The effects of verapamil, diltiazem, nifedipine and propranolol on metabolic control in hypertensives with non-insulin dependent diabetes mellitus.

The effects of one month's treatment with each of nifedipine, verapamil, diltiazem, propranolol and placebo, given in random order, on fasting plasma glucose, haemoglobin Alc, serum fructosamine, immunoreactive insulin, cholesterol, and triglyceride were studied in a group of 19 patients with hypertension and non-insulin dependent diabetes mellitus. The metabolic effects of the active drugs were generally small but fasting plasma glucose was increased by propranolol from 9.3 +/- 3.0 to 10.4 +/- 3.4 mmol/l (P less than 0.01) (mean +/- SD) and to 10.1 +/- 3.2 mmol/l (P less than 0.05) by nifedipine. Serum fructosamine was increased from 2.75 +/- 0.53 to 2.89 +/- 0.62 mmol/l (P less than 0.05) by diltiazem and to 2.91 +/- 0.65 (P less than 0.05) by propranolol. Verapamil increased fasting serum immunoreactive insulin: diltiazem and propranolol tended to reduce it. Propranolol but not the other drugs significantly increased serum triglyceride. Calcium antagonists may be preferable to beta adrenoceptor blockers for the treatment of hypertensive diabetics. Of the three calcium antagonists we studied, verapamil may have advantages over nifedipine and diltiazem.