Cimetropium Bromide (DA-3177) is a mAChR antagonist for long-term treatment of irritable bowel syndrome.

Cimetropium Bromide behaves as a competitive antagonist of muscarinic-mediated contractions in isolated colonic preparations from both species, with affinity values (pA2) ranging between 7.41 and 7.82[1]. Cimetropium has potent antimuscarinic effect in inhibition of contraction of longitudinal muscle preparations. In the superfusion experiments of the preparation which has been preloaded with labelled choline, Cimetropium decreases the labelled ACh release induced by electrical field stimulation under the muscarinic autoinhibition blocked-condition[2].

When administered intravenously to conscious dogs provided with a colonic Thiry fistula, Cimetropium is a potent inhibitor of large bowel motility evoked by both exogenous and endogenous stimuli. Cimetropium Bromide (10-100 μg/kg) counteracts colonic motor response to neostigmine administration with an ID50 of 27.9 μg/kg; both tonic and phasic components of contractile response are affected. In a comparable range of doses (3-100μg/kg), the drug inhibits motor activity elicited by intraluminal distension[1].

[1]. Identification of orally administered cimetropium bromide in the colon of the rat and its possible local spasmolytic effect. [2]. Saitoh N, et al. Characterization of antimuscarinic effect of cimetropium bromide in guinea pig ileum. J Smooth Muscle Res. 1997 Feb;33(1):1-9.