Hassam Ali MD1*, Washma Amir MD2 and Shiza Sarfraz MD3

Hyponatremia is a conceivably fatal complication of thiazide diuretics. A loop diuretic, as compared to thiazides, is much less likely to cause symptomatic hyponatremia. We report an unusual case of refractory hyponatremia of 109 meq/L (Normal range (NR): 136-145 meq/L) in a 57-year-old female within two weeks of increasing dose of metolazone, a thiazide-like diuretic. After treatment with intravenous 3% hypertonic saline infusion, fluid restriction and discontinuation of metolazone, and ruling out other possible causes of hyponatremia, the serum sodium levels failed to improve adequately until Tolvaptan was added for a short duration. Our report aims to highlight the life-threatening dilemmas associated with thiazide diuretics and to manage it by careful correction and monitoring of sodium levels with the possible use of vaptans for refractory cases.

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