Which anticholinergic is used to treat diarrhea?

• A. Atropine
• B. Scopolamine
• C. Methscopolamine
• D. Glycopyrrolate

Answer: (B)

Blocking muscarinic receptors in the gut reduces parasympathetic stimulation, which slows intestinal movements and lowers secretions. This relief from intestinal cramping and hypermotility is how anticholinergics help with diarrhea. Among the options, scopolamine is a potent antimuscarinic with strong effects on intestinal smooth muscle, making it a classic antispasmodic for GI cramping and diarrhea relief. The other drugs are either less focused on GI spasm, have broader systemic actions, or are used mainly for different indications, so they’re not as effective for treating diarrhea in typical scenarios. Side effects to watch for include dry mouth, urinary retention, and potential CNS effects due to central muscarinic blockade.