ASSESSMENT OF THE ANTICHOLINERGIC EFFECT OF THE NEW ANTIHISTAMINE MIZOLASTINE IN HEALTHY-SUBJECTS

1 Twelve healthy subjects were enrolled in a double-blind placebo controlled cross-over study in order to assess the possible anticholinergic effects of four doses of a new antihistamine compound, mizolastine, compared with hyoscine butylbromide (HBB) used as a reference anticholinergic drug. 2 Although mizolastine, a potent and selective H-1-receptor blocker has no affinity for muscarinic receptors and does not antagonize the effects of carbachol in rodents, a study was initiated to investigate its effects on various effectors possessing muscarinic receptors (eye, heart, sweat gland, salivary gland). 3 HBB (40 mg, s.c.) impaired accommodation, decreased salivary flow and inhibited cardiac sinus arrhythmia. Pupil diameter and maximum constriction speed, carbachol-induced skin sweating and Valsalva ratio were unaffected. 4 Mizolastine (5, 10, 20, 40 mg p.o.) did not affect any parameter at any time point, demonstrating a lack of anticholinergic effect.