Recurrent fainting while seated solved: a rare case of olanzapine-induced non-orthostatic syncope in a young male

Olanzapine is an antipsychotic agent with alpha-1-adrenergic receptor blockade properties. While olanzapine therapy has been associated with orthostatic hypotension. symptomatic hypotension unrelated to increased postural stress has not been previously reported.

A 24-year-old male, newly initiated on the antipsychotic olanzapine, presented with new-onset multiple apparent near-syncope and syncope episodes often occurring while he was seated. Physical and neurologic exams were normal. complete bood count, basic metabolic panel, and urine drug testing were unremarkable. Baseline electroencephalogram (EEG) and head CT were normal. Echocardiogram revealed preserved biventricular function with left ventricular ejection fraction 60%–65%. Comprehensive autonomic testing, including multi-channel ECG recording, beat-to-beat blood pressure monitoring, and simultaneous EEG, documented multiple symptomatic paroxysmal hypotensive episodes occurring while the patient remained seated, without associated bradyarrhythmia or tachyarrhythmia. EEG slowing (delta waves) consistent with cerebral hypoperfusion accompanied the hypotensive episodes. In the absence of an alternative explanation, olanzapine was discontinued, and the symptoms resolved over the following weeks, supporting an olanzapine-induced aetiology.

The antipsychotic olanzapine may trigger hypotension without orthostatic stress or evident arrhythmia, suggesting an accentuated vasodepressor effect consistent with olanzapine’s known alpha-adrenergic blocker properties. Thus, olanzapine is a potential cause of intermittent, non-orthostatic hypotension; dose reduction or discontinuation should be considered in such cases.