Olanzapine-induced ankle edema: A case report on a rare adverse effect

Olanzapine, a second-generation antipsychotic, is widely used for the treatment of schizophrenia and mood disorders but is associated with various side effects, including rare cases of peripheral edema. We report a case of a 48-year-old female with bipolar II disorder who developed bilateral pitting ankle edema 10 days after initiating olanzapine therapy. Clinical examination and investigations ruled out cardiac, renal, hepatic, and endocrine causes. The edema resolved completely within two weeks of discontinuing olanzapine and switching to amisulpride. Although peripheral edema is an uncommon adverse effect, it may mimic serious medical conditions, leading to unnecessary investigations. Several mechanisms have been proposed, including α1-adrenergic and 5-HT2 receptor blockade, contributing to vasodilation and fluid retention. This case highlights the need for clinicians to be aware of this potential reaction, allowing for timely identification and appropriate management. Reporting such cases contributes to post-marketing surveillance and supports safer, more informed use of antipsychotic medications like olanzapine.