Calcium antagonists for treatment of diabetes-associated hypertension. Metabolic and renal effects of amlodipine.

In hypertensive diabetics a strict blood pressure control may decrease the incidence of cardiovascular and diabetic complications. Long-term experience with the use of calcium antagonists is still limited. The metabolic and renal effects of long-term (8 months) therapy with amlodipine, 5 to 10 mg daily, were studied in 15 hypertensive patients with uncomplicated diabetes mellitus as compared with 15 patients with essential hypertension. After a 4 week placebo phase, the diabetics and essential hypertensive patients did not differ in mean blood pressure (156/93 +/- 16/7 v 150/95 +/- 9/5 mm Hg), body weight, creatinine clearance, microalbumin excretion, and C-peptide and lipid levels, while serum fructosamine was higher in the diabetics. In both groups, amlodipine caused a significant and long-lasting decrease of arterial pressure (8%), but did not modify creatinine clearance, microalbumin excretion, and serum lipid levels. In diabetics indices of diabetic control and the insulin and glucose response to an oral glucose tolerance test were unchanged, whereas in essential hypertension the insulin response to a glucose load was decreased (P = .033). Amlodipine exerts a comparable and long-lasting antihypertensive effect in hypertensive diabetics and patients with essential hypertension. Despite the significant decrease in arterial pressure, there was no change in urinary microalbumin excretion. Lipid metabolism, quality of diabetic control, and the insulin response to a glucose load were not affected unfavorably.