Zyrtec For Dogs: Dosage, Side Effects And Everything You Should Know

Zyrtec is a brand name for cetirizine hydrochloride, a relatively new available over-the-counter antihistamine that’s commonly prescribed by veterinarians to help cure common allergies that affect dogs.

Many veterinarians prefer to use Zyrtec only when Benadryl doesn’t lead to any improvements in the dog’s condition.

Cetirizine is mainly intended for human use and not animal use, despite the fact that many veterinarians prescribe it to dog patients who have certain types of allergies.

Which brings us to the question, is cetirizine, or Zyrtec as we will be referring to it from now on in this article by its brand name, safe for dogs?

Is Zyrtec For Dogs Safe?

In short, YES, Zyrtec is safe to use on dogs, on one condition though, and that is that you follow all the rules and proper dosages that apply.

We will get to that in just a bit, though.

What Does Zyrtec Do For Dogs?

Usually, the most common problems that veterinarians refer to Zyrtec to treats in dogs are skin problems that mostly show on dogs between the age of 1-3 years, among which are:

  • Dermatitis: Where your dog’s skin becomes very itchy.

If your dog has skin allergies that needs something like Zyrtec to solve, you will see some or all of these symptoms in your canine:

  • Skin itchiness and irritation that leads them to scratch
  • Excessive face rubbing
  • Hair loss
  • Swelling in various skin areas
  • Excessive head shaking
  • Excessive chewing of body parts like paws or legs
  • Excessive licking

If you see any of these symptoms in your dog, you have to immediately get them to professional animal care, because if left untreated, your dog could develop potentially life-threatening diseases.

The One Zyrtec Form You Should ONLY EVER Give To Your Dog

You MUST make sure that the formulation of Zyrtec you give to your dog has only one active ingredient, which is cetirizine.

Other formulations out there, most common of which is “Zyrtec-D”, contains other very deadly ingredients to dogs such as pseudoepehedrine, and should never be given to dogs.

So, make sure you carefully read the active ingredients on the product packaging before you give it to your dog as treatment, and make sure you NEVER EVER give “Zyrtec-D” to your dog.

Some studies show very scary numbers regarding “Zyrtec-D”, such as finding that as little as two tablets could be enough to kill a small sized dog.

Zyrtec Dosage For Dogs

Before we kick off this section, please note that any of these dosages are scientific estimates at best.

You should always consult your veterinarian before you start a course of treatment for your dog with this medication or any other, as they will tell you the exact dosage you should give your dog and all other details you should know.

Generally, cetirizine is taken orally, in a tablet form, once a day. The required dosage is mostly determined by your dog’s weight.

The standard recommended Zyrtec dosage for dogs is:

  • Dogs over 10 lbs: Give one 10mg tablet once daily
  • Dogs under 10 lbs: Give one-half of a 10mg tablet once daily

You can feel free to give Zyrtec to your dog alone or with some food, whatever works best for them.

If you suspect that your dog has overdosed on Zyrtec, immediately contact your veterinarian so they tell you the necessary steps you have to do.

When Is Zyrtec Not Safe For Dogs?

Here’s a list of some of the circumstances where you should be extra careful about giving your dog Zyrtec:

– Liver Or Kidney Problems: Giving your dog Zyrtec if they’re known to have liver or kidney problems can be very dangerous, mainly because it can cause urine retention and worsen either situation, so you have to consult with your veterinarian first to determine the severity of the issue

– Hypersensitivity: Some dogs are known to be hypersensitive to antihistamines, in which case they should not be administered any Zyrtec.

– Pregnancy: There are not sufficient studies that show that Zyrtec is safe to be given to dogs which are pregnant, so be extra careful on this one

– Nursing: Nursing dogs can pass some Zyrtec in the milk they give to their puppies, so they shouldn’t be given any during this period

Zyrtec Side Effects On Dogs

Here are some of the most common side effects that dogs which are administered Zyrtec could show:

  • Vomiting
  • Hyper-salivation
  • Drowsiness (although this one usually fades away by itself as your dog gets accustomed to the medicine)
  • Heavy sedation
  • Constipation
  • Retention of urine

If your dog shows any of these symptoms, stop giving them Zyrtec and let your veterinarian know about the situation so they determine whether a dosage modification is required, or the prescription of another antihistamine all together.


  1. PLEASE double check the information you have given here on dosage. You said .5mg PER POUND for a dog. This could very easily lead someone to overdose their dog, potentially killing it!!! Shoot, as a HUMAN over 200#s even I only take ONE 10mg tablet per day!

    The standard recommended Zyrtec dosage for dogs is:
    Dogs over 10 lbs: Give one 10mg tablet once daily
    Dogs under 10 lbs: Give one-half of a 10mg tablet once daily

  2. My dog’s kidney numbers were higher than normal in a blood test. Should I be concerned if the vet prescribed 5mg Zyrtec daily for skin allergies


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