Continuation of Treatment With Clozapine After an Episode of Neutropenia.

BACKGROUND

Clozapine is the most effective in treatment-resistant schizophrenia. Neutropenia is an adverse effect of the drug requiring treatment discontinuation. This study related treatment continuation with little or no interruption after a neutropenia episode. The study contrasted from rechallenge studies after an extended treatment interruption.

METHODS

This retrospective chart audit examined 37 patients with an episode of neutropenia. It described characteristics of patients continuing treatment with minimal interruption.

FINDINGS: Thirty-one patients continued treatment after an initial treatment interruption for less than 3 days. A probable cause for neutropenia other than clozapine was identified in 14 patients. Twelve patients continued treatment with a change in the absolute neutrophil counts threshold to 1000/μL to determine treatment cessation. Most patients recovered from the index episode of neutropenia within 2 days. They also frequently presented with recurring benign episodes of low neutrophil cell counts during treatment than a comparative group.

IMPLICATIONS: The study recommends modifying clozapine treatment protocol absolute neutrophil count thresholds to less than 1000/μL to determine treatment cessation. Consideration of other probable causes for neutropenia, diurnal variations in cell counts, and laboratory errors reduced preemptive discontinuation of treatment. A risk-benefit approach supports continuing clozapine treatment after an episode of neutropenia.