Betahistine

**Semantic type:** Pharmacologic Substance

**Definition:** A histamine analog with weak histamine H1 agonistic and more potent histamine H3 antagonistic properties. Upon intranasal administration, betahistine binds to histamine H1 and H3 receptors and exerts its agonistic and antagonistic actions locally and centrally. This promotes cochlear, vestibular and cerebral blood flow, decreases neuronal firing in the vestibular nuclei and increases histamine synthesis and release in the brain which facilitates vestibular compensation. Increased blood flow around the inner ear reduces the amount of fluid in the inner ear and may alleviate vertigo, tinnitus, and hearing loss.

**Synonyms:** - BETAHISTINE