Which antimuscarinic alkaloid is preferred over atropine for prophylaxis of motion sickness because of its greater central nervous system penetration?
- A Homatropine
- B Ipratropium
- C Scopolamine ✓
- D Tropicamide
Correct answer: C. Scopolamine
Explanation
Scopolamine is a tertiary amine that crosses the blood brain barrier readily and suppresses vestibular inputs at central muscarinic sites, making it the classic transdermal agent for motion sickness. It also produces sedation and amnesia at higher doses. Ipratropium is a quaternary ammonium compound confined topically to the airway, so it cannot reach vestibular centres. Homatropine and tropicamide are ophthalmic agents whose durations suit mydriasis rather than vestibular suppression.
Reference: Katzung's Basic and Clinical Pharmacology, 15th ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
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