Anti-histamines are a group of substances that can prevent or suppress the action of histamine. In addition to phenothiazine derivatives, diprazine (see), etizine (see), anti- histamine agents include substances of various chemical structures — diphenhydramine (see), diazolin (see), suprastin.
Anti-histamine drugs prevent histamine-induced spasms of the muscles of the bronchi and intestines, reduce the hypotensive effect of histamine, reduce the capillary permeability and prevent the development of tissue edema under the influence of histamine. Anti-histamines do not prevent the increased secretion of gastric juice caused by histamine.
In addition to antihistamine activity, a number of antihistamine agents (diprazin, etizin and diphenhydramine) cause a sedative and hypnotic effect, has antiemetic activity.
Anti-histamine drugs are used for allergic conditions (urticaria, hay fever , vasomotor rhinitis , allergic conjunctivitis, angioedema, professional dermatitis, eczema , capillary toxicosis), as well as for drug allergies, radiation sickness, and to reduce heart disease, and in order to reduce heart failure, and in order to reduce heart failure, and in order to reduce heart failure, and to relieve heart failure, and in order to alleviate allergic reactions. Anti-histamine drugs with sedative properties are effective for sea and air sickness , Meniere's syndrome. Anti-histamine drugs that have a depressant effect on the central nervous system should not be prescribed while working for transport drivers and other people whose profession requires a quick mental and motor response.Go
Antihistamines (antihistamines) - a group of substances that can suppress the action of histamine on individual organs and the whole organism. Antihistamines prevent histamine-induced spasm of the muscles of the bronchi and intestines, reduce its effect on blood circulation, prevent an increase in capillary permeability that occurs when histamine is administered, and facilitate the course of anaphylactic reactions. Antihistamines do not prevent histamine-induced hypersecretion of gastric juice; do not have a significant effect on the formation and release of histamine and do not violate the antigen – antibody reaction. Most likely, their anti-histamine activity is explained by the competitive relationship with histamine and the blocking of histaminergic receptors of smooth muscle cells and glands.
The pharmacological action of antihistamines is not limited to antihistamine properties.
They also have other types of pharmacological activity [choline and adrenolytic activity, antispasmodic (myotropic) action and anesthetic properties], which in some cases expands the possibility of their therapeutic use. Many antihistamines have a depressant effect on the central nervous system, cause a sedative and hypnotic effect, increase the effect of narcotic, analgesic and anesthetics, prevent nausea and vomiting in sea and air sickness, soothe vomiting in pregnant women, have anticonvulsant activity. These properties are most pronounced in phenothiazine derivatives (see Diprazin, Etizin), to a somewhat lesser extent - in Dimedrol (see) and much weaker - in suprastin. Some antihistamines, such as diazolin (see), have no inhibitory effect on the central nervous system.
Antihistamines are used mainly in allergic conditions: urticaria, hay fever, allergic and vasomotor rhinitis, allergic conjunctivitis, angioedema, medicinal allergies, occupational dermatitis, eczema, kapillyarotoksikoz, Meniere's disease, in an initial stage of asthma to reduce reactions during blood transfusion and blood replacement fluids. Treatment with antihistamines is symptomatic and is carried out before the onset of spontaneous or artificial desensitization. A number of antihistamines (diphenhydramine, diprazin) can be used to prevent sea and air sickness as sedatives, as well as in the treatment of parkinsonism, chorea, vomiting of pregnant women, radiation sickness, to eliminate vestibular disorders.
Antihistamines are well absorbed both by parenteral administration and by ingestion. Duration of effect from 3-6 hours. (Diprazin, Dimedrol, Suprastin) up to 1-2 days.
Antihistamines are usually administered orally in doses of 0.025-0.05 g and in injections (under the skin, intramuscularly and intravenously) - 0.025 g each. With skin manifestations of allergy, antihistamines can also be used topically in the form of lotions. Antihistamines are low toxic and usually well tolerated, but they can cause dizziness in some individuals. There are cases of skin sensitization to the corresponding antihistamines. With prolonged use may develop leukopenia. Due to the presence of a local irritant effect in a number of antihistamines, when they are injected under the skin, infiltrates sometimes occur. When prescribing antihistamines, it is necessary to take into account the side properties inherent to certain members of this group (inhibitory effect on the central nervous system, anticholinergic activity, etc.). For liver and kidney disease, antihistamines should be used with caution.