Is a different effect on sympathetic nerve activity between nisoldipine and cilnidipine in humans

The aim of this study was to investigate whether the different effect on sympathetic activity between nisoldipine, long-acting L-type calcium channel blocker, and cilnidipine, L- and N-type calcium channel blocker, using an identical group of healthy subjects. Eight healthy men (22 to 28 years) were given 10mg nisoldipine or 10mg cilnidipine in a randomized crossover design. In each trial, without medication on day 1 (control) and with medication on day 2, subjects were measured heart rate(HR), high frequency(HF)/low frequency(LF) of HR variability and plasma noradrenaline(NA) during head-up tilt test and palmer sweating during mental arithmetic test before and 1,2,4,6, and 8 h after administration time. Plasma concentration profiles were similar between both drugs. Two-occasional controls showed no significant difference in these parameters. Head-up tilt increased HR, LF/HF and plasma NA. There were no significant difference in HR and plasma NA in supine and head-up positions at any measured times between both drugs. LF/HF (3.3±1.1) in head-up position at 4 h during cilnidipine was significantly lower than that (6.2±1.6) during nisoldipine (p=0.012). None caused postural hypotension. While there was no difference in mental arithmetic induced sweating secretion between both drugs. Cilnidipine might have a weak inhibitory effect on reflex sympathetic activity induced by head-up tilt compared to nisoldipine. Clinical Pharmacology & Therapeutics (2004) 75, P6–P6; doi: 10.1016/j.clpt.2003.11.020