Antihistamines for Allergies: 6 Things an Allergist Wants You to Know

Here’s how to pick the right one for your symptoms.

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As you walk into the drug store pharmacy in a sneezy, watery-eyed haze, the last thing you need is to be overwhelmed by the vast selection of OTC allergy treatments. Which ones cause drowsiness? Will this help my nasal congestion? What can I do about these itchy eyes?!

“We have a lot of choices when it comes to over-the-counter allergy remedies,” says Clifford Bassett, MD, an allergist at NYU Langone Health and author of the book The New Allergy Solution. But don’t let the large allergy medication selection deter you. Along with allergy-proofing your lifestyle, over-the-counter and prescription medications are highly recommended by allergists and among the safest, most effective ways to fight your seasonal allergy symptoms.

A key to sifting through the many OTC allergy treatment choices? Know before you go: Ask your allergist about what brands they recommend, and brush up on the facts about the best meds for your seasonal allergy symptoms. Here’s what you need to know about a widely used OTC allergy medication called an antihistamine.

1. Antihistamines work by blocking a chemical called, well, histamine

When your body is exposed to allergens, like pollen, it makes histamines in an effort to remove the allergen from your body. The histamines attach to your cells, causing the cells to swell and leak fluid. This can then cause itching, sneezing, runny nose, and watery eyes.

Antihistamine medications work by preventing histamines from attaching to your cells, which therefore reduces symptoms. “[Antihistamines are] a very fundamental part of your regimen,” says Dr. Bassett.

2. Antihistamines are very helpful for certain allergy symptoms

Antihistamines are effective at fighting certain allergy symptoms, like sneezing, runny nose, and itchiness of the eyes. “Antihistamines work very well for most symptoms, but they don’t provide adequate relief for nasal congestion or stuffiness, which is a very common and bothersome symptom,” says Dr. Bassett.

3. For nasal symptoms, consider a steroid spray

Nasal steroid sprays work extremely well on all nasal symptoms, says Dr. Bassett, but only if used for a short time. Repeated use of these drugs, like oxymetazoline (Afrin, Dristan) or Tetrahydrozoline (Tyzine) for more than three consecutive days can result in a cycle of recurring or worsening congestion.

4. Antihistamines come in many forms

Antihistamines come as oral pills or liquids, nasal sprays (which are different from the steroid sprays described above) or gels, and eye drops. “Antihistamine eye drops work very well for relief of itching, red or watery eyes,” says Dr. Bassett.

Some antihistamines are only available by prescription, and others are available over the counter, meaning they don’t require a prescription.

5. Different antihistamines have different side effects

There are a few types of OTC antihistamines available: first generation, second generation, and third generation.

First-generation OTC antihistamines are some of the first antihistamines developed by scientists. They tend to cost less, but can have more side effects than newer drugs. “Some of the older or first generation antihistamines are effective, but they do cause drowsiness,” says Dr. Bassett. Some common first-gen antihistamines you can buy over the counter include:

  • Brompheniramine (brand names include Children’s Dimetapp Cold)
  • Chlorpheniramine (brand names include Chlor-Trimeton, Actifed Cold)
  • Dimenhydrinate (brand names include Dramamine)
  • Diphenhydramine (brand names include Benadryl, Nytol, Sominex)
  • Doxylamine (brand names include Vicks NyQuil, Tylenol Cold and Cough Nighttime)

Even though first generation antihistamines are effective, Dr. Basset says he (and many of his patients) prefers second- and third-generation antihistamines. “[With] second and third generation oral antihistamines, sedation or drowsiness is either not a problem or much less of a problem,” he says.

Second- and third-generation OTC antihistamines are newer medicines, and many provide relief from allergy symptoms without causing side effects, such as sleepiness. Common kinds include:

  • Loratadine (brand names include Alavert, Claritin)
  • Cetirizine (brand names include Zyrtec)
  • Fexofenadine (brand names include Allegra)

6. Read labels to take your meds safely

Generally speaking, it’s safe to take your allergy meds daily during allergy season, or less frequently if your symptoms aren’t as severe. Before you take any medication, be sure to read the label and take as directed. Don’t assume more medicine means it will work better; taking too much can be dangerous. Each person’s case of seasonal allergies is different, so if you have questions about how much to take, you’re currently taking a prescription medicine or if you’re unsure which OTC antihistamine medication is best for you, talk to your allergist.