Allegra, also known by its generic name fexofenadine hydrochloride, is an antihistamine formulated for humans to treat allergies. Although it's not approved for use in canines by the U.S. Food and Drug Administration, your vet may prescribe it for your pup if he's dealing with nasal or skin allergies as an extra-label usage.
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 even itchy skin. This drug is particularly useful in treating canine allergic rhinitis. It's less effective and more unpredictable in treating skin allergies, though, and may not be your vet's first choice for treating pruritus in dogs. 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 pooch 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 Precautions
Allegra can cause sedation in canines, especially in high doses. It may not be safe for pregnant or nursing pooches, so consult with your vet first. Inform your vet if your pooch is taking any other medications because Allegra can interact negatively with erythromycin, ketoconazole and antacids containing aluminum and magnesium. Note that Allegra-D is a different medication and contains pseudoephedrine, a decongestant that is not safe for dogs; it can cause serious side effects if ingested.