A trial of the calcium antagonist felodipine in hypertensive type 2 diabetic patients

Although calcium antagonists may impair insulin release in vitro, clinical studies have produced conflicting results. Felodipine is a highly selective dihydropyridine calcium antagonist effective in the treatment of hypertension. The efficacy of felodipine was assessed in a double‐blind randomized placebo cross‐over study of 21 Type 2 diabetic patients with primary hypertension, 13 men and 8 women, with an age of 61 (range 46–73) years. Thirteen were controlled on oral hypoglycaemic therapy and 8 on diet alone. Mean (SD) blood pressure (mmHg) was 176(20)/102(8) after a 2–4 week placebo run‐in period, 169(21)/101(8) during the subsequent placebo period compared with 151(15)/88(9) after 4 weeks felodipine therapy (p< 0.001). Nineteen patients required 5 mg twice daily and 2 patients 10 mg twice daily to achieve a target diastolic pressure of 95 mmHg. Side‐effects seen with felodipine included ankle oedema, facial flushing, headache, and dizziness. During oral glucose tolerance tests performed after the felodipine and placebo phases, mean (SD) fasting blood glucose was 9.5(3.1) and 9.0(3.0) mmol I−1, respectively (NS), and the 90 min (peak) blood glucose was 19.1(4.8) and 18.1(4.8) mmol I−1, respectively (NS). Glycosylated haemoglobin and fructosamine concentrations likewise showed no significant changes. 1989 Diabetes UK