O-VERT (BETAHISTINE hydrochloride) 8 mg & 16 mg TABLET

Transcription

1 O-VERT (BETAHISTINE hydrochloride) 8 mg & 16 mg TABLET ANTI-VERTIGO Page 1 of 5

2 BETAHISTINE HYDROCHLORIDE STRUCTURAL FORMULA MOLECULAR WEIGHT MOLECULAR FORMULA C 8 H 14 Cl 2 N 2 CHEMICAL NAME N-Methyl-2-(2-pyridinyl)ethanamine hydrochloride CLINICAL PHARMACOLOGY Mechanism of action Betahistine has a direct stimulating (agonistic) effect on H 1 receptors located on blood vessels in the inner ear. Betahistine dilates the blood vessels within the middle ear which can relieve pressure from excess fluid and act on the smooth muscle. This would five rise to local vasodilation and increased permeability, which would help reverse the underlying problem of Page 2 of 5

3 endolymphatic hydrops (the main pathological feature is an excess of endolymph fluid producing an increase in pressure in the membranous labyrinth). PHARMACOKINETICS Absorption is rapid and complete. It undergoes hepatic metabolism, and its elimination half-life is 3.4 hours via urine as inactive metabolites. INDICATIONS Betahistine is an analogue of histamine and is claimed to improve the microcirculation of the labyrinth resulting in reduced endolymphatic pressure. It is used to reduce the symptoms of vertigo, tinnitus, and hearing loss associated with Meniere s disease. DOSAGE AND ADMINISTRATION The usual initial dose is 8 mg to 16 mg three times daily taken preferably with meals; maintenance doses are generally in the range of 24 to 48 mg daily. CONTRAINDICATIONS Use in patients with hypersensitivity to betahistine hydrochloride or any component of the tablet. Betahistine should not be given to patients with phaeocromocytoma. PRECAUTIONS Betahistine should be given with care to patients with asthma, peptic ulcer disease or a history of peptic ulcer disease. ADVERSE EFFECTS Gastrointestinal disturbance, headache, skin rashes and pruritus have been reported. Page 3 of 5

4 DRUG INTERACTIONS Beta 2 agonists: Effects may be decreased by betahistine (due to bronchoconstrictive or other smooth muscle effects). Histamine antagonists: H 1 antagonists may decrease response to betahistine. H 2 blockers would not be expected to interfere with activity. PREGNANCY AND LACTATION The use of betahistine during pregnancy has not been established, thus, betahistine may only be used if potential benefit justifies potential risk to fetus. PHARMACEUTICAL INFORMATION Drug Product O-VERT 8 mg Tablet Description of product White, round tablet plain on both sides; Diameter = 8mm; Thickness = 2.50 mm ± 0.2 mm FDA Registration No. DR-XY37169 Classification Ethical Drug Essential Drug List Yes O-VERT 16 mg Tablet Description of product White, round tablet scored on one side, plain on the other side; Diameter =10 mm; Thickness = 2.78 mm ± 0.2 mm FDA Registration No. DR-XY37175 Classification Ethical Drug Essential Drug List Yes Page 4 of 5

5 Composition Active Betahistine hydrochloride Inactive Mannitol Pharmacological category ANTI-VERTIGO Storage condition Store at temperature not exceeding 30 o C. Availability Betahistine hydrochloride (O-VERT) 8 mg Tablet: Alu/Alu strip foul x 10 s (Box of 30 s and 100 s) Betahistine hydrochloride (O-VERT) 16 mg Tablet: Alu/Alu strip foul x 10 s (Box of 30 s and 100 s) References: Sweet, Sean C, Martindale 36st edition, (London, Chicago 2009) Page 5 of 5