January 14, 1983

Response of Thiazide-lnduced Hypokalemia to Amiloride

Author Affiliations

From the Clinical Pharmacology Section, Department of Medicine, University of Southern California School of Medicine (Drs Maronde, Milgrom, and Vlachakis), and the Los Angeles County/University of Southern California Medical Center (Dr Chan), Los Angeles.

JAMA. 1983;249(2):237-241. doi:10.1001/jama.1983.03330260055032

The effects of amiloride hydrochloride on thiazide-induced hypokalemia were evaluated. In metabolic balance studies, amiloride reversed thiazide-induced urinary potassium loss, restored plasma bicarbonate concentration and pH to pretreatment levels, and produced further increases in aldosterone secretion. Effects of long-term administration of hydrochlorothiazide and an amiloride-hydrochlorothiazide combination were compared in outpatients who had experienced thiazide-induced hypokalemia while receiving oral potassium supplements. After eight weeks, those given hydrochlorothiazide alone had an average serum potassium level of 3.01± 0.10 (SD) mEq/L, significantly lower than the control level (3.75 ±0.08 mEq/L). Those given the amiloride-hydrochlorothiazide combination had an average serum potassium level of 3.75 ±0.08 mEq/L, not significantly different from the control value (3.82 ±0.08 mEq/L). Both groups had increased plasma aldosterone concentrations and plasma renin activity. The potassium-conserving effect of amiloride persisted with extended therapy.

(JAMA 1983;249:237-241)