Antihistamines

About Antihistamines

Anti-histamines are useful in the treatment of allergies such as hayfever. They can also be used to treat itching, hives, and more severe allergic reactions like anaphylaxis. Anti-histamines will relieve symptoms of sneezing, nose and eye irritation and itching, and runny nose.

There are broadly two groups, sedating and non-sedating types, and while some anti-histamines are available to buy over the counter from your pharmacist, others are only available on prescription.

How do Antihistamines work?

Antihistamines are medicines which act by blocking the action of histamine in the body. Histamine is the chemical released in allergic reactions as well as other some other reactions that mimic allergies but don't have a clear cause. Histamine causes your skin to itch, eyes to water and your nose to run.

Antihistamines tend to work quickly; usually within 30 minutes after being taken, and the duration of treatment varies depending on the reason you take them for. For some people it can be as short as one week if treating itching, but for instance in people with hayfever they would take the medicine throughout the pollen season.