Antihistamines are drugs that treat allergy symptoms. When taken by mouth, they come as pills, chewable tablets, capsules, and liquids.
Antihistamines treat these allergy symptoms:
Treating symptoms can help you or your child to feel better during the day and sleep better at night.
Depending on your symptoms, you can take antihistamines:
For many people with allergies, symptoms are the worst around 4 a.m. to 6 a.m. Taking an antihistamine at bedtime may help you or your child feel better in the morning during allergy season.
You can buy many different brands and forms of antihistamines without a prescription.
Ask your health care provider what type of antihistamine and what exact dosage is right for you or your child. Make sure you understand how much to use and how many times a day to use it. Be sure to read the label carefully. Or ask your pharmacist if you have questions.
Ask your health care provider if antihistamines are safe for you or your child, what side effects to watch for, and how antihistamines may affect other medicines you or your child take.
There may be special precautions for using antihistamines if you have:
Side effects of antihistamines may include:
Call your doctor if:
Corren J, Baroody FM, Pawankar R. Allergic and nonallergic rhinitis. In: Adkinson NF Jr., Bochner BS, Burks AW, et al., eds. Middleton's Allergy Principles and Practice. 8th ed. Philadelphia, PA: Elsevier Mosby; 2013: chap 42.
Greiner AN, Hellings PW, Rotiroti G, Scadding GK. Allergic rhinitis. Lancet. 2011;378(9809):2112-2122.
Wasserman SI. Approach to the person with allergic or immunologic disease. In: Goldman L, Schafer AI, eds. Goldman's Cecil Medicine. 24th ed. Philadelphia, PA: Elsevier Saunders Elsevier; 2011:chap 257.
Updated by: Stuart I. Henochowicz, MD, FACP, Associate Clinical Professor of Medicine, Division of Allergy, Immunology, and Rheumatology, Georgetown University Medical School. Also reviewed by David Zieve, MD, MHA, Isla Ogilvie, PhD, and the A.D.A.M. Editorial team.
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