Antihypertensive effectiveness of amlodipine in combination with hydrochlorothiazide.

The antihypertensive and metabolic effects of amlodipine, a new calcium-channel blocker, in combination with hydrochlorothiazide (HCTZ) were compared with those of HCTZ in combination with placebo. After four weeks open treatment with HCTZ 50 mg/d, 20 patients were blindly allocated to receive placebo and 20 to receive amlodipine, if their diastolic arterial pressure supine and upright was 95 to 115 mm Hg. The patients were seen in the clinic every two weeks for 12 more weeks, where their arterial pressure (AP) and heart rate (HR) were measured supine and upright. Hydrochlorothiazide was kept at 50 mg/d, but amlodipine was increased from 2.5 to 5.0 to 10.0 mg/d as needed. At end of weeks 4 and 16 the AP and HR were measured hourly for 12 hours and 24 hours later. Serial clinical and laboratory evaluations including lipid profiles were done on all patients. Amlodipine treated patients had lower arterial pressures in both the supine and upright positions (P less than .001), higher HDL levels (P less than .05) and lower CHOL:HDL and LDL:HDL ratios (P less than .01), than placebo-treated patients. Also, amlodipine-treated patients had lower SGOT and SGPT levels (P less than .01) than placebo-treated patients. No changes in HR or weight were noted between the two groups of patients. Clinical side effects were few and mild and not different between the two groups. We conclude: (1) the addition of amlodipine to HCTZ enhanced its antihypertensive action; (2) amlodipine was safe and well tolerated; and (3) amlodipine, perhaps, has a favorable effect on lipids.