Effects of the Long-acting Calcium Channel Blockers, Amlodipine, Manidipine and Cilnidipine on Steroid Hormones and Insulin Resistance in Hypertensive Obese Patients

Abstract

To demonstrate that calcium channel blockers can improve insulin resistance clinically, we investigated the effects of the calcium channel blockers, amlodipine, manidipine and cilnidipine on serum levels of steroid hormones and insulin. Thirty hypertensive obese patients [15 men and 15 women; mean age 55.9 years, mean body mass index (BMI) 27.6] were divided into three groups and treated with either 5 mg of amlodipine, 20 mg of manidipine or 10 mg of cilnidipine. Blood pressure (BP), fasting plasma glucose (FPG), HbA1c, fasting serum immunoreactive insulin (F-IRI), insulin resistance index [as assessed by the homeostasis model assessment (HOMA-R)], serum DHEA, serum DHEA-S, plasma ACTH, serum cortisol, plasma renin activity (PRA), and serum aldosterone, were measured before and after 1, 2, 3 and 6 months of treatment. In all three groups, BP decreased significantly after 1 month and F-IRI and HOMA-R decreased significantly after 2-3 months. A concurrent rise in serum DHEA and DHEA-S levels was also observed, however, the differences were not significant. No changes in FPG, HbA1c, ACTH, cortisol, PRA or aldosterone levels were observed during treatment. We conclude that amlodipine, manidipine and cilnidipine all improve insulin resistance and consequently increase serum levels of DHEA and DHEA-S.