Can I Give My Dog Allegra for Allergies?

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Just like humans, dogs get allergies, and the triggers are often the same. You might find your pup having a histamine reaction to grass pollen, tree pollen, mold, dust, and — in some cases — even ​other​ dogs and cats. In fact, in the same way you might be allergic to your dog, your dog might be allergic to you. This is where allergy medicine for dogs comes in.


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Allegra, also known by its generic name fexofenadine hydrochloride, is typically used to treat allergies in humans, but it's also a common treatment for allergies in dogs. This type of canine treatment isn't approved by the U.S. Food and Drug Administration, so it's important to consult your vet. As with most OTC medications intended for humans, there may be ingredients in certain fexofenadine hydrochloride products that can cause an Allegra dog overdose.


Whether you're looking to treat your pup's allergies or nervous because your dog ate Allegra without a prescription, here's what you need to know about Allegra and dogs.

Identifying allergies in dogs

Though dogs can have the same types of allergies as humans, the way they present is a little bit different. While you might find yourself sneezing during pollen season, canine allergic rhinitis or allergic conjunctivitis is less common.


Since a dog's histamines cells are located in their skin, an allergic reaction typically results in skin irritation. You may notice your dog scratching, licking, and/or biting areas of their body. You may also notice red or inflamed patches on your dog's skin, known as "hot spots," which are actually a secondary infection that happens after the healthy protective barrier on your dog's skin breaks down.


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Hot spots can't be treated at home with OTC allergy medicine for dogs. Allegra only treats the underlying histamine reaction, not the lesion. Instead, your vet may prescribe a topical or oral steroid to prevent the hot spot from becoming infected.


How does Allegra work?

Allegra is an H1 receptor antagonist that stops your pup's body from producing chemicals called histamines. Histamines can cause sneezing, a stuffy nose, and itchy skin. Though allergic rhinitis is less common in canines, this drug is a particularly useful treatment. It's less effective and more unpredictable in treating skin allergies in dogs and may not be your vet's first choice for treating pruritus.


Overall, Allegra is generally considered safe for dogs​,​ according to the "Canine and Feline Dermatology Drug Handbook." Your vet will prescribe the proper dose for your particular pup based on his size and weight. This medication is usually given one to two times daily and comes in 30, 60, and 180 mg tablets.


Side effects and Allegra dog overdose

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If your dog ate Allegra without a prescription, it may not be a major cause of concern. Allegra dog overdoses are rare — as long as the medication does not include an unsafe decongestant. The Canine and Feline Dermatology Drug Handbook found no evidence of toxicity in dogs who took up to 2000 mg/kg of fexofenadine hydrochloride (or 300 times the recommended dose for adult humans). Though Allegra has minimal side effects, it may cause drowsiness, especially in larger doses.


Unfortunately, OTC allergy medicines containing fexofenadine hydrochloride often have other ingredients that aren't safe for dogs, so you'll need to carefully check the bottle. For example, Allegra-D contains the decongestant pseudoephedrine, which should never be consumed by canines. If your dog ate Allegra containing this ingredient, call your local veterinarian or the ASPCA Animal Poison Control Center at (888)-426-4435, immediately.

As with all medications for your pup, it's important to first consult your vet before giving your dog an OTC antihistamine. Allegra can interact negatively with medicines like erythromycin, ketoconazole, and antacids containing aluminum and magnesium. It may also be unsafe for pregnant or nursing pups.

Other allergy medicines for dogs

Allergy medicine for dogs is often the same as allergy medicine for humans and extends far beyond Allegra. Dogs may also be prescribed Claratine (loratadine), Benadryl (diphenhydramine), or Zyrtec (cetirizine), which are commonly found in your local pharmacy.

If your dog does not respond to antihistamine treatment, you may need to look into additional options like immunotherapy or steroids. It may also help to give your dog more frequent baths, keep your home free from dust and mold, or try other home remedies.

Always check with your veterinarian before changing your pet’s diet, medication, or physical activity routines. This information is not a substitute for a vet’s opinion.



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