Combination Therapy of Angiotensin II Receptor Blocker and Thiazide Produces Severe Hyponatremia in Elderly Hypertensive Subjects

Abstract

Thiazide diuretics are known to produce severe hyponatremia as well as hypokalemia. The present study demonstrated severe hyponatremia in three hypertensive patients who had received combination therapy consisting of an angiotensin II receptor blocker (ARB) and thiazide. The serum sodium (Na) levels in all three cases were markedly reduced to below 116 mmol/L, and the patients exhibited augmented urinary excretion of Na with a reduced circulatory blood volume. After withdrawing the ARB and thiazide treatment, the serum Na levels normalized within one to two weeks. Combination therapy with ARBs and thiazide may cause hyponatremia in elderly patients.