Double-blind comparison of amlodipine and hydrochlorothiazide in patients with mild to moderate hypertension.

In the final analysis of this study at Week 26, 26% of the patients randomized to receive amlodipine attained blood pressure control with amlodipine alone compared with 33% of the patients allocated to hydrochlorothiazide (HCTZ). Neither amlodipine nor HCTZ produced clinically significant changes in pulse rate or in the electrocardiogram. Amlodipine treatment did not appear to produce clinically significant changes in blood lipids; HCTZ, however, produced an increase in total plasma cholesterol (delta 22.9 +/- 8.6 mg/dl). The incidence of side effects and the rate of patient withdrawal in the amlodipine and HCTZ groups were comparable. As expected, HCTZ therapy caused well-recognized biochemical alterations in cholesterol and potassium levels, whereas amlodipine was metabolically neutral.