Effects of nitrendipine and other calcium antagonists on glucose metabolism in man.

Some calcium antagonists, including nitrendipine, were noted to cause a dose-dependent and reversible inhibition of insulin release in certain animal models. Therefore, it is important to know the effects of clinical treatment with calcium antagonists in nondiabetic or diabetic man. A review of the literature allows the following conclusions: Acute and short-term therapy with calcium antagonists in nondiabetic and diabetic individuals did not change glucose homeostasis assessed with or without a glucose load. Nevertheless, higher doses of calcium antagonists were occasionally noted to slightly impair glucose homeostasis in nondiabetics, whereas, in some studies of diabetics, a slight amelioration or deterioration of glucose tolerance was variably reported. In long-term studies, the longest extending over 5 years, no change in basal or in glucose-stimulated carbohydrate metabolism was apparent in nondiabetic or diabetic subjects. These results are corroborated by our placebo-controlled observations during antihypertensive monotherapy with nitrendipine in Type II diabetics. Thus, glucose and insulin profiles and areas under the curve, before and following standard breakfast, were not altered following nitrendipine treatment periods of 6 weeks and 6 months, respectively. Concomitant blood levels of HbA1 on nitrendipine also were not different from those on placebo. The available information indicates that calcium antagonists probably do not affect glucose homeostasis to a clinically relevant degree, although some minor influences especially of higher dosages cannot be excluded.