Effect of the antispasmodic trospium chloride on anorectal function

Aims: The parasympathetic innervated smooth muscle M. ani internus is one of the key players of continence and defecation. An increased pressure in the lower anal channel by atropin has recently been reported [Aliment Pharmacol Ther 1998; 12: 747–754]. Trospium chloride, a atropin-like peripheral parasympatholytic antispasmodic, has been shown to exert multiple effects on the GI-tract such as delayed gastric emptying, prolonged oro-coecal time and reduction of phase III of small bowel motility [European Journal of Clinical Pharmacology 1993; 44: 219–223; Gut 1994; 35: 27–33]. The aim of the present study was to investigate the effect of trospium chloride on the anorectal function.

Methods: Anorectal manometry was performed of 12 healthy volunteers (6 females, 6 males; aged 29 (19–39) years) after application of 2mg trospium chloride or placebo i.v. in a double-blind, placebo-controlled, cross-over study with a wash-out period of 28 days. After preparation with a microclist anorectal manometry was performed without medication and repeated 5 minutes after intravenous injection of verum or placebo. The evaluated parameters were the mean resting pressure (MRP), mean squeeze pressure (MSP), balloon volume at first (BVF) and urge sensation (BVU). Data given as mean±SEM.

Results: The difference of mean resting pressure before (MRP pre 73,6±4,6mm Hg) and after (MRP post 80,8±4,2mm Hg) trospium chloride application was 7,2±3,6mm Hg and did statisticaly not differ from that obtained with placebo 5,3±4,2mm Hg (MRP pre 62,7±4,8mm Hg; MRP post 68,1±4,4mm Hg). Similarly mean squeeze pressure (MSP), balloon volume at first (BVF) and urge sensation (BVU) showed no significant difference after application of Trospiumchlorid or placebo.

Conclusion: Trospium chloride has no effect on the muscle tone of M. sphincter ani internus represented by the mean resting pressure. Furthermore, it does neither influence other parameters of anorectal function such as mean squeeze pressure, balloon volume at first and urge sensation.