Antihistamines can be used in dogs to relieve allergy symptoms or counteract allergic reactions. However, it is always best to talk to your veterinarian before giving any over-the-counter medications to your dog for several reasons. First, since human doses and doses for dogs are different, you need to know the correct dose to administer. Second, drug interactions can be dangerous, so your veterinarian should review your dog’s medical record to prevent any adverse events. Third, many over-the-counter (OTC) medications are NOT safe for dogs, and it is essential to read the label carefully to ensure that the product only contains antihistamine.
The most commonly used antihistamines for dogs include:
- Diphenhydramine (Benadryl®)
- Loratadine (Claritin®)
- Cetirizine (Zyrtec® or Reactine®)
- Chlorpheniramine (Chlortrimeton®)
- Hydroxyzine (Vistaril®)
Diphenhydramine (Benadryl®) is the most sedating antihistamine on the list, while 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.
According to the American Kennel Club (AKC), you can give the antihistamine Benadryl (diphenhydramine) to your dog, but you should always check with your vet first. 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. Other antihistamines safe for dogs include cetirizine, loratadine, and fexofenadine.
It is important to note that some liquid or rapid-dissolving tablet forms of antihistamines may contain the artificial sugar, xylitol, which is highly toxic to dogs. Please read labels carefully and do not use Xylitol-containing preparations (and do not EVER give your dog sugarless gum!). Other artificial sugars, such as sorbitol, are safe.
