Pharmacological properties
Ketotifen has a membrane-stabilizing, antiallergic, antihistamine effect. The mechanism of action of ketotifen is due to the inhibition of the release of biologically active substances by mast cells and basophilic granulocytes (histamine, leukotrienes, etc.), suppression of eosinophil sensitization by cytokines, blocking their migration to the foci of inflammation. The drug inhibits the development of respiratory tract hyperreactivity caused by platelet activation under the influence of platelet activating factor (PAT) or allergens. The drug inhibits phosphodiesterase, increases the level of cAMP in cells. Ketotifen causes non-competitive blockade of H1-histamine receptors. Effectively prevents bronchospasm, reduces the need for the use of corticosteroids, bronchodilators. It does not have a bronchodilator effect. The therapeutic effect after taking the drug develops slowly, within 1-2 months.
When taken orally, ketotifen is absorbed almost completely. The main metabolite of ketotifen N-gluronide is practically non-toxic. The maximum concentration in the blood plasma is reached after 2-4 hours. Protein binding is about 75%. Ketotifen is eliminated from the body in a two-phase manner: the first half-life is 3-5 hours, the second - 21 hours. Approximately 60-70% of the drug is excreted by the kidneys and 30-20% - by the liver in the form of metabolites, 10% of the drug is excreted unchanged. Within 48 hours, the main part of the taken single dose of the drug is excreted in the urine. The nature of metabolism in children is the same as in adults, but the clearance is higher. Therefore, children over 3 years old need the same daily dose as adults.
Indication
Prevention of asthma attacks, allergic bronchitis, asthmatic complications of hay fever, allergic dermatoses, allergic rhinitis and conjunctivitis, urticaria.
Application
Adults and children over 14 years of age are prescribed 1-2 mg of ketotifen (5-10 ml of syrup) 2 times a day. Children aged 6 months to 3 years are prescribed the drug 2 times a day at 0.0125 mg of ketotifen per 1 kg of body weight. Children over 3 years of age are prescribed the drug 2 times a day at 0.025 mg of ketotifen per 1 kg of body weight. The required dose is measured using a dosing device with a graduation value of 0.1 ml.
Contraindication
Hypersensitivity to the components of the drug, pregnancy and breastfeeding, age up to 6 months.
Side effects
Possible drowsiness, dry mouth, mild dizziness, slowed mental reactions, usually disappear after a few days of taking. Sometimes dyspeptic disorders, thrombocytopenia, dysuria, cystitis are noted. In rare cases, weight gain due to increased appetite.
Special instructions
Patients taking ketotifen should refrain from potentially hazardous activities that require increased attention. At the beginning of treatment with ketotifen, anti-asthma drugs, especially systemic corticosteroids, should not be abruptly discontinued due to the possible development of adrenal insufficiency.
Alcohol should be avoided while using the drug.
Interactions
When taken simultaneously, it enhances the effect of hypnotics, antihistamines, and alcohol. When taking ketotifen, the need for corticosteroids and bronchodilators in patients with BA may decrease. In combination with antidiabetic drugs, it increases the likelihood of developing thrombocytopenia.
Overdose
It is characterized by drowsiness, confusion, disorientation, tachycardia, arterial hypotension, increased excitability, convulsions (especially in children), coma. In case of overdose, it is recommended to prescribe emetics, gastric lavage, prescribe activated charcoal, saline laxatives; if necessary, symptomatic treatment is carried out, the state of the cardiovascular system is monitored, and short-acting barbiturates or benzodiazepines are prescribed for agitation or convulsions.
Storage conditions
In a dry, dark place at a temperature of 15-25 ° C. Shelf life - 3 years.
