The effect of ciclotropium on human heart rate

Ciclotropium is a recently developed parasympathicolytic agent. Plasma concentration and heart rate increase (the most prominent anticholinergic effects) were measured in 12 healthy subjects before, during and after a 15-min intravenous infusion of 10 mg ciclotropium. The effect was described by using either a linear or a nonlinear (Emax) effect model linked to a linear three-compartment kinetic model via an effect compartment. Maximum heart rate increase was 33 (10) beats.min-1, and half-value duration of effect was 41 (9) min. Total plasma clearance was 0.51 (0.13) l.min-1, and mean terminal elimination half-life was 12(4) h, whereas the equilibration half-lives of drug removal from the effect compartment ranged from 2 to 14 min.