Fexofenadine is also available an oral suspension that contains xylitol (NOTE: Xylitol may be toxic in dogs). The human oral suspension is not recommended for use in pets.
fexofenadine (Telfast®) – this is a second gen. It is available as 60 mg capsules and 120 or 180 mg tablets. The dose is 5–10 mg/kg once or twice daily (don't use if your dog is on ketoconazole or a macrolide antibiotic)
Diphenhydramine (Benadryl®), cetirizine (Zyrtec®), and loratadine (Claritin®) are commonly used antihistamines that relieve allergy symptoms or counteract allergic reactions. Antihistamines are usually safe but can make some dogs drowsy and others hyperactive.
Although the U.S. Food and Drug Administration has not approved Benadryl for dogs, it is safe in the appropriate dose, and it is commonly used by vets to treat skin allergies that cause itching and scratching. Benadryl can be used to treat dogs with: Hives.
Antihistamines with the active ingredients of diphenhydramine, chlorpheniramine, cetirizine, clemastine or loratadine are usually safe for most healthy adult dogs. Hydroxyzine is another dog-safe antihistamine and one of the most effective available, but it's only available on prescription.
Fexofenadine, commonly known as Allegra® or Telfast®, is a second generation antihistamine drug that may be used for dogs and cats to control itching and other signs related to allergic conditions. Fexofenadine is considered less sedating than other antihistamines.
How quickly does Telfast start working? Telfast works within 1 hour of taking the recommended dosage.
Benadryl Tablets
According to the Merck Veterinary Manual, the standard dose for Benadryl is 2-4 milligrams per kilogram of body weight, or 0.9-1.8 milligrams (mg) of Benadryl per pound. Therefore, a simple and practical dose is 1 mg of Benadryl per pound of your dog's weight, given 2-3 times a day.
Cetirizine (brand name Zyrtec®, Reactine®) is an antihistamine used to treat pruritus (itching) associated with atopic dermatitis, urticaria (hives), and insect-bite reactions in cats and dogs. Its use is in cats and dogs is 'off label' or 'extra label'.
The most common antihistamine for dogs is diphenhydramine (brand name Benadryl). Also found in ProSense Dog Itch & Allergy Solutions Tablets, diphenhydramine is safe in most dogs if given in the recommended dosage of 1 mg of diphenhydramine per pound of body weight given by mouth.
The 10 mg pills are okay for dogs between 10 and 50 lbs, though 5-10 lb dogs should only take half (or a 5-mg tablet.) Canines who exceed 50 lbs may take up to two 10 mg tablets if necessary. Dogs under 5 lbs should only take a quarter of a 10 mg tablet or half of a 5 mg pill.
Quercetin: A Natural Antihistamine For Dogs
Are you looking for a natural anti-histamine for dog allergies? Quercetin is a bioflavonoid that acts as an antihistamine for dogs and has antioxidant and anti-inflammatory properties. Many veterinarians suggest Benadryl or Apoquel for allergies in dogs.
Side effects tend to be minimal, although some pets do become drowsy. The dosing schedule is also much more convenient, with dogs weighing over 10 lbs getting a single 10mg tablet once daily.
The most commonly known antihistamine is Benadryl, says Dr. Shah, but it can cause drowsiness. That's why he recommends second-generation antihistamines like Claritin, Zyrtec, or Allegra, which are less sedating.
Telfast 180mg is the highest strength of Telfast available — it contains 180mg of the active ingredient fexofenadine hydrochloride (HCl). Fexofenadine HCl acts quickly (within 1 hour) without causing drowsiness to help relieve the symptoms of hayfever allergies by blocking histamine receptors in the body.
Cetirizine (Zyrtec® or Reactine®) is one of the most commonly used over-the-counter antihistamines recommended by veterinarians. Claritin® can be used but is not typically recommended by veterinarians as some forms of Claritin® contain decongestants such as pseudoephedrine which is very toxic to dogs.
It is recommended to give your dog 0.5mg per pound of body weight. You can safely give Zyrtec to your dog up to 20 mg per day. It should only be administered orally.
Cetirizine (Zyrtec) ¼ - ½ mg per pound (one 10mg tab per 30-40 lbs) twice daily. Loratadine (Claritin): ¼ mg per pound (half of a 10mg tablet per 20 lbs) once daily. Clemastine (Tavist-1, Antihist-1): 0.02mg per pound (one 1.34mg tablet per 65lb dog) twice daily.
Several over-the-counter (OTC) human antihistamines can work to help relieve dog allergy symptoms, but we recommend that you consult with your veterinarian before administering any of these medications. Benadryl (diphenhydramine) is the most popular antihistamine for humans and can be effective for dogs as well.
Apoquel starts relieving allergic dog itch and inflammation due to skin allergies within 4 hours — and controls it within 24 hours. The #1 prescribed medicine for allergic itch in dogs.
When accidentally ingested by dogs and cats, antihistamine poisoning can result in clinical signs of severe agitation, lethargy, sedation, aggression, abnormal heart rate, abnormal blood pressure, vomiting, diarrhea, inappetance, seizures, respiratory depression, and even death.
When strict flea control is not possible, or in cases of severe itching, your veterinarian may prescribe antihistamines or corticosteroids (steroids) to block the acute allergic reaction and give immediate relief. If a secondary bacterial infection is present, an appropriate antibiotic will be prescribed.
Apple cider vinegar, coconut oil, or aloe vera can be put on the skin to calm any itching. A relaxing oatmeal bath can relieve itching, burning, and dry skin.