Which of the following best describes the pharmacological action of betahistine used in Meniere's disease?

• A H2 receptor antagonism reducing endolymph production by the stria vascularis
• B Direct vasodilatation of the internal auditory artery through calcium channel blockade
• C H3 receptor antagonism that increases hypothalamic histamine release and improves inner ear microcirculation ✓
• D Selective vestibular suppressant action on type I hair cells

Explanation

Betahistine acts as a potent H3 receptor antagonist and weak H1 agonist. H3 blockade increases histamine synthesis and release from the tuberomammillary nucleus, improving vestibular microcirculation and promoting central compensation, while H1 agonism produces mild vasodilatation. It does not block calcium channels, does not act on H2 receptors of the stria vascularis, and has no direct hair cell suppressant action. It is first line therapy for reducing vertigo attack frequency in Meniere's disease.

Reference: Dhingra, Diseases of Ear, Nose and Throat, 8th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.