Antihistamines - pharmacologicala group of medicinal substances that suppress the activity of specific histamine receptors in the cells of the body. The effect of these drugs is to eliminate spasm of smooth muscles of the intestine and bronchi, reduce the permeability of capillaries, alleviate the course of reactions of the allergic type, prevent the tissue edema.
Antihistamines are in most cases available without a prescription. Such drugs include "Brompheniramine", "Chlorpheniramine", "Clemastin", "Dimedrol", "Loratadin".
Prescription drugs: "Cetirizine", "Desloratadine", "Focsofenadine". These drugs almost do not cause side effects, which are manifested by dry mouth or drowsiness.
Antihistamines are classified into threegroup, according to their structure: ethylenediamines, ethanolamines, alkylamines, piperazines, tricyclics. The first, the second type of medicinal substances causes a characteristic side effect - drowsiness, which somewhat limits their use. To eliminate this drawback, alkylamines have been developed. They are used to relieve the symptoms of colds: lacrimation, sneezing, cold. The purpose of using piperazines is to influence the areas of the brain responsible for the occurrence of a feeling of motion sickness, dizziness, nausea, vomiting. Antihistamines for pregnant women are tricyclics. They are used for the treatment of toxicoses, a sedative effect. All the data of a group of medicinal substances in medical practice are combined into first-generation drugs.
Today a significant number ofexperiments and drug testing. On the basis of these, two new generations of antihistamines were isolated. They differ in chemical composition and in the number of side effects. Antihistamines of the third generation operate only on target organs, do not affect other body systems. They were developed to treat Alzheimer's disease.
The mechanism of action of the drugs givenThe pharmacological group consists in the displacement of histamine from the tissue systems, the blockage of glandular cell receptors and smooth muscle. As a result, an obstacle is created for the onset of allergy symptoms. Drugs are the most effective in the case of continuous reception.
Contraindications for antihistaminesis hypersensitivity to their active substances. There are undesirable effects in cases of taking and monoxidase inhibitors. Patients with glaucoma and nursing mothers are also undesirable to use these medications (before the use of mandatory medical advice). Currently, antihistamines for infants have been developed, which are similar in composition to those of the third generation. They cause minimal side effects and do not affect the metabolic processes of the body.
Drugs antihistamine series are available in the form of liquid, tablets, capsules. The frequency of admission directly depends on their type and characteristics.
Medicinal substances can not be combined withdrugs that have a sedative effect, since they greatly enhance it. These drugs include tranquilizers. It is not recommended to combine antihistamines with monooxidase inhibitors, phaseline sulfate, trannicyl quipromil.
Specific side effects of substances in this group are dry mouth, drowsiness, delayed urination, loss of visual acuity.</ p>>