Pleural effusion associated with clozapine treatment

Clozapine is an effective antipsychotic for treatment-resistant schizophrenia but is associated with a range of adverse effects. We present the case of a patient in her 60s with treatment-resistant schizophrenia who developed dose-dependent eosinophilia and bilateral pleural effusion shortly after clozapine initiation. Extensive diagnostic evaluation excluded infectious, cardiac and thromboembolic causes. Clozapine was discontinued and replaced with an alternative antipsychotic, resulting in complete clinical and radiological resolution of the pleural effusions, along with normalisation of eosinophil counts.

This case highlights a rare but clinically relevant probable clozapine-related adverse reaction and underscores the importance of considering somatic causes in patients with schizophrenia, where non-specific somatic symptoms may be misattributed to negative symptoms. Early recognition and prompt intervention are essential as discontinuation of clozapine may lead to full recovery.