Adult: For vertigo, tinnitus and hearing loss associated in patients with Meniere’s disease: As betahistine dihydrochloride: Initially, 8-16 mg tid or 24 mg bid, adjusted according to individual response. Maintenance: 24-48 mg daily. Max: 48 mg daily. As betahistine mesilate: 6-12 mg tid.
May be taken with or without food.
Chống chỉ định
Patients with bronchial asthma, CV disease, active or history of peptic ulcer disease. Hepatic impairment. Pregnancy and lactation.
Phản ứng phụ
Significant: Rarely, ventricular extrasystoles, hypotension (including orthostatic hypotension), tachycardia. Gastrointestinal disorders: Nausea, dyspepsia. Rarely, vomiting, bloating, abdominal distension or pain. General disorders and admin site conditions: Rarely, fatigue, malaise. Immune system disorders: Hypersensitivity reactions (e.g. anaphylaxis). Rarely, urticaria. Nervous system disorders: Headache. Rarely, dizziness, convulsions, somnolence. Psychiatric disorders: Rarely, confusion, hallucination. Respiratory, thoracic and mediastinal disorders: Rarely, dyspnoea, bronchospasm. Skin and subcutaneous tissue disorders: Rarely, rash, pruritus. Vascular disorders: Rarely, vasodilation.
Serum concentration may be increased by MAOIs (e.g. selegiline). Therapeutic effects may be decreased by antihistamines. May decrease the bronchodilator effects of β2 agonists.
Delayed absorption with food.
Description: Betahistine is a histamine analogue. The exact mechanism is not yet fully determined; however, it is known to act as both partial histamine H1-receptor agonist and histamine H3-receptor antagonist in neuronal tissue, with negligible histamine H2-receptor activity. It may also improve the microcirculation in the labyrinth, thus reducing endolymphatic pressure. Pharmacokinetics: Absorption: Rapidly and completely absorbed from the gastrointestinal tract. Delayed absorption with food. Time to peak plasma concentration: 1 hour (2-pyridylacetic acid). Distribution: Plasma protein binding: <5%. Metabolism: Rapidly and almost completely metabolised in the liver to its inactive metabolite, 2-pyridylacetic acid. Excretion: Via urine (Approx 91%, mainly as inactive metabolite). Elimination half-life: Approx 3.5 hours (2-pyridylacetic acid).
Store below 25°C. Protect from moisture and light.