Summary

Objectives: The aim of this study was to compare the effects of amlodipine and propranolol on insulin sensitivity in obese patients with essential hypertension. Twenty-four hypertensive non-glucose intolerant patients with android obesity and body mass index 25-35 kg/m2, with diastolic blood pressure > 95 mmHg and < 115 mmHg, were studied after eight weeks of antihypertensive medication.

Patients and methods: The patients were divided into two groups of 12 patients each, and after a four-week period of placebo received amlodipine (5-10 mg/daily) or propranolol (160-320 mg/daily). An insulin sensitivity IS test (insulin suppression test) was performed after the placebo period and after 20 weeks of treatment. The levels of serum creatinine, electrolytes and uric acid, and the lipid profile were determined.

Results: Similar reductions in blood pressure were observed in both groups. Before active therapy, the IS rate did not differ between the groups. Propranolol therapy induced a significant reduction in IS (0.34 ± 0.16 vs 0.23 ± 0.09; p = 0.038), while no change in IS was observed in the amlodipine-treated group (0.33 ± 0.29 vs 0.30 ± 0.18; p> 0.05). No changes were observed in the remaining laboratory parameters evaluated, although the amlodipine-treated group showed higher levels of high-density lipoprotein cholesterol (45 ± 13 mg/dl vs 35 ± 9 mg/dl; p = 0.03) and a tendency to lower levels of triglycerides (124 ± 61 mg/dl vs 189 ± 99 mg/dl; p = 0.07) at the end of the study compared with the propranolol-treated group.

Conclusions: The results suggest that propranolol therapy in obese patients with essential hypertension resulted in an impairment in insulin sensitivity whereas amlodipine therapy showed no deleterious influence on IS. As insulin resistance and consequent hyperinsulinemia are risk factors for coronary heart disease, the use of a drug such as amlodipine may be a useful option in the treatment of obese patients with hypertension.