Should I Take Antihistamines For Allergies?

antihistamines for allergies
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When suffering from allergies, you must be desperate for quick relief from all the runny and congested nose. You can get antihistamines for allergies of your choice as some can cause less sleepiness which is good if you work. However, the question is, at what point of allergy should you be getting antihistamines?

Medically Reviewed by Dr. K on 14th February 2022.

 Should I Take Antihistamines For Allergies?

Allergies may be treated with various medicines, including steroids and allergy injections, but an antihistamine is generally the first option. Histamines are chemicals made by the immune system to defend against harmful pathogens. To do so, they arrive at areas of the body exposed to a potential threat via the bloodstream, where they cause tissues to become inflamed. Although a key part of the body’s immune response, sometimes the body mistakenly recognises a molecule as harmful- such as pollen- leading to a host of allergic symptoms from a runny nose and itchy eyes to a sore throat. Antihistamines are thus an obvious solution to reduce these symptoms. 

How Antihistamines Treat Allergies

When your body comes into touch with an allergy trigger, such as pollen, ragweed, pet dander, or dust mites, it produces substances known as histamines. They cause your nasal tissue to expand (making it stuffy), your eyes and nose to run, and your eyes, nose, and mouth to itch. You may also get an itching rash on your skin known as hives.

Antihistamines work by reducing or blocking histamines, thus alleviating allergy symptoms.

These medications effectively alleviate the symptoms of many allergies, including seasonal (hay fever), indoor, and food allergies. However, they are unable to alleviate all symptoms.

Your doctor may prescribe a decongestant to relieve nasal congestion. Some antihistamines and decongestants are combined in one pill.

What Types of Antihistamines Are Available?

Tablets, pills, liquids, nasal sprays, and eyedrops are just some of the options of antihistamines for allergies. Some medications are only accessible with a prescription. Others are available at your local drugstore over the counter (OTC).

Antihistamines for allergies on prescription include:

  • Azelastine eye drops (Optivar)
  • Azelastine nasal sprays (Astelin, Astepro)
  • Carbinoxamine (Pelagic)
  • Cyproheptadine
  • Desloratadine (Clarinex)
  • Emedastine eyedrops (Emadine)
  • Hydroxyzine (Atarax, Vistaril)
  • Levocabastine eyedrops (Livostin)
  • Levocetirizine oral (Xyzal)

Antihistamines available over-the-counter include:

  • Brompheniramine (Dimetane)
  • Cetirizine (Zyrtec)
  • Chlorpheniramine (Chlor-Trimeton)
  • Clemastine (Tavist)
  • Diphenhydramine (Benadryl)
  • Fexofenadine (Allegra)
  • Loratadine (Alavert, Claritin)

Eyedrops are used to treat the symptoms of allergies in the eyes, such as itchy, watery eyes. To relieve congestion, several medicines mix an antihistamine with a decongestant.

Side Effects of Antihistamines

Older ones are more likely to produce adverse effects, especially sleepiness.

Newer antihistamines for allergies may be a better option for some individuals since they have fewer adverse effects.

The following are some of the most common antihistamine adverse effects:

  • Dry mouth
  • Drowsiness
  • Dizziness
  • Vomiting and nausea
  • Moodiness or restlessness (in some children)
  • Urinating problems or inability to urinate
  • Blurred vision
  • Confusion

If you're taking a drowsy antihistamine, take it before sleep. Do not take it before driving or using equipment during the day.

Before you take allergy medication, read the label. Antihistamines have the potential to interfere with other medicines you're taking.

See your doctor first if you have an enlarged prostate, heart disease, high blood pressure, thyroid issues, kidney or liver illness, a bladder blockage, or glaucoma. If you're pregnant or breastfeeding, talk to your doctor.


  2. American Academy of Allergy, Asthma & Immunology: “NAB: Frequently Asked Questions."
  3. AAAAI Allergy & Asthma Medication Guide: “Tips to Remember: Asthma & Allergy Medications."
  4. Rakel, D. Integrative Medicine, 2007.
  5. Wallace, D.V. Journal of Allergy and Clinical Immunology, August 2008.
  6. Motala C. Current Allergy & Clinical Immunology, June 2009.

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