Potassium restoration in hypertensive patients made hypokalemic by hydrochlorothiazide.

Among 447 hypertensive patients, most with a history of diuretic-induced hypokalemia, 252 developed diuretic-induced hypokalemia while receiving hydrochlorothiazide, 50 mg/d. In a randomized study we evaluated the efficacy of three drug regimens in restoring potassium levels while maintaining blood pressure control: hydrochlorothiazide (50 mg/d) plus potassium supplement (20 mmol/d); hydrochlorothiazide (50 mg/d) plus potassium supplement (40 mmol/d); or hydrochlorothiazide (50 mg/d) with triamterene (75 mg/d) in one combination tablet. In all groups, mean serum levels of potassium rose within 1 week and showed no further change thereafter. However, the hydrochlorothiazide/triamterene and hydrochlorothiazide plus 40 mmol of potassium regimens were significantly more effective in restoring serum potassium levels than was the hydrochlorothiazide plus 20 mmol of potassium regimen. A significant increase in magnesium levels was observed only in the group treated with the hydrochlorothiazide/triamterene combination. Each regimen provided continued control of mild to moderate hypertension.