Skip to main content

BETAHISTINE Uses, Side Effects, and More

 BETAHISTINE


BRAND NAME:- VERTIN 8mg  tab .


BETAHISTINE is an orally active,somewhat H1 selective Histamine analogue, which is used to control vertigo in patients of Meniere's disease: possibly acts by causing vasodilation in the internal ear. It is contraindicated in asthmatics and ulcer patients.

PHARMACODYNAMIC:-

Betahistine is a strong antagonist of the histamine H3 receptor and a weak agonist of the histamine H1 receptor.[1]
Betahistine has two mechanisms of action. Primarily, it is a weak agonist on the H1 receptors located on blood vessels in the inner ear. This gives rise to local vasodilation and increased permeability, which helps to reverse the underlying problem of endolymphatic hydrops.
More importantly, betahistine has a powerful antagonistic effects at H3 receptors, thereby increasing the levels of neurotransmitters histamine, acetylcholine, norepinephrine, serotonin, and GABA released from the nerve endings. The increased amounts of histamine released from histaminergic nerve endings can stimulate receptors. This stimulation explains the potent vasodilatory effects of betahistine in the inner ear, that are well documented.
Betahistine seems to dilate the blood vessels within the inner ear which can relieve pressure from excess fluid and act on the smooth muscle.
It is postulated that betahistine's increase in the level of serotonin in the brainstem inhibits the activity of vestibular nuclei. 

PHARMACOKINETICS:-

Betahistine comes in both a tablet form as well as an oral solution, and is taken orally. It is rapidly and completely absorbed. The mean plasma elimination half-life is 3 to 4 hours, and excretion is virtually complete in the urine within 24 hours. 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. 

MECHANISM OF ACTION:-

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.3 In 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 recurrence of vertigo symptoms. This significantly impacts the quality of life and the ability to carry out daily activities.

H1-RECEPTOR ACTIVITY 

The mechanism of action of betahistine is multifactorial. Ménière's disease is thought to result from a disruption of endolymphatic fluid homeostasis in the ear.6 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.

H3-RECEPTOR ACTIVITY 

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. 

USED:-

Betahistine is used for Meniere's disease. It helps to reduce the episodes of vertigo associated with Meniere's disease. 


SIDE effects:-

Headache, Nausea, Palpitations.


DOSE:- ½ TO 1 tab OD.

Comments

Popular posts from this blog

Chlorthalidone Uses, Side Effects, and More....

 Chlorthalidone  Brand name:- Hythalton 50,100mg , Hydrazide, Thalizide ( 12.5, 25) . Chlorthalidone is a diuretic which lowers blood pressure by removing extra water and certain electrolytes from the body. Over time it also relaxes blood vessels and improves blood flow. Pharmacodynamic:- Not 🚫 available.  Pharmacokinetics:- Chlortalidone is slowly absorbed from the gastrointestinal tract after oral ingestion. It has a long half-life and therefore a prolonged diuretic action, which results in continued diuretic effects despite a skipped dose. This prolonged action of chlortalidone despite missing doses may account for the higher efficacy of chlortalidone compared to the shorter half-life medication, hydrochlorothiazide. Chlortalidone is eliminated from the body mostly by the kidney, as unchanged drug. Thus, in persons with diminished kidney function, the clearance of chlortalidone is reduced and the elimination half-life is increased. As with other thiazide diuretics, ch...

Chlordiazepoxide Uses, Side Effects, and More

 Chlordiazepoxide Brand name:- Librium 10, 25 mg tabs; Equilibrium 10mg tab. Chlordiazepoxide is a benzodiazepine. It works by increasing the action of a chemical messenger (GABA) which suppresses the abnormal and excessive activity of the nerve cells in the brain. Pharmacodynamic:-  Chlordiazepoxide has antianxiety, sedative, appetite-stimulating and weak analgesic actions. The drug seems to block EEG arousal from stimulation in the brain stem reticular formation. The drug has been studied extensively in many species of animals and these studies are suggestive of action on the limbic system of the brain, which recent evidence indicates is involved in emotional responses. Hostile monkeys were made tame by oral drug doses which did not cause sedation. Chlordiazepoxide revealed a "taming" action with the elimination of fear and aggression. The taming effect of chlordiazepoxide was further demonstrated in rats made vicious by lesions in the septal area of the brain. The drug dos...

Know details about Dabigatran etexilate drug ?

 Dabigatran Etexilate