Translation of the instructions can be
MAXGISTIN tablets 8 mg, tablets 16 mg, tablets 24 mg
Instruction
For medical use of the medicinal product
Maxhistine
(Maxgistin)
Composition:
Active ingredient: betahistine dihydrochloride;
1 tablet contains betahistine dihydrochloride 8 mg or 16 mg or 24 mg;
excipients: microcrystalline cellulose, mannitol (E 421), citric acid monohydrate, colloidal anhydrous silicon dioxide, talc.
Dosage form.
Pills.
Main physicochemical properties:
8 mg tablets: white or almost white, round tablets, without a dividing risk;
16 mg tablets: white or almost white, round tablets with a dividing line;
24 mg tablets: white or almost white, round tablets, without a dividing risk.
Pharmacotherapeutic group.
Treatments for vestibular disorders.
PBX code N07C A01.
Pharmacological properties.
Pharmacodynamics.
The mechanism of action of betahistine is only partially understood. There are several plausible hypotheses for its mechanism of action.
The effect of betahistine on the histaminergic system: it has been established that betahistine partially exhibits agonistic activity towards H 1 receptors, as well as antagonistic activity towards H 3 histamine receptors in nervous tissue and has insignificant activity towards H 2 histamine receptors. Betahistine increases the metabolism and release of histamine by blocking presynaptic H 3 receptors and inducing the process of reducing the number of corresponding H 3 receptors.
Betahistine may increase blood flow to the cochlear area, as well as to the entire brain: betahistine improves blood flow in the stria vascularis of the inner ear, probably by relaxing precapillary sphincters in the inner ear microcirculation system. Betahistine has also been shown to increase cerebral blood flow in humans.
Betahistine promotes vestibular compensation: betahistine accelerates the recovery of vestibular function after unilateral neurectomy by stimulating and promoting the process of central vestibular compensation. This effect is characterized by increased regulation of histamine metabolism and release and is realized as a result of H 3 -receptor antagonism. In humans, the time to recovery of vestibular function after neurectomy was also reduced during treatment with betahistine.
Betahistine alters the activity of neurons in the vestibular nuclei: betahistine has a dose-dependent inhibitory effect on the generation of spike potentials in neurons of the lateral and medial vestibular nuclei.
The pharmacodynamic properties of betahistine can provide a positive therapeutic effect of the drug in the vestibular system.
The effectiveness of betahistine has been shown in studies in patients with vestibular vertigo and Ménière's disease, as demonstrated by a reduction in the severity and frequency of vertigo attacks.
Pharmacokinetics.
absorption
When administered orally, betahistine is rapidly and almost completely absorbed from all parts of the digestive tract. After absorption, the drug is rapidly and almost completely metabolized to form the metabolite 2-pyridylacetic acid. The concentration of betahistine in the blood plasma is very low. Therefore, all pharmacokinetic analyses are carried out by measuring the concentration of the metabolite 2-pyridylacetic acid in plasma and urine.
When the drug is taken with food, the maximum concentration of the drug is lower than when taken on an empty stomach. At the same time, the complete absorption of betahistine is identical in both cases, indicating that food intake only slows down the absorption process of the drug.
distribution
The percentage of betahistine that binds to blood plasma proteins is less than 5%.
Biotransformation
After absorption, betahistine is rapidly and almost completely metabolized to 2-pyridylacetic acid (which does not exhibit pharmacological activity).
After oral administration of betahistine, the concentration of 2-pyridylacetic acid in blood plasma (and urine) reaches its maximum 1 hour after administration and decreases with a half-life of about 3.5 hours.
breeding
2-pyridylacetic acid is rapidly excreted in the urine. When taking the drug in a dosage of 8-48 mg, about 85% of the initial dose is found in the urine. The excretion of betahistine by the kidneys or with feces is insignificant.
linearity
The recovery rate remains constant with oral administration of 8-48 mg of the drug, indicating linearity of the pharmacokinetics of betahistine, and suggesting that the metabolic pathway involved is unsaturated.
Clinical characteristics.
Indication.
Meniere's disease and syndrome, which are characterized by three main symptoms:
dizziness, sometimes accompanied by nausea and vomiting; hearing loss (deafness); tinnitus.
Symptomatic treatment of vestibular vertigo of various origins.
Contraindication.
Hypersensitivity to any of the components of the drug.
Pheochromocytoma.
Interaction with other drugs and other types of interactions.
In vitro data indicate inhibition of betahistine metabolism by drugs that inhibit monoamine oxidase (MAO) activity, including MAO subtype B (e.g. selegiline). Caution is recommended when betahistine is used concomitantly with MAO inhibitors (including selective MAO subtype B).
Since betahistine is a histamine analogue, the interaction of betahistine with antihistamines could theoretically affect the effectiveness of one of these drugs.
Application features.
During treatment with the drug, it is necessary to carefully monitor the condition of patients with bronchial asthma and/or a history of gastric and duodenal ulcers.
Use during pregnancy or breastfeeding.
Pregnancy.
There are no adequate data on the use of betahistine in pregnant women, so the drug should not be prescribed during this period, except in cases of absolute necessity.
Breastfeeding period.
It is not known whether betahistine is excreted in human milk. The benefit of the drug to the mother should be weighed against the benefits of breastfeeding and the potential risk to the child.
The ability to influence the reaction speed when driving vehicles or other mechanisms.
Betahistine is indicated for the treatment of Ménière's syndrome, which is characterized by a triad of main symptoms: dizziness, hearing loss, tinnitus, and for the symptomatic treatment of vestibular vertigo. Both conditions may adversely affect the ability to drive and use machines. According to clinical studies that have studied the effects on the ability to drive and use machines, betahistine had no or negligible effect on this ability.
Method of administration and doses.
The daily dose for adults is 24-48 mg, evenly distributed throughout the day.
| 8 mg tablets | 16 mg tablets | 24 mg tablets |
| 1-2 tablets 3 times a day | ½-1 tablet 3 times a day | 1 tablet 2 times a day |
It is advisable to take the tablets after meals. The dose should be selected individually depending on the effect. A reduction in symptoms is sometimes observed only after 2-3 weeks of treatment. The best results are sometimes achieved when taking the drug for several months. There is evidence that prescribing treatment at the beginning of the disease prevents its progression and / or hearing loss in the later stages.
Elderly patients
Although currently there are limited data from studies in this patient group, extensive experience with the drug in the post-marketing period suggests that dose adjustment is not required in this patient population.
Kidney failure
No specific studies have been conducted in this patient group, but based on post-marketing experience, no dose adjustment is required.
liver failure
No specific studies have been conducted in this patient group, but based on post-marketing experience, no dose adjustment is required.
Children.
Since there is insufficient data on the safety and efficacy of betahistine in children, the drug is not recommended for use in this category of patients.
Overdose.
Several cases of overdose of the drug are known. Some patients experienced mild to moderate symptoms (nausea, drowsiness, abdominal pain) after taking the drug in doses up to 640 mg. More serious complications (convulsions, cardiopulmonary complications) were observed with intentional administration of increased doses of betahistine, especially in combination with an overdose of other drugs.
Treatment: symptomatic and supportive therapy.
Adverse reactions.
Gastrointestinal tract: nausea and dyspepsia, complaints of minor stomach upset (vomiting, gastrointestinal pain, bloating and flatulence). These side effects usually disappear when the drug is taken with food or after reducing the dose.
From the nervous system: headache.
Immune system disorders: hypersensitivity reactions, e.g. anaphylaxis.
Skin and subcutaneous tissue disorders: Hypersensitivity reactions of the skin and subcutaneous tissue, including angioedema, rash, pruritus and urticaria, have been observed.
Expiration date.
3 years.
Storage conditions.
Store in the original packaging at a temperature not exceeding 25 °C.
Keep out of reach of children.
Packaging.
10 tablets in a blister; 3 blisters in a pack.
Vacation category.
According to the recipe.
Producer.
LLC "Pharmex group".
Location of the manufacturer and address of its place of business.
Ukraine, 08301, Kyiv region, Boryspil city, Shevchenko st., building 100.
