related neutropenia. This insight could inform future strategies for monitoring and managing clozapine-treated patients, potentially aiding in the identification of those at increased risk for hematological side effects.