Abstract
Clozapine toxicity is a potentially life-threatening condition that can result from altered drug metabolism, leading to elevated serum levels and systemic adverse effects. Although it is commonly associated with infections and metabolic changes, its occurrence in the setting of recent cardiac surgery and pleural effusion is not well documented. We present the case of a 42-year-old female with a history of schizoaffective disorder, bipolar disorder, and recent mechanical aortic valve replacement, who developed worsening dyspnea and postoperative pleural effusions. Her hospital course was complicated by supratherapeutic clozapine levels, recurrent pleural effusions requiring thoracentesis and chest tube placement, and anticoagulation management challenges due to the mechanical valve. Despite diuresis and pleural drainage, her symptoms persisted, leading to clozapine discontinuation. After dose adjustments and close monitoring, her respiratory status improved, and serum clozapine levels returned to normal.