Synthetic analog of histamine, has a histamine-like and vasodilating effect. Is a weak agonist H1receptors and a rather potent H antagonist3receptors. Affects the cochlear blood flow and central vestibular apparatus.
The action of betagistin includes: vasodilation in the inner ear (indirectly through H3 and H1receptors), the inhibitory effect on vestibular nuclei (via H3receptors) and impulsive activity of ampullar receptors. By direct agonistic action on H1receptors of the vessels of the inner ear and precapilar sphincters of the microcirculatory bed located in the vascular stripe (stria vascularis), and also indirectly through H3-receptors improves microcirculation and permeability of capillaries, normalizes the pressure of the endolymph in the labyrinth and cochlea, increases blood flow in the basilar artery.
Has a pronounced central effect, being an antagonist of H3receptors of the nuclei of the vestibular nerve, normalizes neuronal transmission in the polysynaptic neurons of the vestibular nuclei at the level of the brainstem. Influencing H indirectly3receptors, increases the content of serotonin in the brain stem, which reduces the activity of the vestibular nuclei.
Helps eliminate violations from both the vestibular and cochlear apparatus: reduces the frequency and intensity of dizziness, reduces tinnitus, helps improve hearing in cases of its decline.
Stimulates H1receptors, so it does not have a sedative effect and does not cause drowsiness.