ZISTIN-16 TAB

THIS COMPOUND BELONGS TO THE CLASS OF ORGANIC COMPOUNDS KNOWN AS ARALKYLAMINES. THESE ARE ALKYLAMINES IN WHICH THE ALKYL GROUP IS SUBSTITUTED AT ONE CARBON ATOM BY AN AROMATIC HYDROCARBYL GROUP.

PHARMACOLOGY
PHARMACODYNAMICS:

Betahistine primarily acts as a histamine H1-agonist with 0.07 times the activity of histamine. Stimulating the H1-receptors in the inner ear causes a vasodilator effect and increased permeability in the blood vessels which results in reduced endolymphatic pressure. Betahistine is believed to act by reducing the asymmetrical functioning of sensory vestibular organs as well as by increasing vestibulocochlear blood flow. Doing so aids in decreasing symptoms of vertigo and balance disorders. Betahistine also acts as a histamine H3-receptor antagonist which causes an increased output of histamine from histaminergic nerve endings which can further increase the direct H1-agonist activity. Furthermore, H3-receptor antagonism increases the levels of neurotransmitters such as serotonin in the brainstem, which inhibits the activity of vestibular nuclei, helping to restore proper balance and decrease in vertigo symptoms.

PHARMACOKINETICS:

• Absorption: – When given orally, betahistine is rapidly absorbed from the gastrointestinal tract.
• Half-Life: – The mean plasma half-life is 3–4 hours, and
• Excretion: – Excretion is virtually complete in the urine within 24 hours.
• Protein Binding: – Plasma protein binding is very low. Betahistine is transformed into aminoethylpyridine and hydroxyethylpyridine and excreted with the urine as pyridylacetic acid. There is some evidence that one of these metabolites, aminoethylpyridine, may be active and exert effects similar to those of betahistine on ampullar receptors.

INDICATIONS:

For the reduction of episodes of vertigo association with Ménière’s disease