Zolpidem induced hyponatremia: a case report.

Zolpidem is a non-benzodiazepine hypnotic that acts by binding to (GABAA) receptor. This is a case report of a patient with chronic insomnia for which he had initially been receiving benzodiazepine hypnotic alprazolam and for the past three years, he had switched himself to non-benzodiazepine hypnotic, zolpidem and had progressively increased the dose to 20 mg. The patient presented with history of drowsiness, nausea and vomiting of short duration. Investigations revealed that the patient had hyponatremia. Decreased serum sodium, elevated urine sodium with normal urine osmolarity was detected. Therefore, we report this as a case of drug induced syndrome of inappropriate antidiuretic hormone (SIADH) as other likely causes were ruled out by appropriate investigations. The causality assessment was done according to the WHO scale and found to be "Probable".