Antihistaminic Drugs

Antihistaminic Drugs

 

a group of substances capable of suppressing the action of free histamine, a biologically active substance occurring in cells and tissues. Antihistaminic drugs relieve spasms of the smooth muscles of the bronchi and intestines caused by histamine, decrease capillary permeability, inhibit the development of edema caused by histamine, and relieve allergic reactions.

The mechanism of antihistaminic-drug action is not entirely clear. It is thought that the antihistaminic activity of these drugs is explained by their displacement of histamine from the biochemical tissue systems and by blockage of the receptors of the cells of the smooth muscles and glands. Some data show that antihistaminic drugs increase the activity of histaminase, an enzyme that promotes the decomposition of histamine. Along with antihistaminic action, many antihistaminic drugs have a depressive effect on the central nervous system; cause drowsiness; reinforce the effects of narcotics, somnifacients, analgesics, and local anesthetics; lower body temperature; act as anti-inflammatories and prevent nausea and vomiting in motion sickness; relieve vomiting in pregnancy; and produce other effects. These properties are most strongly evident in diprazin and etisine, to a somewhat lesser degree in dimedrol, and to a considerably weaker degree in suprastin. A few antihistaminic drugs—for example, diazoline—exert no depressive effect on the central nervous system.

Antihistaminic drugs are used mainly in allergic diseases, in the initial stage of bronchial asthma, in Ménière’s disease, and similar ailments. A number of these drugs (dimedrol, diprazin) may be used to prevent motion sickness as well as to treat parkinsonism, chorea, and excessive vomiting in pregnancy and to relieve symptoms of radiation sickness and the like.

Antihistaminic drugs are taken internally according to a physician’s prescription, more rarely in subcutaneous, intramuscular, or intravenous injections. They are usually well-tolerated by patients; however, in some persons they cause dizziness. Prolonged use sometimes causes changes in the blood (leukopenia). Because of their depressive effect on the central nervous system, the majority of antihistaminic drugs should not be taken while performing work requiring rapid mental and physical reactions—for example, driving an automobile.

REFERENCE

Mashkovskii, M. D. Lekarstvennye sredstva,6th ed, parts 1–2. Moscow, 1967.

A. A. TSOFINA

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The commonest received treatment were the antihistaminic drugs (30.4%), corticosteroids (11.1%), bronchodilators (10.4%) and decongestants (8.1%).
Patient was then followed up with a course of Antibiotic for a week and antihistaminic drugs for a period of one month.
Present study has been targeted to develop the rapid and accurate spectrophotometric methods for the determination of five antihistaminic drugs; promethazine, diphenhydramine, desloratadine, levocetirizine, and loratadine.
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MRS resembles angioedema, but it can be differentiated with the lack of response to antihistaminic drugs, tendency to last longer and by causing fibrosis in the involved tissues (18).
Antihistaminic drugs are one of the most frequently and widely used systemic medications in dermatological disorders apart from corticosteroids and antibiotics.
Wound care, first generation antihistaminic drugs and methyl prednisolone (at a dose of 0.5-2 mg/kg/day for 6-30 days) were used in all patients.
The compound is used to denature alcohols such as ethanol and in the synthesis of sulfapyridine, antihistaminic drugs (tripelennamine and mepyramine), and in in vitro synthesis of DNA.
1785 patients (16.8%) with a history of allergic asthma or with a previous moderate, or severe, reaction to ICM, or one that included a respiratory component, were submitted to a three-drug prophylaxis scheme with corticosteroids and antihistaminic drugs. This scheme was performed according to the institutional guidelines and adapted from the European guidelines [8].
After care of the animal included IV infusion of fluids (1/2 litres Ringer lactate, 1/2 litres 5% Dextrose, 150 ml Calcium borogluconate), imidazole derivatives (Tinidazole 100 mililitres IV) and administration of antibiotics, anti-inflammatory and antihistaminic drugs. Antibiotics were also administered intrauterine.
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