antispasmodics

Antispasmodics are medications that reduce or relieve smooth muscle spasms in various organs. They are commonly used to treat functional disorders marked by cramps or excessive muscle contractions, especially irritable bowel syndrome (IBS) and urinary tract symptoms. These drugs work through different mechanisms, including anticholinergic effects that block acetylcholine at muscarinic receptors to decrease involuntary contractions, and direct smooth muscle relaxation through other cellular pathways. Some preparations, such as certain herbal products, may have mild antispasmodic effects as well.

Common examples for the gastrointestinal tract include hyoscine butylbromide (buscopan), dicyclomine, mebeverine, and alverine. For urinary symptoms, muscarinic antagonists such as oxybutynin, tolterodine, solifenacin, and trospium are used to reduce detrusor overactivity or bladder spasms. The choice of agent depends on the site of spasm, expected benefit, and tolerability, as well as patient-specific factors.

Indications typically cover relief of abdominal cramps and pain in IBS, as well as bladder or ureteral spasms following surgery or in conditions involving detrusor overactivity. They may be used as short-term adjuncts to diet and other therapies in functional disorders.

Adverse effects are mainly related to anticholinergic activity and can include dry mouth, constipation, blurred vision, and urinary retention. Drowsiness or dizziness may occur with some agents. These drugs are generally contraindicated in conditions where antimuscarinic effects are undesirable, such as narrow-angle glaucoma, significant urinary retention, certain cases of ileus, or severe tachyarrhythmias, and they should be used with caution in elderly patients.