What should you know about popular antihistamines?

Antihistamines block the action of histamine, a chemical involved in allergy symptoms. They may ease a runny or blocked nose, itchy throat and itchy eyes linked with allergic rhinitis or allergic conjunctivitis. They do not remove the trigger, cure every cause of congestion or replace emergency treatment for a severe reaction.

Some products can cause drowsiness, slower reactions, dry mouth or blurred vision. Others are less sedating for many people, but individual responses vary. Conditions such as glaucoma, prostate problems, pregnancy and liver or kidney disease can affect the safest choice.

Read the active ingredient and follow the package or clinician's directions; avoid taking two products with the same antihistamine. Do not drive, operate machinery or drink alcohol until you know how the medicine affects you. Check with a pharmacist before combining it with sedatives, sleep medicines or other cold remedies.

Reducing exposure to a known trigger can improve control. For example, people with Pet Allergy or House Dust Mite Allergy may need an avoidance plan as well as symptom relief. A pharmacist can help compare formulations for the symptom you have.

Seek emergency help for swelling of the lips, tongue or throat, difficulty breathing, faintness or rapidly spreading hives. Arrange medical advice when symptoms persist, recur without a clear trigger, disturb sleep or do not respond to suitable use.

Ask which ingredient suits your symptoms, whether it is safe with your medicines or conditions, how long to use it and whether you need assessment for Allergic Rhinitis or Allergic Conjunctivitis.