Merislon Mechanism of Action

Merislon dilates pre-capillary sphincters thus increasing the blood flow in the inner ear. It controls the permeability of capillaries in the inner ear, thereby removing endolymphatic hydrops. It also improves cerebral circulation, increasing blood flow in the internal carotid artery. MERISLON is clinically useful for the relief of vertigo and dizziness.
Pharmacology: Pharmacodynamics: Improvement of circulatory disturbances in the inner ear: In the inner ear of the guinea pig with experimentally-induced microcirculatory disturbances, the blood flow increases to 148% of the control level within 30 min after the intraperitoneal injection of betahistine mesilate. This effect is specific for pathological conditions.
Increase of blood flow in the scala media of guinea pigs with endolymphatic hydrops: When betahistine mesilate was administered to guinea pigs with endolymphatic hydrops, it produced a significant increase in blood flow in the scala media. The blood flow increased significantly from 5.5 mL/min/100 mg to 8.1 mL/min/100 g. It is considered that the increase in blood flow is due to relaxation of smooth muscle of the cochlear radial arteria.
Improvement of intracerebral blood flow: In the experiment in rhesus monkeys, betahistine mesilate after intravenous administration increases blood flow in the cerebral and cerebellar tissues from 70.4 to 81.4 mL/min/100 g/min and 73.2 to 84.0 mL/min/100 g/min, respectively.
Clinical Studies: Clinical efficacy: In clinical trials on a total of 875 patients including double blind clinical trials, it has been demonstrated that MERISLON is useful for relieving dizziness or feeling of dizziness associated with Meniere's disease, Meniere's syndrome or vertigo, etc.
Pharmacokinetics: Betahistine mesilate was administered orally to 20 healthy adult male volunteers at a single dose of 24 mg. The main metabolic product was 2-pyridylacetic acid and its plasma concentration was determined. The time to reach the peak plasma concentration (T_max) was 0.98±0.47 h, the peak plasma concentration (C_max) was 339.4±213.4 ng/ml, eliminated half-life (t_½) was 5.17±2.66 h and the area under the plasma concentration-time curve (AUC_0-t) was 1,153±729 ng·h/ml.