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Indoor Allergens (cont.)


  • Antihistamines include older antihistamines, also called first-generation antihistamines, and newer second-generation antihistamines.

    • First-generation antihistamines: Most of these antihistamines are available without a prescription, such as diphenhydramine (Benadryl), clemastine (Tavist), and chlorpheniramine (Chlor-Trimeton Allergy). These older antihistamines are more likely to cause drowsiness. Depending on the product, the duration of action is often shorter than newer antihistamines and may necessitate taking the drug 3-4 times each day. These older antihistamines are more likely to cause dry mouth, urinary retention, constipation, and blurred vision.

    • Second-generation antihistamines: These antihistamines are also referred to as nonsedating antihistamines. Most are only available by prescription, such as cetirizine (Zyrtec), desloratadine (Clarinex), and fexofenadine (Allergra). The original second-generation antihistamines are now becoming available without a prescription (over the counter [OTC]), such as loratadine (Claritin). They can be taken over the long term with minimal side effects and are unlikely to cause sleepiness. The nonsedating antihistamines  are convenient to take since they are taken once or twice daily. They may allow you to carry on with your normal activities more easily than older first-generation antihistamines.
  • Decongestants are also available to decongest the nose when it is stuffy. Do not use decongestant nose sprays (such as Afrin) for more than 3 days, otherwise nasal congestion will reoccur.

  • Antiallergy eye drops: These may relieve severe itching, tearing, redness, or swelling of the eyes.

  • Corticosteroid nasal spray usually works better than do antihistamines. Corticosteroid nasal sprays relieve the congestion and swelling of the lining of the nose. These sprays take a few days to work and are best used every day to be most effective. They are safe to use because so little medicine is necessary for relief.

  • Corticosteroids (such as prednisone, methylprednisolone) are prescription medications taken by injection or by mouth that reduce inflammation and symptoms such as swelling.

  • Mast cell inhibitors, such as cromolyn sodium nose spray and eyedrops, may also be used to prevent histamine release and provide treatment locally for runny nose or watery eyes.

  • Leukotriene inhibitors, such as montelukast (Singulair) are starting to be used to prevent allergic symptoms. These are particularly useful for individuals whose asthma is easily triggered by allergies.
See Understanding Allergy and Hay Fever Medications for more information.

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