Betahistine Mesylate
Therapeutic Group: Drugs utilized in Meniere's diseases
Pharmacology :
The mechanism of action of betahistine is understood partially. Betahistine features a very strong affinity as an antagonist for histamine H3 receptors and a weak affinity as an agonist for histamine H1 receptors. The active ingredient may be a specific histamine agonist with virtually no H2-activity.
Betahistine has two modes of action. Primarily, it's an immediate stimulating (agonistic) effect on H1 receptors located on blood vessels within the internal ear. It appears to act on the precapillary sphincter within the stria vascularis of the internal ear, thus reducing the pressure within the endolymphatic space.
In addition, betahistine features powerful antagonistic effects at H3 receptors and increases the number of neurotransmitters released from the nerve endings. The increased amounts of histamine released from histaminergic nerve endings stimulate H1 receptors, thus augmenting the direct agonistic effects of betahistine on these receptors. This explains the potent vasodilatory effects of betahistine within the internal ear. This explains the efficacy of betahistine within the treatment of vertigo.
Indications :
Betahistine Mesylate dilates precapillary sphincters, increasing the blood flow within the internal ear. It controls the permeability of capillaries within the internal ear, thereby removes endolymphatic hydrops. It also improves cerebral circulation, increasing blood flow within the internal arteria carotis. Thus, Betahistine Mesylate is clinically useful for the relief of vertigo and dizziness.
Dosage & Administration :
Usually, for adults, administer orally 6 mg to 12 mg 3 times per day after meals. The dose could also be adjusted consistent with the age of the patient and severity of symptoms.
Contraindications :
Hypersensitivity to betahistine mesylate, pheochromocytoma, peptic ulceration, acute asthma.
Side Effects :
Nausea or vomiting may rarely occur. Hypersensitivity reactions, like rash, may rarely occur.
Pregnancy & Lactation :
The safety of Betahistine during pregnancy has not been established. This drug should be administered to pregnant patients or women suspected of being pregnant, as long as the expected therapeutic benefit is assumed to outweigh any possible risk.
Precautions & Warnings :
Patients with a history of digestive ulcer or a lively digestive ulcer, Patients with asthma, Patients with pheochromocytoma.
Storage :
Store in a cool and dry place. Protect from light & moisture.