Antihistamines for systemic use.
Ketotifen belongs to the group of cycloheptothiophenones and has a pronounced antihistamine effect. It belongs to the group of non-bronchodilating anti-asthma preparations. The mechanism of its action is associated with inhibition of the release of histamine and other mediators of mastatsytam, with blocking of histamine H1 receptors and inhibition of the phosphodiesterase enzyme, as a result of which the level of cAMP in mast cells increases. Suppresses the effects of TAF (platelet-activating factor). When used alone, it does not stop attacks of bronchial asthma, but prevents their occurrence and leads to a reduction in their duration and intensity, while in some cases they completely disappear.
It is almost completely absorbed from the digestive tract. The maximum plasma level is reached in 2-4 hours. The equilibrium state is achieved after taking the minimum daily dose, which is 2 mg. Binds to blood plasma proteins by about 75%. The volume of distribution is 2.7 l / kg.
About 60% of the dose taken is metabolized in the liver in three ways (demethylation, N-oxidation, N-glucuroconjugation) to the following metabolites: ketotifen-N-glucuronide (pharmacologically inactive), norketotifen (with pharmacological activity similar to that of unchanged ketotifen), N-oxide ketotifen and
10-hydroxyketotifen (with unknown pharmacological activity).
It is excreted biphasically, with a short half-life of 3 to 5 hours and a longer period of 21 hours. About 1% is excreted unchanged in the urine within 48 hours, 60–70% - in the form of metabolites.
Preventive treatment of bronchial asthma, especially atopic asthma.
Symptomatic treatment of allergic conditions, including allergic rhinitis and conjunctivitis.
Hypersensitivity to ketotifen or to other components of the preparation.
Avoid the simultaneous use of ketotifen and oral antidiabetic agents (risk of developing reversible thrombocytopenia) until this phenomenon is sufficiently understood.
1 tablet contains ketotifen (in the form of ketotifen hydrofumarate) - 1 mg (0.001 g);
excipients: lactose monohydrate, microcrystalline cellulose, magnesium stearate, colloidal anhydrous silicon dioxide, talc.
With the simultaneous use of ketotifen and oral antidiabetic agents, there is a risk of reversible thrombocytopenia, therefore, this combination of preparations should be avoided.
With the simultaneous use of atropine, agents with atropine-like action and ketotifen, the risk of side effects, such as urinary retention, constipation, and dry mouth, increases.
Ketotifen can potentiate the effects of other preparations that depress the central nervous system (sedatives, hypnotics). The simultaneous use of ketotifen with other antihistamines can lead to the mutual potentiation of their effects. Ethanol enhances the depressive effect of ketotifen on the central nervous system.
The preparation is ineffective in the treatment of acute allergic reactions and asthma attacks. the maximum therapeutic effect of the preparation occurs after several weeks of systematic administration.
The normalization of the function of the pituitary-adrenal system can last up to 1 year. Therefore, in the first weeks of using ketotifen, it is recommended to continue the previous treatment and cancel it gradually and for a long time.
At the beginning of long-term treatment with ketotifen, you should not suddenly stop treatment with other anti-asthma preparations, especially corticosteroids. In patients with steroid dependence, adrenocortical insufficiency may develop.
In the case of intercurrent infection, it is necessary to carry out specific anti-infective therapy.
When treating with the preparation, it is necessary to be under the supervision of a physician, given the possibility of seizures.
Ketotifen should be carefully prescribed to patients with a history of epilepsy due to the possibility of lowering the seizure threshold during preparation treatment.
Alcohol should not be consumed during treatment with ketotifen, as it enhances the depressive effect of ketotifen on the central nervous system.
You should stop taking the preparation 10-14 days before the skin tests to determine the allergy.
If it is necessary to stop treatment with Ketotifen, the dose is gradually reduced over 2-4 weeks to prevent recurrence of asthma symptoms.
Caution should be exercised when using ketotifen in patients with impaired liver function.
Given that concomitant use with oral hypoglycemic preparations can cause thrombocytopenia, such a combination of preparations should be avoided or platelet counts should be carefully monitored if such treatment is recommended.
The preparation contains lactose, so it should not be prescribed to patients with rare hereditary forms of galactose intolerance, lactase deficiency or glucose-galactose malabsorption syndrome.
Application during pregnancy or lactation.
Since controlled clinical trials in pregnant women have not been conducted, the use of the preparation ketotifen is possible only when the expected benefit to the mother outweighs the potential risk to the fetus.
Ketotifen passes into breast milk, so women should stop breastfeeding if it is necessary to use the preparation.
The ability to influence the reaction rate when driving vehicles or other mechanisms.
At the beginning of treatment, the preparation ketotifen can slow down the rate of reactions, which requires the patient to be extremely careful when driving and working with automated mechanisms.
Method of administration and dosage.
The tablets are taken orally during meals with water.
Dosage.
Adults: 1 tablet (1 mg) 2 times a day, morning and evening with meals. Patients who experience a significant sedative effect that occurs in the first days of using the preparation should take Ketotifen 1 tablet per day only in the evening.
If necessary, the daily dose can be increased to 4 mg, that is, 2 tablets 2 times a day. When using a higher dose, an early onset of a therapeutic effect can be expected.
Children from 3 years old: 1 tablet (1 mg) 2 times a day, morning and evening, with meals.
Elderly patients: there are no specific recommendations for elderly patients.
Duration of treatment.
The treatment is long-term, while the therapeutic effect is achieved after several weeks of therapy. Treatment should be continued for at least 2-3 months, especially in patients who did not feel better in the first weeks.
Concomitant bronchodilator therapy: Concomitant use of ketotifen with bronchodilators may reduce the frequency of bronchodilator use.
Termination of therapy.
Discontinue treatment with ketotifen gradually, over 2–4 weeks, to avoid the risk of relapse of asthmatic symptoms.
Children.
For use in children from 3 years of age.
For children under 3 years of age, the preparation should be prescribed in a different dosage form.
Overdose.
Symptoms: possible significant disturbances in the psychomotor reaction, drowsiness before severe sedation, headache, disorientation, tachycardia, decreased blood pressure, coma (especially in children), symptoms of nervous system excitation, including seizures.
Bradycardia, arrhythmia, depression of the respiratory center, and nystagmus are also observed. In the event of the above symptoms, the patient should be carefully examined.
Treatment: general measures to eliminate the unresorbed amount of the preparation in the digestive tract: induce vomiting, rinse the stomach. The use of activated carbon can have beneficial effects. If necessary, symptomatic treatment and monitoring of the cardiovascular and respiratory systems are recommended. In states of arousal, short-acting barbiturates or benzodiazepines can be used.
Adverse reactions.
Infections and invasions: cystitis.
From the immune system: skin rashes, severe skin reactions, erythema multiforme, Stevens-Johnson syndrome.
Metabolic disorders: weight gain due to increased appetite.
Mental disorders: psychomotor agitation, irritability, insomnia, anxiety, nervousness, disorientation, drowsiness.
From the nervous system: dizziness, sedation, convulsions.
From the digestive tract: dry mouth, stomach pain, constipation, nausea, vomiting, dyspeptic disorders.
From the hepatobiliary system: increased levels of liver enzymes, hepatitis.
From the urinary system: dysuria.
Dry mouth and dizziness may appear early on in treatment, but these usually resolve spontaneously with treatment. CNS stimulation symptoms such as agitation, irritability, insomnia, and anxiety are rare, especially in children.
Shelf life.
5 years.
Storage conditions.
Keep out of the reach of children in the original packaging at a temperature not exceeding 25 ° C.