5 Things to Know About Over-the-Counter Antihistamines

Roni Shye
Roni Shye, PharmD BCGP BCACP, is a licensed pharmacist in the states of Florida, Ohio, and Pennsylvania.
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Over-the-counter (OTC) medications can be quick, easy, and convenient options to ease minor aches and pains, the common cold, or seasonal allergies.

Antihistamines are one of the most commonly used OTC medications, including allergy treatments like Allegra (fexofenadine) and Zyrtec (cetirizine), or a sleep aids like Nyquil (which often contain diphenhydramine—also known as Benadryl).

These 5 facts will help you choose the right OTC antihistamine.

  1. If you suffer from seasonal allergies, OTC antihistamines like Claritin (loratadine), Zyrtec (cetirizine) and Allegra (fexofenadine) can give you relief without a visit to your doctor and let you choose the treatment that will work best for you. You can—and should—still ask your doctor or pharmacist if you aren’t sure what to take.
  2. There are different types of antihistamines. Older antihistamines are considered first generation, while the newer options are second and third generation antihistamines.
    The older first-generation antihistamines have been around for more than 60 years and can be very sedating. The most common example is Benadryl (diphenhydramine). Diphenhydramine is now often found in OTC sleep aids, cough and cold preparations, and combination with pain relievers as in Advil PM or Tylenol PM.
    The newer second- and third-generation antihistamines cause less drowsiness and only need to be taken 1 to 2 times daily compared to the first generation antihistamines which may be taken 4 to 6 times daily. Second-generation antihistamines include Zyrtec (cetirizine) and Claritin (loratadine). Allegra (fexofenadine) is currently the only third-generation antihistamine available without a prescription.
  3. Older antihistamines can cause falls in the elderly. Antihistamines can have many side effects including sedation, drowsiness, or dizziness—all of which can lead to falls, especially for the elderly. Although many antihistamines claim to be non-drowsy, they should be with caution in anyone 65 years of age or older because of the increased risk of falls.
    Which antihistamines should you avoid over 65? A good guideline is the “Beers list,” created in 1991 by Dr. Mark Beers to identify potentially inappropriate medications for nursing home residents. This list is continually updated as new medications come along, but these antihistamines are currently on the list:

  4. Older antihistamines can cause urination problems. Antihistamines basically work by “drying you up”—so anything involving fluid in your body will decrease—including urine. The inability to urinate can be a problem for many older patients specifically those who already have urinary problems like benign prostatic hyperplasia (BPH), or incontinence. The inability to completely urinate can also increase the risk of urinary tract infections, especially in women.
  5. Some of the newer antihistamines come in combination with Sudafed (pseudoephedrine). Some examples: Allegra-D, Claritin-D, and Zyrtec-D. Pseudoephedrine can help with nasal congestion, but be aware—you will need to pick up these medications from your pharmacy’s counter, just like when you purchase Sudafed alone.

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