Betagistin

General characteristics. Structure:

Active ingredient: 8 mg, 16 mg or 24 mg of a betagistin of dihydrochloride in 1 tablet.

Excipients: lactoses monohydrate, cellulose microcrystallic, magnesium stearate, silicon dioxide colloid, starch corn.

Pharmacological properties:

Pharmacodynamics. The mechanism of action of a betagistin is known only partially. There are several possible hypotheses confirmed with preclinical and clinical data:

Influence on gistaminergichesky system: The partial antagonist of H1 - histamine the antagonist of H3 - histamine receptors of vestibular nuclei of the central nervous system (CNS), has insignificant activity concerning H2 receptors. Betagistin increases exchange of a histamine and its release by blocking presynaptic H3 receptors and decrease in quantity of H3 receptors.

Strengthening of a blood-groove of cochlear area, and also all brain: According to preclinical trials бетагистин improves blood circulation in a vascular stripe of an inner ear due to relaxation of irskapillyarny sphincters of vessels of an inner ear. It is also shown what бетагистин strengthens a brain blood stream at the person.

Simplification of process of the central vestibular kopensation. Betagistin accelerates recovery of vestibular function at animals after a unilateral vestibular neurectomy, accelerating and facilitating the central vestibular compensation for the account of antagonism with H3 - histamine receptors.

Recovery time after a vestibular neurectomy at the person also decreases. Excitement of neurons in vestibular nuclei. Dozozavisimo reduces generation of action potentials in neurons of lateral and medial vestibular nuclei.

The Pharmakodinamicheksy properties revealed on animals provide positive therapeutic effect of a betagistin in vestibular system.
Efficiency of a betagistin was shown at patients with vestibular dizziness and Menyer's syndrome that was shown by reduction of expressiveness and frequency of dizzinesses.

Pharmacokinetics. Absorption. At oral administration бетагистин it is quickly and almost completely soaked up in the digestive tract (DT). After absorption drug is quickly and almost completely metabolized with formation of a metabolite of 2-pyridylacetic acid in a blood plasma and urine. Concentration of a betagistin in a blood plasma very low. Thus, pharmacokinetic analyses are based on measurement of concentration of a metabolite of 2-pyridylacetic acid. At administration of drug with food the maximum concentration (Cmax) of drug in blood is lower, than at reception on an empty stomach. However total absorption of a betagistin is identical in both cases that it uazyvat on the fact that meal slows down absorption of a betagistin.

Raspredleniye. Linkng of a betagistin with proteins of a blood plasma makes less than 5%.

Biotransformation. After absorption бетагистин quickly and almost it is completely metabolized with formation of a metabolite of 2-pyridylacetic acid (which has no pharmacological activity).

The maximum concentration of 2-pyridylacetic acid in a blood plasma (or urine) is reached in an hour after reception. Elimination half-life about 3,5 hours.

Removal. 2-peridiluksusny acid is quickly removed with urine. At administration of drug in a dose of 8-48 mg about 85% of an initial dose are found in urine. Removal of a betagistin kidneys or through intestines slightly.

Linearity. Speed of removal remains to a constant at oral administration of 8-48 mg of drug, indicating linearity of pharmacokinetics of a betagistin, and allows to assume that the involved metabolic way remains unsaturated.

Indications to use:

The treatment of a syndrome of Menyer who is characterized by dizziness (which is followed by nausea and vomiting), decrease in hearing and a sonitus. Symptomatic treatment of vestibular dizziness (вертиго).

Route of administration and doses:

Inside, during food.

Tablets of 8 mg: on 1-2 tablets 3 times a day.
Tablets of 16 mg: on 1/2 tablets 3 times a day.
Tablets of 24 mg: on 1 tablet 2 times a day.

The maximum daily dose – 48 mg. The dose and duration of treatment should be selected individually depending on reaction of the patient to treatment.

Improvement is usually noted already at the beginning of therapy, but it can be and gradual and be shown even in several weeks of treatment. The stable therapeutic effect is in certain cases reached several months of treatment later.

Dose adjustment at patients of advanced age, and also with a renal and/or liver failure is not required from patients.

Features of use:

Pregnancy and period of breastfeeding. There are not enough data for assessment of influence of drug during pregnancy and breastfeeding. In this regard reception at pregnancy is not recommended. For the period of treatment it is necessary to stop breastfeeding.

The therapeutic effect in some cases increases within several months from an initiation of treatment.

Influence on ability of control of motor transport and work with mechanisms. Does not possess sedation and does not influence ability to manage motor transport or to work at machines and mechanisms.

Side effects:

Disturbances from a nervous system: often (from ≥1/100 to <1/10) a headache, weakness, fatigue, dizziness, slackness, drowsiness, sleeplessness.

From the alimentary system: often (from ≥1/100 to <1/10) nausea, dyspepsia (vomiting, an abdominal pain, abdominal distention, diarrhea). As a rule, these effects disappear if to accept drug along with food or after a dose decline.

Except these effects revealed at conduct of clinical trials in the course of post-marketing use and in scientific literature it was reported about the following side effects (the available data are not enough to estimate their frequency).

Allergic reactions: hypersensitivity, including anaphylactic reactions, Quincke's disease.

From integuments: urticaria, itch, skin rash, reddening.

Interaction with other medicines:

Antihistamines reduce activity of a betagistin. At simultaneous use with blockers of H1-histamine receptors the therapeutic effect of a betagistin can decrease.

Cases of interaction or incompatibility with other medicines are unknown.

Based on these in vitro, it is possible to assume absence inhibition of activity of isoenzymes of in vivo P450 cytochrome.

These in vitro showed inhibition of metabolism of a betagistin under the influence of drugs which inhibit monoamine oxidase (MAO), including subtype B MAO (for example, селегилин).

It is necessary to be careful at co-administration of a betagistin and MAO inhibitors (including MAO-B).

Contraindications:

• Hypersensitivity, pregnancy, breastfeeding period, children's age.
• Hypersensitivity to any of drug components.
• Children up to 18 years (due to the lack of data).
• Drug should not be accepted to patients with a lactose intolerance.
• Deficit of lactase, syndrome of glyukozo-galaktozny malabsorption (drug contains lactose).
• Pheochromocytoma.

With care. A peptic ulcer of a stomach or a 12-perstny gut (in the anamnesis), bronchial asthma, a small tortoiseshell, a dieback, allergic rhinitis, arterial hypotension, at reception of antihistaminic drugs.

Overdose:

Symptoms: nausea, abdominal pain, drowsiness (at reception in a dose to 640 mg); spasms, cardiopulmonary complications (at reception in a dose more than 640 mg or in combination with other medicines).

Treatment: symptomatic.

Storage conditions:

List B. To store in the dry, protected from light place at a temperature not above 25 °C. To store in the place, unavailable to children. Not to apply after the date specified on packaging. A period of validity - 3 years.

Issue conditions:

Without recipe

Packaging:

Tablets on 8 mg, 16 mg, 24 mg. On 7 tablets in a blister strip packaging. 2, 3, 4 blister strip packagings together with the application instruction are placed in a pack from a cardboard. On 10 tablets in a blister strip packaging. 1, 2, 3, 4, 5 blister strip packagings