Cetirizine for Dogs

Molly Price, DVM
By Molly Price, DVM on Nov. 20, 2023
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PetMD’s medications content was written and reviewed by veterinary professionals to answer your most common questions about how medications function, their side effects, and what species they are prescribed for. This content shouldn’t take the place of advice by your vet.

What Is Cetirizine?

Cetirizine is an over-the-counter anti-allergy medication for humans. It is used to manage symptoms of seasonal allergies (atopy) in dogs and is sometimes used in cats for itching and in horses for eosinophilic keratitis, an inflammatory eye condition.

Cetirizine is FDA-approved for human use under the brand name Zyrtec®, Zyrtec-D® (the “D” indicating the “decongestant” as this product contains pseudoephedrine) and as generic cetirizine.

Cetirizine is available in a wide variety of products, including single-ingredient tablets, combination-ingredient tablets, chew tabs, gel caps, oral syrup, and orally disintegrating tablets. It is important to note that Zyrtec-D®, the combination product containing pseudoephedrine, is not safe for use in dogs or cats. Some liquid formulations may contain propylene glycol, which is toxic to cats. The orally disintegrating tablets may contain xylitol, which is toxic to dogs.

Cetirizine is currently not FDA-approved as a veterinary medication. However, it is readily utilized in the veterinary field, and veterinarians can legally prescribe certain human drugs in animals in certain circumstances. This is called extra-label or off-label use because this use isn’t described on the drug label.

In certain circumstances, your vet may recommend a compounded formulation of cetirizine. Compounded medications are prescribed if there’s a specific reason your pet’s health can’t be managed by an FDA-approved drug, such as if your pet has trouble taking pills in capsule form, the dosage strength is not commercially available, or the pet is allergic to an ingredient in the FDA-approved medication. Compounded medications are not FDA-approved. They are created by either a veterinarian or a licensed pharmacist on an individual basis to best suit a patient’s particular needs. You can learn more about compounded medications here.

Cetirizine Considerations

Cetirizine should not be used in animals that are sensitive to the medication or other medications in the same antihistamine class, such as hydroxyzine. Giving cetirizine with certain medications can result in health risks to your pet, so it is important to discuss your pet’s medications, including vitamins and supplements, and medical conditions with your veterinarian.

How Cetirizine Works

In response to the presence of certain allergens (foreign proteins), the immune system releases histamine, a chemical messenger that triggers allergy symptoms. As an antihistamine, cetirizine works by blocking histamine receptors, thereby preventing the release of histamine throughout the body.

Cetirizine Directions

Follow the directions on the drug label or as provided by your veterinarian.

Cetirizine can be given with or without food, but giving it with food can decrease the risk of digestive upset.

Missed a Dose?

Speak with your veterinarian about what to do if you forget to give a dose of cetirizine. Generally, they may instruct you to give it when you remember, or if it is almost time for your pet’s next dose, to skip the missed dose and resume your normal dosing schedule. Do not give extra or double doses.

Cetirizine Possible Side Effects

Cetirizine is generally well tolerated in animals. Side effects are uncommon and may include:

  • Vomiting

  • Drooling (hypersalivation)

  • Sleepiness

Human Side Effects

Cetirizine is a medication for humans, frequently with dosages different from those prescribed for your pet by a veterinarian. Due to possible side effects, humans should never use medicine dispensed for their pets and pets should not be given any medicine dispensed for a human’s use.

If you accidentally ingest a pet medication, call your physician or the national Poison Control Center hotline at 800-222-1222.

Call Your Vet If:

  • Severe side effects are seen (see above)

  • Your pet’s condition worsens or does not improve with treatment

  • You see or suspect an overdose

  • You have additional questions or concerns about the use of cetirizine

Cetirizine Overdose Information

Overdoses of cetirizine are rare. Signs of a cetirizine overdose may include hyperactivity, agitation, vomiting, sleepiness, dilated pupils, diarrhea, and elevated heart rate (tachycardia).

Overdoses of cetirizine products that contain pseudoephedrine, such as Zyrtec-D® may be serious.

If you suspect an overdose, immediately contact your veterinarian, seek emergency veterinary care, or call an animal poison control center. Consultation fees often apply.

Pet Poison Helpline (855) 764-7661

ASPCA Animal Poison Control (888) 426-4435

Cetirizine Storage

Always confirm storage requirements by reading the prescription label.

Cetirizine should be stored at controlled temperatures from 68 to 77 F.

Keep the container tightly closed in order to protect its contents from moisture and light. Compounded medications should be stored according to the compounding pharmacy’s label.

Keep out of reach of children and pets.

Cetirizine for Dogs FAQs

Is cetirizine safe for dogs?

Cetirizine is considered safe for most dogs. Speak with your vet first to ensure this medication is appropriate for your dog. It is important to only use products that contain cetirizine as the sole active ingredient and avoid human combination products that contain other ingredients that may be toxic to animals.

Zyrtec-D®, the combination product containing pseudoephedrine, is not safe for use in dogs or cats. Some liquid formulations of cetirizine may contain propylene glycol, which is toxic to cats. Cetirizine orally disintegrating tablets may contain xylitol, which is toxic to dogs.

Can dogs take cetirizine for allergies?

Yes. Dogs can take antihistamines including cetirizine for relief from allergy symptoms.

How much cetirizine can you give a dog?

With any medication, the safest way to know the proper dose for your dog is to ask your veterinarian. Your veterinarian will recommend the appropriate dose for your dog depending on their individual needs, other medications they may be on, and their age, weight, and breed.

No vet writer or qualified reviewer has received any compensation from the manufacturer of the medication as part of creating this article. All content contained in this article is sourced from public sources or the manufacturer.

Featured Image: Antonio_Diaz/iStock via Getty Images Plus


Cook CP, Scott DW, Miller WH, et al. Treatment of canine atopic dermatitis with cetirizine, a second-generation antihistamine: a single-blinded, placebo-controlled study. Canadian Veterinary Journal. 2004;45:414-417.

Hsiao YH, Chen C, Willemse T. Effects of cetirizine in dogs with chronic atopic dermatitis: a randomized, double blind, placebo-controlled trial. Journal of Veterinary Science. 2016;17:549-553.


Molly Price, DVM


Molly Price, DVM


Dr. Molly Price has practiced small animal medicine for over 20 years and is a graduate of Texas A&M College of Veterinary Medicine. She...

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