Effects of reduction in dose and discontinuation of hydrochlorothiazide in patients with controlled essential hypertension

M. S. Kochar, K. M. Landry and S. M. Ristow
Hypertension Section, Zablocki Veterans Affairs Medical Center, Milwaukee, WI 53295.

We studied the effects of a reduction in dose of hydrochlorothiazide from 50 to 25 mg/d, and its discontinuation for up to 22 months in 36 well-controlled hypertensive patients. Hydrochlorothiazide was discontinued if the diastolic blood pressure remained less than or equal to 94 mm Hg after a 6-month period on the lower dose of hydrochlorothiazide. No other changes were made in medications or diet. Sitting systolic blood pressure rose from 135 +/- 15 mm Hg to 140 +/- 14 mm Hg on reduction of the hydrochlorothiazide dose and rose still further to 145 +/- 20 mm Hg on discontinuation. Even greater increases in standing blood pressure were observed. There were no significant effects on the diastolic blood pressure with reduction of dose or discontinuation of hydrochlorothiazide. A significant decrease in the serum uric acid and a rise in serum potassium occurred. There were no changes in serum glucose or lipids on reduction in the dose of hydrochlorothiazide; whereas, with discontinuation, the serum lipids and hemoglobin A1C fell significantly. These results suggest that the benefits of a reduced dose of hydrochlorothiazide may not be as great as considered heretofore.