What should you know about H2 antihistamines over the counter?

A medicine sold without a prescription is still a medicine with precautions. Antihistamines reduce the effects of histamine and may help sneezing, runny nose, itchy eyes, itchy throat, and some allergy-related congestion. They can be useful for allergic rhinitis, allergic conjunctivitis, pet allergy, and house dust mite allergy, but they do not remove the trigger or treat every cause of a blocked nose.

Some products cause sleepiness, slower reactions, dry mouth, blurred vision, or difficulty passing urine. Less-sedating options may still affect alertness. Cold and flu products can contain an antihistamine, so reading the ingredient list prevents accidental duplication.

Ask a pharmacist to match the product with your main symptom and check the label for age limits, active ingredient, dose, and warnings. Do not take more than directed or combine antihistamines without professional advice. Avoid alcohol and do not drive or use machinery if you feel sleepy or slowed.

Seek advice before use if you are pregnant or breastfeeding, giving it to a child, or have glaucoma, urinary problems, liver or kidney disease, or heart-rhythm concerns. Mention sleeping tablets, calming medicines, and all other treatments.

Emergency care is needed for swelling of the mouth or throat, breathing difficulty, faintness, or rapidly spreading hives. Arrange a review if symptoms are severe, keep returning, disturb sleep, affect vision, or fail to improve with correct use. Persistent nasal symptoms may need a different diagnosis or treatment.

Ask which non-prescription option fits your symptoms, whether it causes drowsiness, how it fits with your medicines, and how long you should use it before seeking review.