Betahistine hydrochloride.
Each tablet contains: Betahistine hydrochloride 8 mg, 16 mg or 24 mg.
Pharmacology: Pharmacodynamics: Mechanism of Action: Betahistine has a direct stimulating (agonistic) effect on H1 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 give rise to local vasodilation and increased permeability, which would help reverse the underlying problem of 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.
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.
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.
Hypersensitivity to Betahistine.
Betahistine should not be given to patients with phaeochromocytoma. It should be given with care to patients with asthma, peptic ulcer disease or a history of peptic ulcer disease.
Betahistine is considered to be unsafe in patients with porphyria because it has been shown to be porphyrinogenic in in-vitro systems.
Use in Pregnancy: The safe use of Betahistine during pregnancy has not been established, thus, Betahistine may only be used if potential benefit justifies potential risk to fetus.
Gastrointestinal disturbances, headache, skin rashes and pruritus have been reported.
Beta-2 agonists: Effects may be decreased by betahistine (due to bronchoconstrictive or other smooth muscles effects). Histamine antagonists: H1 antagonists may decrease response to betahistine. H2 blockers would not be expected to interfere with activity.
Store at temperatures not exceeding 30°C.
N07CA01 - betahistine ; Belongs to the class of antivertigo preparations.
Overt tab 16 mg
100's (P2,506.84/box)
Overt tab 8 mg
100's (P1,767.92/box)