Agihistine
Agihistine Uses, Dosage, Side Effects, Food Interaction and all others data.
The mechanism of action of betahistine is known partially. Agihistine has a very strong affinity as an antagonist for histamine H3 receptors and a weak affinity as an agonist for histamine H1 receptors. The active ingredient is a specific histamine agonist with virtually no H2-activity.
Agihistine 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.
In addition, betahistine has a powerful antagonistic effects at H3 receptors, and increases the levels of neurotransmitters released from the nerve endings. The increased amounts of histamine released from histaminergic nerve endings stimulates H1 receptors, thus augmenting the direct agonistic effects of betahistine on these receptors. This explains the potent vasodilatory effects of betahistine in the inner ear. This explains the efficacy of betahistine in the treatment of vertigo.
Through its actions on the histamine receptors, betahistine provides relief from vertigo associated with Ménière's disease.
| Trade Name | Agihistine |
| Generic | Betahistine |
| Betahistine Other Names | Betahistina, Bétahistine, Betahistine, Betahistinum |
| Type | |
| Formula | C8H12N2 |
| Weight | Average: 136.1943 Monoisotopic: 136.100048394 |
| Protein binding | The plasma protein binding of betahistine is reported to be less than 5%. |
| Groups | Approved, Investigational |
| Therapeutic Class | Drugs used in meniere's diseases |
| Manufacturer | |
| Available Country | Vietnam |
| Last Updated: | September 19, 2023 at 7:00 am |
Uses
Agihistine Mesilate dilates precapiilary sphincters, increasing the blood flow in the inner ear. It controls the permeability of capillaries in the inner ear, thereby removes endolymphatic hydrops. It also improves cerebral circulation, increasing blood flow in the internal carotid artery. Thus, Agihistine Mesylate is clinically useful for the relief of vertigo and dizziness.
Agihistine is also used to associated treatment for these conditions: Menière's Disease
How Agihistine works
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 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. Agihistine 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. Agihistine 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.
Dosage
Agihistine dosage
Usually for adults, administer orally 6 mg to 12 mg three times per day after meals. The dose may be adjusted according to the age of patient and severity of symptoms.
Side Effects
Nausea or vomiting may rarely occur. Hypersensitivity reactions, such as skin rash, may rarely occur.
Toxicity
Symptoms of an overdose with betahistine (< 640 mg) include dry mouth, nausea, dyspepsia, abdominal pain, and somnolence. Serious complications such as convulsions, pulmonary or cardiac effects may occur with higher doses (> 640 mg), especially during intentional overdoses and combination with other drugs. In the case of an overdose with betahistine, provide supportive therapy, and contact the local poison control center for further management.
Precaution
Patients with a history of digestive ulcer or an active digestive ulcer, Patients with bronchial asthma, Patients with pheochromocytoma.
Food Interaction
- Take with food. This may reduce or prevent gastrointestinal upset.
Volume of Distribution
In a pharmacokinetic study of rats, betahistine was found to be distributed throughout the body. Human data for betahistine's volume of distribution is not readily available.
Elimination Route
When given orally, betahistine is rapidly and almost completely absorbed from the gastrointestinal tract. In the fasted state, Cmax is achieved within 1 hour of administration; in the fed state, Cmax is delayed, but the total drug absorption is similar. Food, therefore, has little effect on the absorption of betahistine.
Half Life
The half-life of betahistine is 3-4 hours.
Elimination Route
Agihistine is mainly excreted in the urine; with approximately 85-91% being detected in urine samples within 24 hours of administration.
Pregnancy & Breastfeeding use
Safety of Agihistine during pregnancy has not been established. This drug should be administered to pregnant patients or women suspected of being pregnant, only if the expected therapeutic benefit is thought to outweigh any possible risk.
Contraindication
Hypersensitivity to betahistine mesylate, pheochromocytoma, peptic ulcer, acute bronchial asthma.
Storage Condition
Store in cool and dry place. Protect from light & moisture.
Innovators Monograph
You find simplified version here Agihistine
FAQ
What is Agihistine used for?
Agihistine is a medicine used to treat the symptoms of Ménière's disease. Symptoms include: dizziness (vertigo) ringing in the ears (tinnitus). Agihistine is an anti-vertigo medication. It is commonly prescribed for balance disorders or to alleviate vertigo symptoms.
How safe is Agihistine?
Agihistine is unlikely to do you any harm, even if you take it for a long time. It is generally a very safe medicine.
How does Agihistine work?
Agihistine works by increasing the effect of a natural substance called histamine in your inner ear. Antihistamines work by stopping histamine affecting the cells in your body.
What are the common side effects of Agihistine?
Common side effects of Agihistine are Headache, occasional drowsiness, nausea, indigestion, mild gastric complaints such as vomiting, stomach pain and bloating.
Is Agihistine safe during pregnancy?
Agihistine is not usually recommended during pregnancy .
Is Agihistine safe during breastfeeding?
Agihistine is not usually recommended while breastfeeding.
Can I drink alcohol with Agihistine?
Yes, you can drink alcohol while taking Agihistine. However, some people say that their symptoms of Ménière's disease improve when they stop drinking alcohol.
Can I drive after taking Agihistine ?
Agihistine is not likely to affect your ability to drive or ride a bike. However, do not drive if you feel dizzy or if you feel an attack of vertigo coming on.
How long does Agihistine stay in my system?
Agihistine comes in both a tablet form as well as an oral solution, and is taken orally. The mean plasma elimination half-life is 3 to 4 hours, and excretion is virtually complete in the urine within 24 hours.
When should be taken of Agihistine?
It's best to take your tablets with or after food. This way it's less likely to upset your stomach.
Does Agihistine cure vertigo?
Our findings suggest that Agihistine therapy is effective in treating vertigo in routine clinical settings.
Can I take Agihistine for a long time?
Agihistine is unlikely to do you any harm, even if you take it for a long time. It is generally a very safe medicine.
How long can I take Agihistine?
Your doctor may advise a trial of Agihistine for 6-12 months to see if it helps to reduce your symptoms. If it does, it can then be continued.
Who should not take Agihistine?
Agihistine dihydrochloride tablets are not recommended for use in children and adolescents below 18 years of ages, as there are no data on efficacity and safety in these age groups.
Can I suddenly stop taking Agihistine?
Do not give this medicine to anyone else, even if they have the same condition as you. Do not stop taking Serc, or change the dosage, without checking with your doctor.
What happens if I miss a dose of Agihistine?
If you forget to take a dose of Agihistine, take it as soon as you remember. Unless it's less than 2 hours until your next dose. In which case, skip the missed dose and take your next dose at the usual time. Do not take 2 doses at the same time.
What happens if I take too much Agihistine?
The symptoms of Agihistine overdose are nausea, vomiting, dyspepsia, ataxia and seizures at higher doses. A few overdose cases have been reported. Some patients experienced mild to moderate symptoms with doses up to 640 mg.
Can Agihistine affect my fertility ?
There's no firm evidence to suggest that taking Agihistine will reduce fertility in either men or women. However, speak to a pharmacist or your doctor before taking it if you're trying to get pregnant.
Does Agihistine cause hypertension?
As Agihistine is a synthetic analogue of histamine it may induce the release of catecholamines from the tumor resulting in severe hypertension.
Can Agihistine affect liver?
Agihistine has a strong first pass effect and is metabolised in the liver into three metabolites, not only Agihistine but also its major metabolite aminoethylpyridine increases cochlear blood flow.
