Nonsteroidal anti-inflammatory drug-induced severe hyponatremia.

Hyponatremia (serum sodium level, <135 mmol/L) occasionally may develop in the course of treatment with nonsteroidal anti-inflammatory drugs, which are usually used in daily clinical practice. Nonsteroidal anti-inflammatory drugs diminish the normal inhibitory effect of prostaglandins on the activity of antidiuretic hormone and can therefore reduce free water excretion, leading to water retention and induction or exacerbation of hyponatremia. In this report, we present a case of hyponatremia in a 78-year-old man who had received meloxicam, a nonsteroidal anti-inflammatory drug.