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Zyrtec For Dogs – For Allergy Prevention

Is Zyrtec Safe For Dogs? The Complete Guide

Zyrtec is an over the counter antihistamine developed for use in humans to treat the symptoms of allergies. However, veterinarians often prescribe it for dogs suffering from skin conditions caused by allergies, as it is generally considered safe and moderately effective for most canines.

Before administering this or any other medication to your pup, you should consult with your veterinarian. It is important that you have some basic information about the use of this drug, potential side effects, and risks.

You should never self-diagnose and treat your dog with medication, even when it is available over the counter. This is especially true with skin problems. Itchy skin is a symptom of many possible conditions and only your veterinarian can rule out potentially life-threatening conditions that demand immediate treatment.

This article is intended to give you the information you need to be an informed patient advocate for your canine so that you can talk to your vet about specific treatment options.

WARNING: Never give your dog Zyrtec-D

Zyrtec has the primary active ingredient cetirizine. Cetirizine has been tested on dogs and has been deemed safe, with some exceptions we will look at later in this article.

It is absolutely critical that you do not administer Zyrtec-D to your canine!

Zyrtec-D contains the decongestant pseudoephedrine which can be deadly to dogs, even in very small doses. This can cause liver or kidney failure in canines and it is absolutely never safe to give your pup.

If your dog has ingested Zyrtec-D, then call the ASPA Animal Poison Control Center hotline at (888) 426-4435 immediately.

If you are looking for generic versions of Zyrtec, it is very important that you read the label carefully. Cetirizine needs to be the only active ingredient for this treatment to be a safe option for treating itchy skin in canines.

What Conditions Does Zyrtec Treat For Dogs?

Veterinarians may recommend Zyrtec for Dermatitis (dry, itchy, irritated skin) related to various allergies.

Symptoms may include:

  • Excessive itching
  • Pawing on the face
  • ​Minor swelling of affected areas
  • “Hot Spots” or areas where your pup has chewed or licked away fur
  • Excessive licking or chewing on the paws or legs
  • Scaly or irritated skin
  • Hair loss in affected areas

Examples of possible allergens include:

  • Certain food ingredients
  • Flea or tick bites
  • Mosquito or mite bites
  • Contact with certain plants such as poison ivy or poison oak
  • Inhaled allergens like pollen or mold
  • Hypersensitivity to certain medications or ingredients in shampoos or lotions

Often Zyrtec will be tried only after other antihistamines, such as Benadryl, have failed to arrest the symptoms of allergy related Dermatitis.

One advantage that it has over other antihistamines is that it usually doesn’t have the side effect of drowsiness often associated with similar medications.

Zyrtec is not an effective course of treatment for all skin conditions. Moreover, it treats symptoms, not causes. This is why it is important to consult with a veterinarian before administering this drug.

If your dog is suffering from itchy skin, your vet may want to do some tests to try to find the causes. It is likely they will want to do an allergy test to see if they can identify the specific triggers for your canine’s allergic response. They may also want to run other tests to rule out different underlying causes.

If specific allergy triggers can be easily avoided, such as a certain food ingredient, then management is usually a better treatment option than drugs.

On the other hand, allergies to environmental agents like pollen or mold can be difficult to avoid, in which case your vet may recommend immunotherapy or treatment with antihistamines.

How Effective is Zyrtec At Treating Itchy Skin & Allergies In Dogs?

The answer to this question is complicated and depends on a variety of factors.

The use of cetirizine, the active ingredient in Zyrtec, has had mixed results in clinical trials for use in the treatment of atopic dermatitis (a chronic skin condition). It may come down to individual differences in the canine regarding the effectiveness of this course of treatment.

Some veterinarians have argued that the chances of antihistamines significantly helping to relieve symptoms of allergy related skin itchiness is about 50%. Some medications may work better than others in your dog. Expect some trial and error when working with your veterinarian to find the right course of treatment for your itchy pup.

Zyrtec For Dogs. What Are The Recommended Dosages

The recommended dosage in canines is 0.5 mg of cetirizine per pound.

For example, if your dog weighs 50 pounds:

0.5mg X 50 lbs = 25mg cetirizine

Of course, the drug does not come in those specific of dosages, so the above calculation is for estimating only. In fact, the safe dosage range for this medication is fairly wide. Some vets recommend that dogs who weigh less than 10 pounds can receive up to a half of a 10mg tablet, while dogs over 10lbs can safely have one full 10 mg tablet daily.

This dosage can be administered once or twice a day depending on the severity of the problem and the specific causes. It is important to work in consultation with your vet so they can track the effectiveness of the drug, and recommend if the dose should be increased or decreased.

Are There Side Effects For Dogs That Have Taken Zyrtec?

Most canines will not experience noticeable side effects with Zyrtec. However, call your veterinarian if any of the following symptoms occur:

  • Severe drowsiness
  • Inability or unwillingness to urinate normally
  • Heavy salivating
  • Vomiting
  • Constipation
  • Loss of appetite

When Should I Not Use Zyrtec To Treat My Dog’s Dermatitis?

There are several cases when using Zyrtec is not recommended, even potentially dangerous:

  • Liver or Kidney problems. If your dog has a history with or is currently dealing with liver or kidney problems, Zyrtec is not recommended. It could make either condition much worse.
  • Known sensitivity to other antihistamines. If your pup has already shown a sensitivity or negative reaction to other antihistamines, there is a good chance that Zyrtec will be a problem too.
  • Pregnancy. If you dog might be pregnant, Zyrtec or any other medications must be administered under the careful supervision of a veterinarian. Although not known to cause gestational issues, it is none the less smart to be on the safe side if your canine is pregnant.
  • Nursing. Nursing canines should not be given Zyrtec as it has been shown to show up in mother’s milk.
  • Other medications. If your dog is receiving other medications then there are possible drug interactions that could be serious. Consult a vet.
  • Other known conditions. If your pup has other known health issues, then it is always advisable to work closely with your veterinarian to make sure Zyrtec or other medications will not exacerbate those conditions.


Itchy skin is a symptom, not a cause. Sometimes the trigger is allergies, in which case antihistamines such as Zyrtec may be recommended as a part of a treatment plan recommended by your veterinarian.

However, some other causes of skin irritation such as hormonal imbalances or underlying immune system problems need a different treatment plan. Prematurely treating itchy skin before such diagnosis have been ruled out may mask important warning signs that your dog may need a different course of treatment.

Lastly, giving zyrtec to your dog should always be in consultation with a Vet.

Sharon Elber (M.S. in Science & Technology) – Professional Dog Trainer

Sharon is a professional dog trainer with over 10 years experience. She is also a professional writer that received her M.S. in Science & Technology Studies from Virginia Tech.For more info on Sharon click here

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One Comment

  1. Hello… My Westie, now age 14, was started on Apoquel 3 yrs ago for itchy skin. Started out twice a day for a week, then 1 a day. Over the last 3 years she only needed it seasonally, once a day. This past August 2019 it didn’t seem to help calm her itching as well in the past. I asked my vet if I should try twice a day for a week, he agreed. Starting on a Monday (August 5th) she had one twice a day. The following Thursday (Aug 8th) she had just the one in the morning. Later that day she suffered what seemed to be a small seizure. Her body was tense and tightened up, and she couldn’t turn her head to look at me as she tried. It only lasted maybe 35 seconds as held her close and spoke to her calmly. Then an hour later, as she tried to stand up she fell against the couch, once again body tightened up, lasted under a minute. I stopped the Apoquel all together. Next day Told my vet about this, and he called his Apoquel rep and of course they said they were very sure it was not the Apoquel. But my Westie has not had a single one since or anything similar, it’s been well over a month now. She just had her yearly check up, other than her itching problem she is doing well for her age.
    So .. I was wondering if it was possible for you to find out if there has been any other similar incidents involving other dogs on Apoquel. I’ve done some searches but found very little documented info. I was told by a friend that she saw a few people complaining about Apoquel on Facebook, but had no details. Thank you in advance for any help

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