dicyclomine

By blocking M3 muscarinic receptors on gastrointestinal smooth muscle, dicyclomine reduces the amplitude of contractions and relieves cramping; it also has some direct smooth muscle relaxant activity. It is used for the pain and cramping of diarrhoea-predominant irritable bowel syndrome, usually taken before meals, and is not a treatment for the underlying disorder. Because muscarinic blockade is not selective for the gut, systemic effects follow the classic mnemonic of dry as a bone, blind as a bat, red as a beet, hot as a hare, and mad as a hatter, and the elderly are especially vulnerable to confusion and delirium; dicyclomine appears on the Beers list of medications to avoid in older adults. Contraindications include narrow-angle glaucoma, myasthenia gravis, obstructive uropathy including benign prostatic hyperplasia, paralytic ileus, toxic megacolon, ulcerative colitis, and reflux oesophagitis. It is contraindicated in breastfeeding and in infants under six months because of reports of apnoea. Antidote for severe antimuscarinic toxicity is physostigmine.