loratadine for dogs
Category_Dog Knowledge
Medical Concern
The Vet's Corner

Claritin for Dogs: Uses, Dosage, & Side Effects

by Jeff Bloom

Written By: Tiffany Ruiz Dasilva, VMD, cVMA | Professional Services Veterinarian, Wild Earth

If your dog has experienced an allergic reaction in the past or suffers from allergies, you may have wondered whether there are any over-the-counter medications that could help. While many over-the-counter human medications are unsafe for your dog, several antihistamines such as claritin, benadryl and zyrtec are safe to give your dog at the right dose under veterinary supervision.

Before giving your dog any medication, it’s vital to know when it is appropriate to give it, potential side effects, and the correct dose. It may surprise you to know that human and dog doses differ, and even some “safe” medications can be dangerous if your pet has a certain condition or is taking other medications.

How Claritin Works

Claritin is an antihistamine drug that treats allergic symptoms, including itchiness and inflammation. When a dog’s immune system identifies a foreign substance as an allergen, mast cells release histamine which binds to H1 receptors, resulting in symptoms such as redness, swelling, and itchiness. Loratadine, the active chemical in Claritin, works by binding to the H1 receptor, blocking histamine from binding.

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There are several formulations of Claritin on the market, and some can be toxic to your dog. Always check the label to make sure that the only active ingredient is loratadine. Claritin-D should never be administered to your dog as it contains pseudoephedrine which is lethal to dogs. Additionally, do not give chewable, or slow-release versions.

Uses of Claritin For Dogs

Claritin can be administered to dogs to treat the following conditions:


The three most common allergies in dogs are food, environmental and flea allergies. Itching, inflammation, and redness are common symptoms. Claritin can possibly help with skin irritation caused by allergies.

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Bites and Stings

Insects bites or stings can cause your pet to have an allergic reaction. If the reaction is mild, such as swelling, itching, or hives, you can consider giving Claritin to reduce these symptoms under the direction of a veterinarian. If your pet has any facial swelling or difficulty breathing, seek veterinary care immediately.

Mast Cell Tumors

Dogs suffering from cancerous mast cell tumors are likely to develop frequent chronic inflammation due to excessive blood histamine levels. Your vet may recommend an antihistamine such as Claritin to help provide relief, but keep in mind it will not treat the tumor. Speak with your vet before giving Claritin to your dog, especially if they have a tumor and/or are receiving other medications.

Vaccination Reactions

Vaccines are very important for preventing disease in your pup, and as a vet, I always recommend staying up to date with vaccines. As with humans, some dogs can experience a vaccine reaction, which is basically an allergic reaction to a vaccine, and these reactions can range from mild to severe. Your vet may recommend an antihistamine such as Claritin prior to vaccine administration, although Benadryl is usually chosen. Even though these allergic reactions can be scary, they shouldn’t deter you from administering vaccines to your dog.

The recommended dose for Claritin is 0.2 milligrams per pound of body weight every 12-24 hours. This is only a general recommendation, and as with all medication, you should consult with your veterinarian and have them give you the appropriate dose for your individual dog. Always check the packaging, but typically a Claritin tablet is 10 milligrams per tablet.

As with any medication, giving the correct dose is of utmost importance in order to avoid overdose or toxicity.

Side Effects of Claritin For Dogs

Unlike traditional antihistamines, Claritin doesn’t usually cause drowsiness or hyperactivity. That said, your dog might show the following side effects after ingesting Claritin.

  • Stomach upsets
  • Decreased tear production
  • Dry mouth
  • Vomiting
  • Diarrhea
  • Urinary retention

The side effects are usually not lethal, and should resolve after some time. Symptoms of Claritin overdose include hyperactivity, depression, and/or rapid heart rate.

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Is Claritin Safe for All Dogs?

While Claritin for dogs is commonly prescribed for allergy relief, it can be fatal for pets suffering from certain conditions or currently on other drugs. Loratadine formulations shouldn’t be given to:

  • Young puppies
  • Nursing and pregnant females
  • Dogs ailing from liver, kidney, and keratoconjunctivitis sicca disease
  • Loratadine sensitive or allergic dogs
  • Dogs on other contraindicated drugs such as cimetidine antacid, erythromycin antibiotics, or ketoconazole antifungal drugs

Bottom Line On Giving Claritin To A Dog

Claritin for dogs may be safe when given at the correct dose, but should only be given after speaking to your vet.

Stop treatment and call your vet when you notice any adverse side effects after giving Claritin to your dog.

Tiffany Ruiz Dasilva, VMD, cVMA

Dr. Tiffany Ruiz Dasilva is the Professional Services Veterinarian here at Wild Earth. She received her Bachelor of Science degree in Biology from Brown University, and attended veterinary school at the University of Pennsylvania School of Veterinary Medicine. Since graduation, she has worked in general practice, on telehealth platforms, and in animal rehabilitation. She has worked tirelessly to gain expertise in the field of canine nutrition through numerous certifications and coursework, and plans to pursue her Masters in Animal Nutrition.

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