Bethkast 25 Tablets BETHKAST contains Bethanechol Chloride, a synthetic ester that acts as a selective muscarinic cholinergic receptor agonist. It selectively stimulates postganglionic parasympathetic muscarinic receptors, particularly in the urinary bladder and gastrointestinal tract, with minimal or no effect on nicotinic receptors. In the urinary bladder, bethanechol increases detrusor muscle tone, stimulating contraction to produce a micturition reflex and initiate voiding, while simultaneously relaxing the internal sphincter. It also enhances gastric motility and tone. BETHKAST is indicated for the treatment of acute postoperative and postpartum non-obstructive urinary retention, and neurogenic atony of the urinary bladder with retention.