Urinary antispasmodics are the name given to a group of medicines that block the effects of acetylcholine and inhibit involuntary detrusor muscle contractions. The detrusor muscle is found in the wall of the bladder. Urinary antispasmodics are used to treat symptoms of urge incontinence and overactive bladder.
Acetylcholine is the main neurotransmitter of the parasympathetic nervous system (also called the cholinergic system). The parasympathetic nervous system regulates various organ and gland functions at rest, including digestion, defecation, lacrimation, salivation, and urination.
Acetylcholine acts on two types of receptors; nicotinic and muscarinic cholinergic receptors. Some urinary antispasmodics are non-selective, which means they bind to both nicotinic and muscarinic receptors. Others selectively block M3 (a specific type of muscarinic receptor). Selective antispasmodics cause less drowsiness than non-selective antispasmodics but may cause more constipation, dry mouth, and blurred vision.
