Can Dogs Take Allegra?

Yes, dogs can take Allegra (generic name: fexofenadine), but only under the direct supervision and recommendation of a veterinarian. It’s an antihistamine commonly used to treat allergies in humans, and can also be used to treat similar symptoms in dogs.

However, it’s important to note that dosages for dogs are much lower than for humans and can vary based on the dog’s size, symptoms, and overall health. It’s crucial to never self-medicate your pet or give them human medication without a vet’s guidance, as it can lead to overdose and serious side effects.

Last Updated on September 20, 2023

Yes. Allegra can be a helpful medication when your dog is experiencing bad allergies. In fact, it’s very effective in preventing symptoms of canine allergic rhinitis and atopic dermatitis in dogs. There are specific versions of Allegra, however, like Allegra-D, children’s oral suspension, and 30mg oral dispersible tablet, that’s off-limits to dogs.

If you’re planning to give Allegra to your dog, this guide is a must-read for you.

dog holding ball

What is Allegra?

Allegra is an antihistamine medication formulated for humans to treat hay fever and skin itching. It contains an active ingredient called fexofenadine hydrochloride and is considered a second-generation antihistamine. This means that it doesn’t cause drowsiness, unlike first-generation antihistamines like Benadryl.

 Is it safe for dogs to take? Yes. Research studies have shown that it would take a high amount of medication for it to be considered toxic to dogs. Although it hasn’t been approved by the U.S Food and Drug Administration for canine use, some vets will prescribe it as an extra-label use to treat nasal or skin allergies in dogs. Not only that, but Allegra is also said to reduce the size of hotspots and relieve the itchiness caused by severe atopic dermatitis. However, only the tablet and gel cap forms are known to be safe for dogs.

A fair warning though, some dogs may be sensitive to the ingredients in Allegra. Hence, it shouldn’t be given to your dog unless your veterinarian says it’s okay.

You may also like: How Do You Prevent Hotspots on Dogs?

How does it work?

If you’re part of the population who suffers from seasonal allergies, then you know the constant struggle of dealing with a runny nose, sneezing fits, and watery eyes. But do you know why you get such symptoms?

It turns out that when our body is exposed to an allergen like pollen, for instance, it produces histamine. Your immune system recognizes the allergy trigger and signals the mast cells located in our skin, lungs, nose, mouth, gut, and blood to release histamine. This causes inflammation making your eyes water and your nose stuffy.

Conversely, most mast cells in dogs are found in their skin. This is why when your dog gets into contact with an allergic trigger, they begin to itch. With that said, Allegra doesn’t cure allergies. It only soothes your dog of the uncomfortable effects the allergy brings. For this same reason, properly identifying the cause of your dog’s allergy is more effective than treating its effects. Now, what are the common causes of allergy?

dog standing

Common causes of dog allergies 

  • Dander
  • Mold
  • Feathers
  • Food ingredients (like grains found in dog foods)
  • Cigarette smoke
  • Dust

Symptoms of Environmental Allergy 

  • Vomiting
  • Intestinal upset
  • Sneezing
  • Intense itching
  • Hair loss
  • Watery eyes
  • Paw licking and biting
  • Sores, redness, or swelling on your dog’s paws 

The recommended dosage for dogs

For optimal results, the dose recommended by your veterinarian should be followed. He will provide you with the right dose based on your dog’s age, weight, and other medicines he is taking. However, for informational purposes, these are the usual doses.

Allegra is recommended at a rate of 1-2.5 mg per pound of body weight. Some vets will advise you to administer it twice per day. While some prefer it once a day. If your vet does recommend it twice per day, using the tablet form rather than the gel cap form may be better as it’s easier to split into two.

Allegra is available in 30, 60, and 180 mg tablets. Generally, the formulation that’s prescribed by veterinarians is the ones where the active ingredient is only fexofenadine hydrochloride. Allegra in 60mg, however, is thought to have a higher margin of safety. The following is the recommended daily dosage for a 60mg tablet:

  • Toy dogs weighing from 4-12lbs ½ tablet
  • Small dogs weighing 13-25lbs 1 tablet
  • Medium-sized dogs weighing 26-50lbs 1 ½ tablet
  • Large dogs weighing more than 50lbs 2 tablets

You may administer fexofenadine with or without food. Although if your dog tends to experience gastrointestinal upsets, food may be a good idea. 

Warning: This is only for informational purposes and not a substitute for experts’ advice. 

siberian husky

Side effects of Allegra for dogs 

Interestingly, compared to other antihistamines, Allegra has fewer side effects. And even better, it can even have fewer side effects when properly instructed by a vet. Some of them are:

  • Nausea
  • Dry mouth
  • Indigestion
  • Lethargy
  • Vomiting
  • Diarrhea

Additionally, a long-term side effect of second-generation antihistamines is it may prolong QT intervals and arrhythmias if given in high doses. If your dog shows signs of vomiting and coughing after taking Allegra, treat it as an emergency, and call your vet immediately.

How often and how long should I give Allegra to my dog?

While it may be very hard for dogs to overdose on antihistamines, it doesn’t mean you shouldn’t exercise caution. You should not give more than the recommended dose unless your veterinarian says so. The treatment duration usually lasts for two weeks. But it can vary based on your pet’s response to the medication, the severity of the problem, and whether or not your dog is showing any adverse effects.

When does Allegra become unsafe for dogs?

While Allegra is deemed safe for dogs, liquid suspension, Allegra D, and the 30 mg dispersible tablet contain toxic ingredients. The children’s oral suspension formula has Xylitol that can be dangerous for dogs when ingested. The Allegra D formula also contains a decongestant called pseudoephedrine – another toxic substance for dogs. The 30 mg designed to dissolve in the tongue of humans may also be hard to do for dogs.

It is also possible to have a negative interaction with other medications. Erythromycin, ketoconazole, and antacids are one of them. Some safety guidelines also include:

  • Do not give to pregnant and nursing dogs
  • Do not give to dogs who suffer from kidney diseases
  • Should not be given with fruits or fruit juices

dog giving his paw

Other antihistamines

Allegra is not the only antihistamine available for treating allergy symptoms in dogs. But one rule you must always apply when buying over-the-counter medications is to read the label. Make sure that there is no Xylitol nor decongestant in it.

Helpful tip: Don’t give your dog any antihistamines ending in D like Claritin-D or Allegra-D. They most likely contain decongestants. 

Other treatments 

While under the medication, there are other things you can do to relieve your pet from his allergies. One of them is to bathe your dog for 10 minutes with oatmeal dissolved in cold water. You can also try a baking soda solution and pouring it over the itchy parts. Washing your dog’s bedding once a week to remove dander and pollen may also help. If your dog is allergic to grains, switching to grain-free dog foods is ideal. You can use our guide: Best Grain-free Dog Food to help you. 

Also related: Best Dog Beds


Allegra can be a potent drug to relieve your dog of itchiness. But determining the underlying cause of the allergy can not only give you a knock-out punch for the symptoms but prevent future allergies as well.



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