Each tablet contains betahistine dihydrochloride 8 mg.
It also contains the following excipients: β-cyclodextrin, maize starch, microcrystalline cellulose, anhydrous colloidal silica, calcium hydrogen phosphate, povidone, sodium lauryl sulphate, magnesium stearate, purified talc, sodium starch glycolate and purified water.
Pharmacology: Pharmacodynamics: Mechanism Action: Betahistine dihydrochloride is an analog of histamine which can be administered orally. It was developed as one of several β-2-pyridyl alkylamine compounds with actions qualitatively similar to histamine but easier to administer than histamine itself; histamine is ineffective by the oral route. Betahistine is structurally similar to histamine.
The primary clinical indication for betahistine has been Meniere’s disease. Animal studies have demonstrated that betahistine induces histamine-like effects on inner ear microcirculation. Vasodilation of capillaries/arterioles of the spiral ligament and stria vascularis was reported with topical or IV use in guinea pigs and electrical impedance plethysmograph studies suggested increases in cochlear blood flow by over 200% in the same animal model following IV betahistine.
Betahistine has also been evaluated in cerebrovascular disease. Cerebral vasodilation has been reported in animals and humans following oral or IV betahistine, including patients with arteriosclerotic dementia. Oral administration of betahistine 32 mg daily for 1 week was reported to significantly increase cerebral blood flow in patients with ischemic cerebrovascular disease; however, focal decreases in blood flow have also been observed, suggesting intracerebral “steal” may also be operative.
Betahistine appears to act predominantly as a histamine-1 (H1) receptor agonist. However, agonist activity at H2 and H3 receptors has also been reported. In 1 study, cimetidine reversed betahistine-induced relaxation of the rat uterus contracted by acetylcholine; chronotropic effects of betahistine on guinea pig atria were blocked by the H2-receptor antagonist YM11170.
Similar to histamine, reduced blood pressure, headache and flushing occur after IV betahistine administration. However, it is claimed overall to be less toxic than histamine itself. With oral betahistine, gastrointestinal intolerance is the most frequent adverse effect; blood pressure is not generally affected to a significant degree. In contrast to histamine, betahistine has not been reported to significantly increase gastric acid secretion in small studies.
Pharmacokinetics: Pharmacokinetic data for betahistine are limited; Betahist Forte is rapidly absorbed after oral doses and converted to at least 2 metabolites. It is unclear if metabolites are pharmacologically active. Most of a dose is excreted via the urine as metabolites. An elimination half-life (t½) of 3.5 hrs has been reported.
Symptomatic treatment of vertigo associated with Meniere's syndrome.
Adults: Initial Dose: 2 tablets 3 times daily. Maintenance Dose: 3-6 tablets daily.
Administration: To be taken with food.
Symptoms of betahistine overdosage are nausea, vomiting, dyspepsia, ataxia and seizures. More serious complications (convulsion, pulmonary or cardiac complications) were observed in cases of intentional overdose of betahistine especially in combination with other overdosed drugs. No specific antidote. Gastric lavage and symptomatic treatment are recommended.
Hypersensitivity to betahistine dihydrochloride or to any of its excipients. It is contraindicated in the patients with active peptic and phaeochromocytoma.
Caution should be exercised when betahistine dihydrochloride is given to patients with a history of peptic ulcer or asthmatic patients. Concomitant use with antihistamines should be avoided.
Effects on the Ability to Drive and Operate Machinery: Rare reports of drowsiness associated with betahistine have been made. Patients should be advised that if affected, activities requiring concentration, eg, driving and operating machinery should be avoided.
Use in pregnancy & lactation: There is a very limited amount of data available from the use of betahistine in pregnant women. Animal studies, though insufficient do not indicate direct or indirect harmful effects with respect to reproductive toxicity. As a precautionary measure, it is preferable to avoid the use of Betahistine during pregnancy. Insufficient information on the excretion of betahistine in human milk. Betahistine should not be used during breastfeeding.
There is a very limited amount of data available from the use of betahistine in pregnant women. Animal studies, though insufficient do not indicate direct or indirect harmful effects with respect to reproductive toxicity. As a precautionary measure, it is preferable to avoid the use of Betahistine during pregnancy. Insufficient information on the excretion of betahistine in human milk. Betahistine should not be used during breastfeeding.
Immune System Disorders:
Skin rashes and pruritus.
Nervous System Disorders:
Headaches and occasional drowsiness.
Gastrointestinal upset, nausea and dyspepsia.
Skin and Subcutaneous Tissue Disorders:
No proven cases of hazardous interactions. There is a case report of an interaction with ethanol and a compound containing pyrimethamine with dapsone and another of potentiation of betahistine with salbutamol.
Betahistine is a histamine analogue, concurrent administration of H1-antagonists may cause a mutual attenuation of effect of the active agents.
Store at a temperature not exceeding 30°C. Protect from light and moisture.
Shelf-Life: 36 months.
N07CA01 - betahistine ; Belongs to the class of antivertigo preparations.
Tab 8 mg (white, flat, circular, bevelled, uncoated tablets with a breakline on one side and plain on other side) x 10 x 10's.