Antihistamines vs Decongestants

Many people are confused about when to use an antihistamine vs a decongestant, which is not surprising since these medications both treat allergy symptoms, and in fact, are frequently put together in combination products. Here is a quick breakdown:

Antihistamines work “anti” (against) histamine, which is a chemical released in the body during an allergic response. Histamine causes itchy eyes, tearing, itchy nose, sneezing, and post-nasal drainage that creates scratchy or sore throats, as well as occasionally causing total skin itching or hives. Antihistamines, therefore, help decrease sneezing, dry up dripping noses, eyes and throats, and reduce hives.

Antihistamines may cause drowsiness, especially the original over the counter antihistamine known as diphenhydramine (brand name Benadryl.) More recently developed antihistamine products such as brand name Allegra, Claritin & Zyrtec are considered “non-sedating”, but may still cause drowsiness in some people. All antihistamines cause some dryness of the mouth and nose- that is part of the goal.

Decongestants simply constrict blood vessels, which in the nose reduces that feeling of stuffiness. Decongestants alone do not affect sneezing, itchiness or sore throats. Decongestants are stimulating, similar to caffeine. Therefore, decongestants may cause some shakiness or anxiety, increased heart rate or increased blood pressure, or insomnia.

Both antihistamines and decongestants come in oral liquids, pills, and nasal sprays. Nasal decongestants should only be used very short term, however, because after a couple days of use, the body creates rebound congestion that defeats the purpose of using the decongestant.

Which should you keep in your first aid kit?

  1. Diphenhydramine (Benadryl)- this is a sedating antihistamine; great for occasional difficulty falling asleep or for immediate treatment of an allergic reaction to a sting, food or medication.
  2. NONsedating antihistamine of choice: for daytime use-choose a generic or brand name medication such as Allegra, Claritin or Zyrtec for seasonal allergic symptoms of sneezing, itching, drippy eyes, nose or throat or for hives.
  3. Decongestant: phenylephrine is a common simple decongestant (the little red pills, common brand name Sudafed). Use when you have a stuffy nose. Okay to use the decongestant sprays (such as Afrin) for less than three days only; provides immediate effect to reduce stuffy nose sensation.

BOTTOM LINE: Rather than combination products, choose an antihistamine or decongestant separately based upon your specific symptoms.

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