The Effect of Potassium Chloride and Spironolactone on Thiazide‐induced Potassium Depletion in Patients With Essential Hypertension

Total exchangeable potassium (K E ), red blood cell potassium (K RBC ), serum potassium (K S ) and blood pressure (BP) have been determined in 34 patients with essential hypertension after not less than 4 weeks' therapy with hydrochlorothiazide, 75 mg daily. K E was significantly lower than the levels found in untreated patients with essential hypertension, determined by the same method and in the same laboratory. K RBC and K S were also significantly lower than the values in normal individuals. The patients were then divided at random into two groups, one group receiving a potassium chloride supplement of 60 mEq/d., the other a spironolactone supplement of 100 mg/d. After 5 weeks of combined therapy the above parameters were again determined. Both groups presented a significant rise of K e , K rbc and K S . The rise of K S in the spironolactone group was significantly higher than that found in the potassium chloride group, but the increase of K E and K rbc in the two groups did not differ significantly. Spironolactone caused a significant reduction in systolic as well as diastolic BP, while potassium supplement did not influence the BP.