Comparison of sustained release verapamil and hydrochlorothiazide in hypertension--effect on blood pressure and metabolic variables.

The effect of once daily sustained release verapamil (200-400 mg/day) and low dose hydrochlorothiazide (25 mg/day) on blood pressure and metabolic parameters was compared in a cross-over study. The treatment periods lasted 6 months. The antihypertensive efficacy of verapamil was comparable to that of low dose hydrochlorothiazide. Plasma total cholesterol, LDL cholesterol, HDL cholesterol or triglycerides did not change significantly from the values at the end of the drug free run-in period either on verapamil or on hydrochlorothiazide. Statistically, serum insulin decreased significantly with verapamil (13.4 +/- 4.3 U/ml, m +/- SD) when compared with both the wash-out (16.2 +/- 5.7 U/ml) and hydrochlorothiazide (17.1 +/- 6.5 ml) periods. There were no significant differences in fasting blood glucose between the treatment periods. Serum uric acid concentration increased significantly (from 266 +/- 64 mumol/l) after the wash-out period (to 307 +/- 92 mumol/l) after hydrochlorothiazide, but did not change on verapamil (270 +/- 75 mumol/l). Serum potassium decreased significantly from 3.96 +/- 0.39 mmol/l after the wash-out period to 3.67 +/- 0.37 mmol/l on hydrochlorothiazide, but did not change on verapamil (3.94 +/- 0.28 mmol/l).