Adult: For the treatment of vertigo, tinnitus, hearing loss, and nausea associated with Meniere's disease: As betahistine dihydrochloride: Initially, 8-16 mg tid. Maintenance: 24-48 mg daily in divided doses. As betahistine mesilate: 6-12 mg tid. Adjust doses according to patient needs.
What are the brands available for Betahistine in Hong Kong?
Symptoms: Nausea, somnolence, abdominal pain; convulsions, pulmonary or cardiac complications. Management: Supportive and symptomatic treatment. Perform gastric lavage.
Drug Interactions
Metabolism may be inhibited by MAOIs (e.g. selegiline). May diminish efficacy with antihistamines.
Food Interaction
Delayed absorption with food.
Action
Description: Mechanism of Action: Betahistine is a histamine analogue that is claimed to improve the microcirculation of the labyrinth resulting in decreased endolymphatic pressure. The exact mechanism is not yet fully determined; however, it is known to act as both a partial histamine H1-receptor agonist and histamine H3-receptor antagonist in neuronal tissue, with negligible histamine H2-receptor activity. It inhibits presynaptic histamine H3-receptors and induces H3-receptor downregulation, thus increasing the histamine turnover and release. Pharmacokinetics: Absorption: Readily and almost completely absorbed from the gastrointestinal tract. Delayed absorption with food. Time to peak plasma concentration: 1 hour (inactive metabolite). Distribution: Plasma protein binding: <5%. Metabolism: Rapidly and almost completely metabolised into 2-pyridylacetic acid (inactive metabolite). Excretion: Via urine (approx 91%; mainly as inactive metabolite). Elimination half-life: Approx 3.5 hours (inactive metabolite).
Chemical Structure
Betahistine Source: National Center for Biotechnology Information. PubChem Database. Betahistine, CID=2366, https://pubchem.ncbi.nlm.nih.gov/compound/Betahistine (accessed on Jan. 21, 2020)
Storage
Store between 15-30°C. Protect from moisture and light.