Antihistamines work by physically blocking the H1 receptors, stopping histamine from reaching its target.This decreases your body's reaction to allergens and therefore helps to reduce the troublesome symptoms associated with allergy.Antihistamines are a group of medicines which act by blocking the action of the chemical called histamine in the body.Either H1 or H2 histamine receptors can be blocked by medicines, but the group commonly known as antihistamines blocks the H1 receptor.Chlorphenamine is the antihistamine most used in an emergency situation such as anaphylaxis, and may be given by injection in this situation.
Your doctor or pharmacist may advise or prescribe a particular antihistamine depending on the cause of your allergy and on whether you require a sedating or non-sedating medicine.They have a number of uses, but are most often used to treat allergies.If you are one of the many people who get hay fever each year, you will know all about antihistamines.This is one of the most common uses of antihistamines. For example: Histamine is a chemical naturally produced by various cells in your body. Large amounts of histamine are made in cells called mast cells, in places where the body comes into contact with the outside environment. Here, mast cells and histamine form part of your immune defence system.(Whereas, in the stomach, histamine made by cells that line the stomach helps to produce acid for food digestion.) Your immune system cells monitor your blood and mucosae for anything (for example, germs such as bacteria or viruses) that is not made by your body.