skopolamin

Scopolamine, also called hyoscine, is a tropane alkaloid that acts as a competitive antagonist of muscarinic acetylcholine receptors. It is derived from plants of the Solanaceae family, such as Datura, Hyoscyamus, and Atropa. By blocking parasympathetic signals, scopolamine reduces secretions and modulates smooth muscle activity, particularly in the gut and vestibular system. It can cross the blood-brain barrier, producing central nervous system effects.

Medical uses include prevention of motion sickness and prevention of postoperative nausea and vomiting. It is available in several forms: oral or injectable preparations for immediate or short-term effects, and a transdermal patch that delivers a steady dose over about 72 hours. The patch is commonly used for preventing motion sickness or for preoperative medication to reduce salivation and secretions.

Pharmacology and duration vary by route. The transdermal patch provides gradual absorption and a longer-lasting effect, while oral or injectable forms act more quickly but for a shorter period. Scopolamine is often preferred when anticholinergic side effects such as dry mouth, blurred vision, and urinary retention are manageable risks.

Safety and contraindications are important. Scopolamine can cause drowsiness, confusion, and memory impairment, especially in older adults or at higher doses. It is contraindicated in narrow-angle glaucoma and cautioned in patients with cognitive impairment, urinary retention, or certain electrolyte imbalances. Interactions with other anticholinergic drugs, sedatives, or alcohol can enhance adverse effects.

In some contexts, scopolamine has been misused as an incapacitating agent, though medical use relies on controlled, therapeutic dosing.