BETAHISTINE PILLS 16MG

Composition:

1 pill (16 mg) contains:
active ingredient: betahistine dihydrochloride - 16 mg
excipients: lactose monohydrate, microcrystalline cellulose,
Magnesium stearate, colloidal silicon dioxide, corn starch

DESCRIPTION

pills white or white with a yellowish tinge color. Mild marbling is allowed. pills of 8 mg - round, biconvex, without risks, 16 mg - round, biconvex, with risk. pills 24 mg - round, flat-cylindrical, with risk and a facet.

Pharmacodynamics

The mechanism of action of betahistine is only partially known. There are several possible hypotheses, confirmed by preclinical and clinical data:

Effect on histaminergic system:
The partial antagonist of the H1-histamine antagonist of the H3-histamine receptors of the vestibular nuclei of the central nervous system (CNS), has little activity against the H2 receptors. Betahistine increases histamine metabolism and its release by blocking presynaptic H3 receptors and reducing the number of H3 receptors.

Strengthening the blood flow of the cochlear region, as well as the entire brain:
According to preclinical studies, betahistine improves blood circulation in the vascular strip of the inner ear by relaxing the irscapillary sphincter of the inner ear vessels.It is also shown that betahistine increases the blood flow to the brain in humans.
Facilitating the process of central vestibular compensation
Betahistine accelerates the restoration of vestibular function in animals after unilateral vestibular neurolectomy, accelerating and facilitating central vestibular compensation due to antagonism with H3-histamine receptors.
Recovery time after vestibular neurectomy in humans also decreases.

Excitation of neurons in the vestibular nuclei:
Dozavisimo reduces the generation of action potentials in the neurons of the lateral and medial vestibular nuclei.
Pharmacodynamic properties detected in animals provide a positive therapeutic effect of betahistine in the vestibular system.
The effectiveness of betahistine was demonstrated in patients with vestibular dizziness and Meniere's syndrome, which was manifested by a decrease in the severity and frequency of vertigo.

Pharmacokinetics

Suction:
When administered orally, betahistine is rapidly and almost completely absorbed in the gastrointestinal tract (GIT). After absorption, the drug is rapidly and almost completely metabolized to form a metabolite of 2-pyridylacetic acid in the blood plasma and urine. The concentration of betahistine in the blood plasma is very low. Thus, pharmacokinetic analyzes are based on measuring the concentration of 2-pyridylacetic acid metabolite.When taking the drug with food, the maximum concentration (Cmax) of the drug in the blood is lower than when taken on an empty stomach. However, the total absorption of betahistine is the same in both cases, which indicates that food intake slows down the absorption of betahistine.

Distribution:

The binding of betahistine to plasma proteins is less than 5%.

Biotransformation:
After absorption, betahistine is rapidly and almost completely metabolized to form the 2-pyridylacetic acid metabolite (which does not possess pharmacological activity).
The maximum concentration of 2-pyridylacetic acid in plasma (or urine) is reached one hour after ingestion. The half-life is approximately 3.5 hours.

Excretion:
2-peridylacetic acid is rapidly excreted in the urine. When taking the drug in a dose of 8-48 mg, about 85% of the initial dose is found in the urine. Removal of betahistine by the kidneys or through the intestines slightly.

Linearity:
The rate of excretion remains constant when administered orally with 8-48 mg of the drug, indicating the linearity of betahistine pharmacokinetics, and suggests that the metabolic pathway involved is unsaturated.

Indications for use

Treatment of Meniere's syndrome, characterized by dizziness (accompanied by nausea and vomiting), hearing loss and tinnitus.
Symptomatic treatment of vestibular vertigo (vertigo).

Contraindications

Hypersensitivity, pregnancy, breastfeeding, child age.
Hypersensitivity to any of the components of the drug.
Children under 18 years (due to lack of data).
The drug should not be taken in patients with lactose intolerance. Lactase deficiency, glucose-galactose malabsorption syndrome (the drug contains lactose).
Pheochromocytoma.

Carefully

Peptic ulcer or 12 duodenal ulcer (in history), bronchial asthma, urticaria, exanthema, allergic rhinitis, arterial hypotension, while taking antihistamines.

Pregnancy and breastfeeding period

Not enough data to assess the impact of the drug during pregnancy and breastfeeding. In this regard, it is not recommended reception during pregnancy. At the time of treatment should stop breastfeeding.

Dosing regimen

Inside, while eating.
8 mg tablets: 1-2 pills 3 times a day.
Tablets 16 mg: 1/2 pill 3 times a day.
24 mg tablets: 1 pill 2 times a day.
The maximum daily dose is 48 mg.
The dose and duration of treatment should be selected individually depending on the patient's response to treatment.
Improvement is usually noted already at the beginning of therapy, but it can be gradual and manifest even after several weeks of treatment. A stable therapeutic effect in some cases is achieved after several months of treatment.
Dose adjustment in elderly patients, as well as in patients with renal and / or liver failure is not required.

special instructions

The therapeutic effect in some cases increases within several months from the start of treatment.

Overdose

Symptoms: nausea, abdominal pain, drowsiness (when taken in a dose of up to 640 mg); convulsions, cardiopulmonary complications (when taken in a dose of more than 640 mg or in combination with other drugs).
Treatment: symptomatic.

Side effect

Nervous system disorders:
often (from ≥1 / 100 to <1/10) headache, weakness, fatigue, dizziness, lethargy, drowsiness, insomnia.

From the digestive system:
often (≥1 / 100 to <1/10) nausea, dyspepsia (vomiting, abdominal pain, bloating, diarrhea). As a rule, these effects disappear if you take the drug simultaneously with food or after reducing the dose.
In addition to these effects identified during clinical trials, the following side effects were reported in the process of post-marketing use and in the scientific literature (the available data are insufficient to estimate their frequency).

Allergic reactions:
hypersensitivity, incl. Anaphylactic reactions, angioedema.

From the skin:
urticaria, itching, skin rash, redness.

Interaction with other drugs

Antihistamines reduce the activity of betahistine. When used simultaneously with the H1-histamine receptor blockers, the therapeutic effect of betahistine may be reduced.
Cases of interaction or incompatibility with other drugs are unknown.
Based on in vitro data, it can be assumed that there is no inhibition of the activity of cytochrome P450 isoenzymes in vivo.
In vitro data showed inhibition of betahistine metabolism under the action of drugs that inhibit monoamine oxidase (MAO), including MAO subtype B (for example, selegiline). Caution should be exercised while the appointment of betahistine and MAO inhibitors (including MAO-B).

Influence on ability to drive vehicles and work with mechanisms

It does not have a sedative effect and does not affect the ability to drive vehicles or work on machines and mechanisms.

Storage conditions

Store in a dry, dark place at temperatures not higher than 25 ° C.
Keep out of reach of children.