Calcium channel blocker drugs and diabetic control

Calcium channel blockers are now widely used and there have been case reports of hyperglycemia with nifedipine. In a double-blind, randomized, crossover study of the effects of 4 weeks of therapy, each with two dihydropyridine calcium channel blocker drugs, nifedipine and nicardipine, glucose tolerance, plasma insulin levels, and hemoglobin A1 were assessed in 20 patients with non-insulin-dependent diabetes (mean age 59 years). There was no significant difference in glucose tolerance on active therapy (AUC: control, 548.3 +/- 24.8; nifedipine, 559.3 +/- 41.0; and nicardipine, 589.3 +/- 40.3). Similarly, despite producing significant hemodynamic effects, these drugs produced no significant effect on plasma insulin and hemoglobin A1 levels. Calcium channel blocker drugs may be useful alternatives to thiazide diuretics and beta-blockers in the treatment of ischemic heart disease and hypertension, especially in patients with diabetes.