Betahistine 16mg
Betahistine has two modes of action. Primarily, it has a direct stimulating (agonistic) effect on H1 receptors located on blood vessels in the inner ear. It appears to act on the precapillary sphincter in the stria vascularis of the inner ear, thus reducing the pressure in the endolymphatic space. Ménière's disease is a progressive disease of the inner ear characterized by vertigo, tinnitus, and hearing loss. It has a significant impact on both the psysical and social functioning of affected individuals.
Betahistine is a histamine-like antivertigo drug used for treating symptoms associated with Ménière's disease. It is actions on histamine receptors. Vertigo is a disturbing sensation of movement caused by dysfunction of the labyrinth (inner ear), vestibular nerve, cerebellum, brainstem, or Central Nervous System (CNS). Vestibular forms of vertigo are often accompanied by auditory dysfunctions such as hyperacusis, hearing loss, and tinnitus. In the most cases, adaptive mechanisms of the CNS lead to functional recovery after episodes of vertigo, however, syndromes such as Ménière's disease tend to cause the significantly impacts the quality of life and the ability to carry out daily activities.
The mechanismof action of Betahistine is multifactorial. Ménière's disease is thought to result from a disruption of endolymphatic fluid homeostasis in the ear. Betahistinemainly 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.
The plasma protein binding of Betahistine is reported to be less then 5%.
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.
Betahistine is metabolized primarily into the inactive metabolite 2-pyridylacetic acid. There is both clinical and vitro evidence that monoamine oxidase enzymes are responsible for the metabolism of Betahistine.
Feeling sick ( nausea) indigestion (acid reflux) bloating or mild stomach ache and headache
