Clozapine and leukocytosis

Leukocytosis Associated with Clozapine Treatment: A Case Series and Systematic Review of the Literature

BACKGROUND AND OBJECTIVES

Clozapine is the only antipsychotic approved for treatment-resistant schizophrenia. Despite its superior efficacy profile as compared with other antipsychotics, clozapine remains underutilized. Clozapine monitoring systems clearly describe the proposed management of clozapine-induced neutropenia; however, no specific mention is made of how to interpret neutrophilic leukocytosis, despite that being a relatively frequent finding. Prescribers unfamiliar with this molecule may misjudge its clinical significance, potentially leading to untimely treatment interruption. Here, we systematically review the literature on the risk of neutrophilic leukocytosis during clozapine treatment, and describe eight additional cases among our patient cohort.

MATERIALS AND METHODS

We performed a systematic review of the literature on PubMed and Embase using the PRISMA 2020 guidelines, and selected all original reports describing either (1) the prevalence of neutrophilic leukocytosis during clozapine treatment, or (2) the clinical significance of neutrophilic leukocytosis. We described eight additional cases of neutrophilic leukocytosis during clozapine treatment while attending an outpatient psychiatric clinic.

RESULTS

Our research ultimately yielded the selection of 13 articles included in this systematic review. The case series highlighted the presence of stable and clinically unremarkable neutrophilia during a follow-up ranging from one to ten years.

CONCLUSIONS

Existing evidence indicates that leukocytosis associated with clozapine treatment can be considered as an asymptomatic and benign condition, suggesting that no change in clozapine treatment is needed upon its detection.

Clozapine versus other antipsychotics during the first 18 weeks of treatment: A retrospective study on risk factor increase of blood dyscrasias

Blood dyscrasias excluding agranulocytosis received limited attention in antipsychotic-treated patients during the first 18 weeks of therapy, although severe clinical conditions have been reported in a few cases. We extracted data records of 285 Caucasian patients after 18 weeks of antipsychotic treatments to investigate risk factors of blood dyscrasias. We observed a higher risk to develop both transient and persistent anemia, neutrophilia and eosinophilia in clozapine-treated patients, whereas in those treated with other atypical antipsychotics when compared to a reference group under typical antipsychotics, emerged an increased risk for transient neutrophilia and eosinophilia. Male patients revealed a higher risk of persistent eosinophilia, neutrophilia, and leukocytosis. Concomitant treatments with mood stabilizers or benzodiazepines proved to be risk factors for transient anemia, antidepressants for transient eosinophilia. Severe complications emerged in 3 cases of agranulocytosis. Cross-tabulation analysis showed a higher probability of a poor response in clozapine-treated patients with persistent anemia and a positive with persistent neutrophilia and eosinophilia. Our data evidenced that emerging blood dyscrasias were not associated with critical adverse effects, and only agranulocytosis required a treatment interruption. Other atypical antipsychotics might represent a viable alternative to potentially harmful clozapine and typical antipsychotics at the onset of life-threatening haematological alterations.

Leukocytosis after Clozapine Treatment in a Patient with Chronic Schizophrenia

Clozapine is an atypical antipsychotic drug that is approved by the US Food and Drug Administration (FDA) for the treatment of psychotic disorders. Agranulocytosis is a well-established side effect of clozapine; clozapine has also been associated with other blood dyscrasias like leukocytosis, albeit rarely. In this paper, we aim to report a case of possible clozapine-associated leukocytosis in a 41-year-old woman.

Leucocytosis in clozapine-treated patients as predictor of loss of treatment response?

Anecdotal evidence tends to suggest clozapine treatment as a cause of leucocytosis in schizophrenic patients, however, no conclusive evidence is available on this topic. We report the clinical cases of two schizophrenic men who were diagnosed with clozapine-related leucocytosis. The clozapine treatment was performed at a dose between 200 and 400 mg/day. When leucocytosis appeared, there was a loss of response to clozapine in both patients. Clozapine-induced leucocytosis in schizophrenic patients could be correlated to occurrence of psychotic symptomatology.