A study, published in Hypertension Research, evaluated the effect of cilnidipine on insulin sensitivity. Cilnidipine was administered to ten patients with essential hypertension for 12 weeks at 5 to 10 mg/day. Mean age and body mass index (BMI) were 57.7 +/- 5.0 (SEM) years old and 27.1 +/- 1.5, respectively. BP, serum levels of catecholamines, glucose and lipid were assessed before and after treatment. Insulin sensitivity was measured using a euglycemic hyperinsulinemic clamp method using an artificial pancreas before and after treatment. Cilnidipine significantly decreased BP from 154/96 to 137/84 mmHg. Glucose infusion rate was also significantly increased by 20.8%, from 3.27 +/- 0.36 to 3.95 +/- 0.55 mg/kg/min. HbA1C and serum lipid levels (total cholesterol and triglyceride) were not affected. Cilnidipine did not cause any significant increase in serum norepinephrine levels (278 +/- 25.2 vs. 332 +/- 33.6 pg/ml). The results thus suggested that cilnidipine improved insulin sensitivity, possibly due to its vasodilatory action without stimulating sympathetic nervous activity.