AGIHISTINE®8

Composition: Each tablet contains:
Betahistine dihydrochloride. . . . . . . . . . . . . 8 mg
Presentation:
5 blisters of 20 tablets in a carton box.
Indications:
Treatment of Ménière’s syndrome with three basic symptoms:
– Vertigo (accompanied by nausea, vomiting).
– Impaired hearing.
– Tinnitus.
Treatment of symptoms of vertigo due to vestibular dysfunction.

Category:

Additional information

Dosage and administration

Dosage:
Initial dose: 1 – 2 tablets x 3 times daily.
Maintenance doses are generally in the range 24 – 48 mg daily.
Duration of treatment is 2-3 months.
The dose should be adjusted according to the age and severity of the disease.
Administration:
Agihistine® 8 tablets are taken orally and preferably during meals to avoid gastrointestinal disorders.

Contraindications

Hypersensitivity to betahistine or any component of the product.
Gastroduodenal ulcers.
Pheochromocytoma.
Children under 18 years old.

Warnings and precautions for use

Agihistine® 8 tablets induce histamine-like effects; therefore, caution should be taken in the following cases:
– Patients with peptic ulcers or a history of peptic ulceration.
– Patients with bronchial asthma because betahistine causes bronchospasm.
– Patients with pheochromocytoma.
– The elderly: At this age, due to decreased functional physiological activities, dose reduction and closely monitoring are recommended.
– Children: The safety of this medicine for children has not been established.
– Agihistine® 8 tablets contain lactose. Patients with rare hereditary problems of galactose intolerance, lactase enzyme deficiency or glucose-galactose malabsorption should not take this medication.

Recommendation for pregnancy and breastfeeding

The safety of betahistine in human pregnancy has not been completely established. This medicine should be used during pregnancy or lactation only if the expected therapeutic benefit is thought to outweigh any possible risk.

Effects on ability to drive and use machines

There is no information on the effect of betahistine on driving and using machinery.

Interactions, incompatibilities of medicine

There are no proven cases of hazardous interactions. However, since betahistine has structurally similar to histamine, interaction with antihistamines may occur.

Undesirable effects (ADRs)

Agihistine® 8 is well tolerated, so it can be used for a long time. Relatively few side effects have been reported.
– Rare: Mild stomach pain (which can be avoided by taking the drug with meals or reducing doses), nausea, vomiting, dyspepsia.
– Very rare: Rash, pruritus, headache, somnolence.

Overdose and management

Symptoms of overdose: Nausea, vomiting, dyspepsia; ataxia and seizures at higher doses.
Management:
+ There is no specific antidote.
+ Overdose treatment includes gastric lavage and symptomatic treatment.

Pharmacodynamic properties

Antivertigo drug.
The precise mechanism of therapeutic action of betahistine is still not completely understood. However, in vitro, betahistine facilitates histamine conduction due to partial agonist action at H1 receptors, and antagonist action at H3 receptors.
Betahistine relaxes precapillary sphincter, so it increases the circulation of the inner ear. It controls the permeability of capillaries in the inner ear thereby reduces endolymphatic hydrops. It also improves cerebral circulation, increases blood flow in the internal carotid artery and vertebral arteries. Therefore, betahistine is clinically effective in the treatment of vertigo and dizziness.

Pharmacokinetic properties

After oral administration, betahistine is rapidly and completely absorbed from the gastrointestinal tract. The drug is rapidly metabolised to one major metabolite 2-pyridylacetic acid and excreted in the urine.
The half-life is about 3.5 hours.
The dose is almost completely excreted in the urine in about 24 hours.

Storage conditions, shelf-life, quality specification of the medicine

Storage conditions: Protect from humidity and light, below 30 degrees C.
Shelf – life: 36 months from the manufacture date.
Quality specification: In house specification.