Calcium entry blockers and their effects on glucose metabolism.

Calcium entry blockers have been used for cardiovascular disturbances such as angina pectoris and hypertension. Calcium is, however, involved in the release of several hormones. The process of insulin secretion by the pancreatic beta-cells is dependent on calcium. Thus, calcium-entry blockers may interfere with insulin secretion. This effect has been confirmed in vitro in isolated islets as well as in animal studies. A few case reports describe the deterioration of glycaemic control or development of frank diabetes mellitus during treatment with nifedipine or diltiazem. In general, however, there are no important negative effects of calcium-entry blockers on glucose tolerance, either in non-diabetic persons with hypertension, or in patients with diabetes mellitus. Hence, these drugs appear to be a good choice for use in diabetic patients with cardiovascular diseases.