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.
Cách dùng
May be taken with or without food.
Chống chỉ định
Phaeochromocytoma, active or history of peptic ulcer.
Thận trọng
Patient with bronchial asthma, CV disease, urticaria, rashes, allergic rhinitis. Patient taking antihistamines. Hepatic impairment. Pregnancy and lactation.
Symptoms: Nausea, somnolence, abdominal pain; convulsions, pulmonary or cardiac complications. Management: Supportive and symptomatic treatment. Perform gastric lavage.
Tương tác
Metabolism may be inhibited by MAOIs (e.g. selegiline). May diminish efficacy with antihistamines.
Tương tác với thức ăn
Delayed absorption with food.
Tác dụng
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).
Đặc tính
Bảo quản
Store between 15-30°C. Protect from moisture and light.