Which anticholinergic is used to treat diarrhea and is structurally related to scopolamine?

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

Answer: (C)

Blocking acetylcholine’s action in the gut can slow intestinal movements and reduce secretions, helping to control diarrhea. Methscopolamine is a scopolamine-related anticholinergic that is designed to work mainly in the gastrointestinal tract. Its structure limits penetration into the central nervous system, so it delivers the antimuscarinic effect peripherally with fewer CNS side effects. This gut-focused action makes it the preferred option for treating diarrhea among the choices.

Other drugs listed are either more central-acting or used for different indications. Scopolamine mainly treats motion sickness with strong CNS effects; atropine is a broad antimuscarinic with widespread effects; glycopyrrolate is antimuscarinic used for reducing secretions or perioperative care but not specifically indicated for diarrhea.