What are antihistamines used for?

They are mainly used for allergies — hay fever, allergic reactions, hives and itchy skin, and reactions to insect bites and stings. Some are also used for travel sickness or to help with sleep, though that is a separate use.

What is the difference between drowsy and non-drowsy antihistamines?

Older "first-generation" antihistamines can make you sleepy, while newer "second-generation" ones usually do not. For daytime allergy relief, a non-drowsy type is often preferred. A pharmacist can advise which suits your needs.

Can I take antihistamines every day?

Many people take a non-drowsy antihistamine daily during allergy season, and this is generally fine. If you find you need them long term or they are not controlling your symptoms, speak to a pharmacist or GP.

Do antihistamines treat a severe allergic reaction?

No. Antihistamines help mild to moderate allergy symptoms but are not a treatment for anaphylaxis — a severe, life-threatening reaction. That needs emergency treatment (adrenaline) and a 999 call.

Antihistamines | HealthAnswers

Quick answer

What is antihistamines used for?

Antihistamines are medicines that ease allergy symptoms such as sneezing, itching, a runny nose and hives. They work by blocking histamine, a chemical the body releases during an allergic reaction. Some cause drowsiness and some don't, and most are available from pharmacies.

What are antihistamines?

Antihistamines are medicines that relieve the symptoms of allergies. When you have an allergic reaction, your body releases a chemical called histamine, which causes symptoms like sneezing, itching and a runny nose. Antihistamines work by blocking histamine, calming these symptoms down.

What they are used for

Antihistamines are commonly used for:

hay fever and other allergies
hives (urticaria) and itchy skin
reactions to insect bites and stings
allergic conjunctivitis (itchy, watery eyes)

Drowsy and non-drowsy types

There are two broad groups. Older antihistamines can make you feel sleepy, which is why some are also used to help with sleep. Newer ones are usually “non-drowsy” and are generally preferred for daytime use, such as managing hay fever while at work. A pharmacist can help you choose.

Using them safely

Antihistamines are available in tablets, liquids, nasal sprays and eye drops. To use them well:

follow the instructions on the packet or your prescription
if using a drowsy type, do not drive or operate machinery until you know how it affects you
tell a pharmacist about other medicines you take, as some can interact

Always read the patient information leaflet.

An important limit

Antihistamines help with everyday allergy symptoms, but they are not a treatment for a severe allergic reaction (anaphylaxis). If someone has swelling of the face, lips or throat, difficulty breathing, or feels faint, this is an emergency — call 999 immediately.

Common questions

What are antihistamines used for?: They are mainly used for allergies — hay fever, allergic reactions, hives and itchy skin, and reactions to insect bites and stings. Some are also used for travel sickness or to help with sleep, though that is a separate use.
What is the difference between drowsy and non-drowsy antihistamines?: Older "first-generation" antihistamines can make you sleepy, while newer "second-generation" ones usually do not. For daytime allergy relief, a non-drowsy type is often preferred. A pharmacist can advise which suits your needs.
Can I take antihistamines every day?: Many people take a non-drowsy antihistamine daily during allergy season, and this is generally fine. If you find you need them long term or they are not controlling your symptoms, speak to a pharmacist or GP.
Do antihistamines treat a severe allergic reaction?: No. Antihistamines help mild to moderate allergy symptoms but are not a treatment for anaphylaxis — a severe, life-threatening reaction. That needs emergency treatment (adrenaline) and a 999 call.

Sources

NHS — Antihistamines