Menaril

The usual initial dose: 8 mg to 16 mg three times daily taken preferably with meals.

Maintenance dose: Up to 48 mg daily has been recommended. Betahistine is not recommended for use in children.

Betahistine is generally well tolerated and there is no known serious adverse effects. In some circumstances gastrointestinal disturbances, headache, rashes and pruritus have been reported.

Meniere's disease and Meniere-like syndromes are characterized by attacks of vertigo, tinnitus and/or progressive loss of hearing, usually accompanied by nausea and vomiting.

The mechanism of action of betahistine is multifactorial. Meniere's disease is thought to result from a disruption of endolymphatic fluid homeostasis in the ear. Betahistine mainly acts as a histamine H1-receptor agonist. The stimulation of H1-receptors in the inner ear causes a vasodilatory effect leading to increased permeability of blood vessels and a reduction in endolymphatic pressure; this action prevents the rupture of the labyrinth, which can contribute to the hearing loss associated with Ménière's disease. Betahistine is also purported to act by reducing the asymmetrical functioning of sensory vestibular organs and increasing vestibulocochlear blood flow, relieving symptoms of vertigo.

In addition to the above mechanisms, betahistine also acts as a histamine H3-receptor antagonist, increasing the turnover of histamine from postsynaptic histaminergic nerve receptors, subsequently leading to an increase in H1-agonist activity. H3-receptor antagonism elevates levels of neurotransmitters including serotonin in the brainstem, inhibiting the activity of vestibular nuclei, thus restoring proper balance and decreasing vertigo symptoms.

Caution should be exercised in patients with bronchial asthma and peptic ulceration.

Drugs used in meniere's diseases