Olanzapine-Induced Hyponatremia Secondary to syndrome of inappropriate antidiuretic hormone secretion (SIADH) : A Rare Antipsychotic-Related Adverse Drug Reaction

Saheena. C , Dr. Syed Mohammed Hussaini , Ayesha Siddiqa. M.K

Key words :- Olanzapine, Hyponatremia, Naranjo Adverse Drug Reaction Probability Scale, Pseudodementia, Syndrome of Inappropriate Antidiuretic Hormone Secretion

Olanzapine is a widely prescribed atypical antipsychotic with a generally favorable safety profile; however, rare but clinically significant electrolyte disturbances such as Hyponatremia have been reported. This case report describes olanzapine-associated hyponatremia secondary to Syndrome of Inappropriate Antidiuretic Hormone Secretion in an elderly patient. A 74-year-old female with a history of Pseudodementia presented with altered sensorium, irritability, sleep disturbances, and progressive cognitive decline. Laboratory investigations revealed severe hyponatremia with a serum sodium concentration of 117 mmol/L. A comprehensive clinical evaluation and detailed review of the patient’s medication history suggested a drug-induced etiology associated with prolonged olanzapine therapy. The suspected medication was promptly discontinued, and the patient was managed with hypertonic saline infusion, electrolyte supplementation, and supportive care. Subsequent monitoring demonstrated gradual correction of serum sodium levels to 139 mmol/L, accompanied by marked clinical improvement. Causality assessment using the Naranjo Adverse Drug Reaction Probability Scale yielded a score of 7 (probable adverse drug reaction), while evaluation with the WHO–UMC Causality Assessment System classified the reaction as “probable/likely.” This case highlights the importance of vigilant electrolyte monitoring in elderly patients receiving long-term antipsychotic therapy.

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"Olanzapine-Induced Hyponatremia Secondary to syndrome of inappropriate antidiuretic hormone secretion (SIADH) : A Rare Antipsychotic-Related Adverse Drug Reaction", IJSDR - International Journal of Scientific Development and Research (www.IJSDR.org), ISSN:2455-2631, Vol.11, Issue 3, page no.a418-a431, March-2026, Available :https://ijsdr.org/papers/IJSDR2603048.pdf

Volume 11 Issue 3, March-2026

Pages : a418-a431

Paper Reg. ID: IJSDR_307712

Published Paper Id: IJSDR2603048

Downloads: 000193

Research Area: Pharmacy All

Country: Ballari, Karnataka, India

Published Paper PDF: https://ijsdr.org/papers/IJSDR2603048

Published Paper URL: https://ijsdr.org/viewpaperforall?paper=IJSDR2603048

ISSN: 2455-2631 | IMPACT FACTOR: 9.15 Calculated By Google Scholar | ESTD YEAR: 2016

An International Scholarly Open Access Journal, Peer-Reviewed, Refereed Journal Impact Factor 9.15 Calculate by Google Scholar and Semantic Scholar | AI-Powered Research Tool, Multidisciplinary, Monthly, Multilanguage Journal Indexing in All Major Database & Metadata, Citation Generator

Publisher: IJSDR(IJ Publication) Janvi Wave

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