Acute Asymptomatic Pericarditis Following Olanzapine Overdose

Olanzapine, a widely utilized atypical antipsychotic, has demonstrated substantial efficacy in managing schizophrenia and bipolar disorder, making it a cornerstone in the treatment of these conditions. Despite its therapeutic benefits, its use has been increasingly associated with adverse cardiovascular outcomes, necessitating a thorough understanding of these risks. Olanzapine is notably associated with metabolic side effects, including significant weight gain, hyperlipidemia, and hyperglycemia, which collectively predispose patients to cardiovascular disease. A rare but important adverse reaction to olanzapine overdose is acute pericarditis. While pericardial effusion with peripheral edema has been described, cases of acute pericarditis as an early manifestation remain exceedingly rare, and the underlying mechanism is poorly understood. We present the case of a male patient in his mid-30s with schizoaffective disorder who intentionally ingested approximately 300 mg of olanzapine in a suicide attempt. On presentation, he was somnolent but hemodynamically stable. Electrocardiography revealed diffuse ST-segment elevations and PR depressions consistent with acute pericarditis, despite the absence of chest pain or dyspnea. Cardiac biomarkers were normal. The patient was treated conservatively with aspirin and colchicine, with subsequent resolution of electrocardiographic changes by hospital day three. Clinicians should be vigilant for signs of acute pericarditis following olanzapine overdose, even in asymptomatic patients, as early electrocardiographic changes may be the only clue. Prompt recognition and management are crucial because untreated pericarditis can progress to complications such as cardiac tamponade or pericardial effusion, which carry a rare but real risk of cardiac arrest. This case highlights an uncommon but clinically relevant cardiovascular complication of olanzapine overdose and underscores the importance of routine cardiac monitoring in such scenarios.