Antileukotriene drugs represent a new class of drugs that reduce inflammatory processes that have an infectious or allergic etiology.
In order to understand the principle of action of such drugs, it is worth understanding what leukotrienes are.
Leukotrienes
They are mediators of inflammatory processes. In their chemical structure, they are fatty acids that are formed by arachidonic acid.
Leukotrienes are involved in the development of bronchial asthma. Like histamine, they are a mediator of immediate allergic reactions. Histamine can cause a rapid, but short-term spasm of the bronchi, and leukotrienes cause a delayed and longer spasm.
How are antileukotriene drugs classified?
The following leukotrienes are currently classified: A 4 , B 4 , C 4 , D 4 , E 4 .
The synthesis of leukotrienes comes from arachidonic acid. It under the influence of 5-lipoxygenase passes into leukotriene A 4 . After this, a cascade reaction occurs, as a result of which the following B 4 -C 4 -D 4 -E 4 leukotrienes are formed. The end product of this reaction is LTE 4 .
It was found that LTE 4 , D 4 , E 4 are able to cause a bronchoconstrictor effect, increase mucus secretion, can contribute to the development of swelling, inhibit mucociliary clearance.
B 4 , D 4 , E 4 have chemotactic activity, that is, they can attract neutrophils and eosinophils to the area of โโthe inflammatory process.
Scientists have proved that leukotrienes are produced by macrophages, mast cells, eosinophils, neutrophils, T-lymphocytes, which are directly involved in an inflammatory reaction. Antileukotriene preparations for bronchial asthma are often used.
After the cells have come into contact with the allergen and the airways have cooled, or after exercise, RT synthesis is activated. That is, the synthesis begins when the osmolarity of the bronchial contents increases.
Four groups of drugs
Currently, only four groups of antileukotriene drugs are known:
- "Zileuton", which is a direct inhibitor of 5-lipoxygenase.
- Drugs that are FLAP inhibitors that prevent the process of binding this protein to arachidonic acid.
- "Zafirlukast", "Pobilukast", "Montelukast", "Pranlukast", "Verlukast", which are antagonists of sulfide peptide leukotriene receptors.
- Drugs that are antagonists of Leukotriene B 4 receptors.
The most studied are antileukotriene drugs of the first group and funds of the third group. Consider the representatives of these groups in more detail.
Zileuton
Zileuton is a reversible 5-lipoxygenase inhibitor. It is able to inhibit the formation of sulfide peptide RT and LT B 4 . The drug can have a bronchodilator effect lasting up to five hours. He is also able to prevent the occurrence of bronchial spasm, which is a consequence of exposure to cold air or "Aspirin".
Numerous studies prove that Zileuton, prescribed to patients suffering from bronchial asthma for one to six months, can reduce the patient's need for inhalation of ฮฒ2-adrenergic agonists and glucocorticoids. A single dose of "Zileuton" prevents the occurrence of sneezing and difficulty in nasal breathing in those patients who suffer from allergic rhinitis after nasal administration of the allergen.
Six-week therapy with the use of "Zileuton" in patients with atopic asthma showed a significant result. Doctors note a qualitative decrease in the level of eosinophils and neutrophils. The tumor necrosis factor in the lavage fluid of the bronchoalveolar type also decreased after the allergen test. That is why antileukotriene preparations are unique, the mechanism of action is based on this.
โZileutonโ is characterized by a rather short period during which its half-life occurs. This suggests that the drug should be taken often enough, up to four times a day. In addition, Zileuton is able to lower theophylline clearance. This must be taken into account if you are supposed to take theophylline and Zileuton in parallel. That is, the dose of the first should be reduced. If Zileuton is prescribed for a long period, then the level of liver enzymes should be monitored.
But there are new generation antileukotriene drugs, a list of them is presented below.
Agents that are antagonists of sulfide peptide leukotrienes are highly selective competitors and reversible blockers of LT D 4 receptors. Such drugs include Pranlukast, Zafirlukast, Montelukast.
"Akolat" ("Zafirlukast")
"Zafirlukast", aka "Akolat", is the most studied drug in this group of antileukotriene substances. He also has activity bronchodilator orientation. The effect lasts quite a long time, up to five hours. Zafirlukast is able to prevent the development of an asthmatic reaction in case of allergen inhalation. Its effectiveness has been proven in the prevention of bronchospasm, which is provoked by cold air, aspirin, exercise, pollutants. This drug, as well as the Montelukast drug, can enhance the bronchodilator activity of ฮฒ2-adrenergic agonists.
"Akolat" ("Zafirlukast") has good absorption, the peak of its concentration in the blood is reached after three hours after its administration. Its half-life is slightly longer than that of Zileuton, and is 10 hours. In addition, it does not affect the clearance of theophylline. This drug should be taken either an hour before a meal, or after two hours after it, since food significantly reduces its absorption capacity. The product is well tolerated by patients.
Conclusion
Anti-leukotriene drugs for allergies can be used for children, but not earlier than they reach the age of two. With the help of these medicines, children are treated with recurrent bronchitis, allergic rhinitis, and mild bronchial asthma.