Betahistine, prescribed for Meniere disease, improves endolymphatic drainage of the inner ear primarily by acting as:

• A H3 receptor agonist and 5-HT3 antagonist
• B H2 receptor agonist and H1 receptor antagonist
• C H1 receptor agonist and H3 receptor antagonist ✓
• D Pure H1 receptor antagonist with vestibular suppressant effect

Explanation

Betahistine is a structural analogue of histamine that acts as a partial agonist at H1 receptors on vestibular vessels, improving microcirculation and resorption in the inner ear, and as an antagonist at presynaptic H3 autoreceptors, which increases hypothalamic histamine release and enhances vestibular compensation. It is neither an H3 agonist nor a conventional vestibular suppressant like the older sedating antihistamines used for motion sickness.

Reference: Katzung's Basic and Clinical Pharmacology, 15th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.