Allergies Common Treatments Antihistamines for Treating Nasal Allergies Second-generation antihistamines are generally preferred By Daniel More, MD Daniel More, MD, is a board-certified allergist and clinical immunologist with a background in internal medicine. Learn about our editorial process Daniel More, MD Medically reviewed by Medically reviewed by Corinne Savides Happel, MD on August 22, 2020 linkedin Corinne Savides Happel, MD, is a board-certified allergist and immunologist with a focus on allergic skin disorders, asthma, and other immune disorders. Learn about our Medical Review Board Corinne Savides Happel, MD on August 22, 2020 Print Histamine is a chemical released from allergic cells in the body (such as mast cells and basophils), usually in response to an allergen like cat dander or pollen. When histamine is released by allergic cells in the nose and eyes, the result is sneezing, runny nose, itchy eyes/nose/throat, nasal congestion, and post-nasal drip. These are the symptoms of hay fever, also known as allergic rhinitis. Antihistamines are medications that block the receptor for histamine, thereby stopping the symptoms that histamine causes. Antihistamines are the most commonly used medications to treat allergic rhinitis. BSIP / UIG / Getty Images Examples of Antihistamines Older antihistamines, called first-generation antihistamines, include: Benadryl (diphenhydramine)Chlor-Trimeton (chlorpheniramine)Atarax/Vistaril (hydroxyzine) These antihistamines have significant side effects termed “anticholinergic” side effects, which may include dry mouth, sleepiness, constipation, and urinary retention. Because of the side effects of these medications, they are generally considered to be too sedating for routine daytime use. Therefore, this article will only discuss the newer antihistamines, as described below. Newer antihistamines, called second-generation antihistamines include: Zyrtec (cetirizine)Allegra (fexofenadine)Clarinex (desloratadine) Claritin, Alavert (loratadine)Xyzal (levocetirizine) Each of the medications on the list above have a generic version available. These newer antihistamines tend to have fewer anticholinergic side effects and therefore are termed “low-sedating” or “non-sedating”. It's important to note that montelukast (Singulair), is not an antihistamine, but rather an antileukotriene medication. Leukotrienes are chemicals released from a variety of allergic and immune cells and may cause allergy symptoms, including nasal congestion. What Symptoms of Hay Fever Do Antihistamines Treat? Antihistamines block the action of histamine, and histamine-related symptoms include: SneezingRunny noseItchy eyesItchy noseItchy earsItchy throat Other symptoms, including post-nasal drip, cough, and nasal congestion may also be caused by histamine, and therefore can be treated by antihistamines. However, antihistamines are generally less effective at treating post-nasal drip and nasal congestion symptoms, since other chemicals other than histamine may be involved. Which Antihistamine Works the Best? The answer to this question is completely based on my experiences and opinions as a board-certified allergist. Studies are very helpful in deciding which medication works best, but it also must be kept in mind which company is paying for the study. It is my opinion that Zyrtec (cetirizine) and Allegra (fexofenadine) are very closely matched, and very good antihistamines. I think these medications work much better than either Claritin (loratadine) or Clarinex (desloratadine). At the present time, I feel that Zyrtec is the best antihistamine available in the U.S. for the treatment of allergic rhinitis. Which Antihistamine Causes the Least Amount of Sedation? The topic of sedation is an important one. Sedation refers to the concept that someone feels tired. This is different than impairment, which refers to the concept that someone’s ability to perform various mental and physical tasks is affected. The only truly non-sedating antihistamine currently available is Allegra. Zyrtec causes sedation 5% to 10% more than placebo. Claritin and Clarinex cause minimal sedation. None of these second-generation antihistamines, when used in recommended doses for allergic rhinitis, have been shown to result in impairment. This is in comparison to the older antihistamines, such as Benadryl, which are well known to result in the impairment of mental and physical tasks. Was this page helpful? Thanks for your feedback! Sign up for our Health Tip of the Day newsletter, and receive daily tips that will help you live your healthiest life. Sign Up You're in! Thank you, {{form.email}}, for signing up. There was an error. Please try again. What are your concerns? Other Inaccurate Hard to Understand Submit Article Sources Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy. Cleveland Clinic. Allergy overview. Last reviewed on March 7, 2016 Wheatley LM, Togias A. Clinical practice. Allergic rhinitis. N Engl J Med. 2015;372(5):456–463. doi:10.1056/NEJMcp1412282 Kawauchi H, Yanai K, Wang DY, Itahashi K, Okubo K. Antihistamines for allergic rhinitis treatment from the viewpoint of nonsedative properties. Int J Mol Sci. 2019;20(1). doi:10.3390/ijms20010213 Karrim N, Magula N, Saman Y. Antihistamines for motion sickness. Cochrane Database of Systematic Reviews 2017, Issue 7. Art. No.: CD012715. doi:10.1002/14651858.CD012715 Walsh GM, Annunziato L, Frossard N, et al. New insights into the second generation antihistamines. Drugs. 2001;61(2):207-36. doi:10.2165/00003495-200161020-00006 Naclerio RM, Bachert C, Baraniuk JN. Pathophysiology of nasal congestion. Int J Gen Med. 2010;3:47-57. doi:10.2147/ijgm.s8088 Thangam EB, Jemima EA, Singh H, et al. The role of histamine and histamine receptors in mast cell-mediated allergy and inflammation: the hunt for new therapeutic targets. Front Immunol. 2018;9:1873. doi:10.3389/fimmu.2018.01873 Pinto JM, Jeswani S. Rhinitis in the geriatric population. Allergy Asthma Clin Immunol. 2010;6(1):10. Published 2010 May 13. doi:10.1186/1710-1492-6-10 Additional Reading Allegra prescribing information. Aventis Pharmaceuticals. Wallace DV et al. The diagnosis and management of rhinitis: an updated practice parameter. J Allergy Clin Immunol. 2008 Aug;122(2 Suppl):S1-84. Zyrtec prescribing information. Pfizer Pharmaceuticals.