Antihistamines

Source-This post on Antihistamines is based on the article “What are antihistamines?” published in “The Hindu” on 26th March 2024.

Why in the News?

There has been an increase in the intake of antihistamines to treat health concerns.

About Antihistamines

1. About Antihistamines: They are common drugs that can be purchased without a prescription. They are used to treat short-lived allergic reactions, like a sneezing fit or an itch.

2. How it functions: An antihistamine drug functions by targeting histamine receptors, which are proteins that bind to a compound called histamine in the body.

3. Its Composition: This compound is composed of ethylamine and imidazole, with the latter forming a ring structure.

4. Functions of Histamine: Histamine performs various roles in the body through four types of receptors: H1, H2, H3, and H4.

a) The H1 receptor is predominantly found in blood vessels, neurons, and smooth muscle cells, and its blockade helps alleviate minor allergies.

b) H2 receptors are present in gastric gland cells. They stimulate the release of gastric acid for digestion.

c) H3 receptors are located in the central nervous system. This regulates the release of neurotransmitters, including dopamine and serotonin.

d) H4 receptors control the body’s inflammatory response, including allergic reactions.

5. Research is currently focused on H3 and H4 receptors to develop specialized drugs for treating neurological and immunological disorders.

UPSC Syllabus: Science and technology