Tiotropium Bromide (BA679 BR) is a muscarinic acetylcholine receptor (mAChR) antagonist that blocks the binding of the acetylcholine ligand and subsequent opening of the ligand-gated ion channel. IC50 & Target: mAChR In Vitro: Tiotropium Bromide stops signaling between neurons and leads to muscle relaxation. Tiotropium Bromide is a long-acting, 24 hour, anticholinergic bronchodilator used in the management of chronic obstructive pulmonary disease. Tiotropium Bromide improves symptoms of chronic obstructive pulmonary disease complicated by chronic heart failure.