Zyrtec for Dogs Allergies: Safety, Recommended Dosage, and Precautions


Dogs are similar to humans in so many ways. Like us, our pets are vulnerable to allergies, their bodies can negatively react to certain substances. Most canines develop allergies between birth and three years of age, although for some this can happen at a later age.

Can I Give My Dog Zyrtec?

Most dog owners give their pet human meds to put an end to any symptom of hypersensitivity. One of the most known and vet-approved human meds for them is Zyrtec.

What does Zyrtec contain that it was deemed safe for pets? How will you know it’s time to give your pet this drug?

In this post, we will try to answer everything you’d like to know about antihistamines for dogs. But before that, it’s important to be aware of canine allergies. This way, you’ll know what else to do, besides giving Zyrtec, in case your pet suffers from them.

What triggers our pets’ allergies?

There are so many foreign protein substances that could contribute to your pet’s allergy. Did you know that for us humans, there are more than 300 kinds of irritants out there? Here are the most common irritants among canines:

  • Flea bites – the hypersensitivity to flea bites is the leading type of aversion among dogs. The skin allergy or flea bite dermatitis comes from those small insects that thrive on their bodies. You will know your pooch is suffering from flea bite dermatitis when he starts having hot spots that look extremely itchy. Your pet may start itching especially on the flea-prone body parts such as his feet, ears, and eye area.
  • Atopy – also known as inhaled allergies, it may come from dust mites and mold spores. Sometimes, your pet could even get it from grass pollen, or from hay in our backyards. During spring, dogs may get worse allergies due to the pollen.
  • Foods –the common culprits for canines are beef, chicken, soy, and wheat. In most cases, pets do not immediately show symptoms after introducing a new food. Thus, vets need to conduct a food elimination process in order to identify the culprit.

What are the symptoms of dog allergies?

Dogs may show one or two symptoms of allergies. Take note of these red flags:

  • Itchy or red skin – this refers to severe itching that can make your dog shed more than usual. It’s either your doggie is just going through skin problems or it’s already allergy. Unlike us, who absorb allergens by inhaling them, canines get theirs through their skin, so itching is the most common symptom of dog allergy.
  • Runny eyes – there are various types of eye discharge in canines and they mean different things. When your pet starts having watery or runny eyes, this could be a sign that he is having some sort of allergies. If your pet is showing signs of discomfort alongside eye discharge, you have to monitor him or tell your doctor right away.
  • Sneezing – like us, our pets also normally sneeze. But if it’s already reverse sneezing or gagging then it could be due to hypersensitivity to certain objects or foods.
  • Constant licking – this is characterized by nonstop licking on certain areas of his body. Usually, that spot has brown discoloration. You could also see him incessantly rubbing parts of his body on a carpet or furniture.
  • Digestive issues – observe your pet’s bowel. Is he having a bad case of diarrhea? Has he started vomiting more frequent than the usual? If this is the case, let your vet know.
  • Heavy snoring – this is another human characteristic that is present among canines. They normally snore and that’s for a number of reasons. One of those reasons is probably because of an underlying hypersensitivity or allergy.

How does Zyrtec work?

Now that we’re done introducing allergies and their warning signs, it’s good to know how antihistamines really work inside a canine’s body. As far as your pet’s health is concerned, it is crucial to be educated in the medicines and treatments you give him.

Zyrtec is a brand of cetirizine, a type of antihistamine that is commonly used by people. You can buy it over-the-counter. Yes, you don’t need any prescription from your vet because it is also safe for canines. However, do note that you may give your pet Zyrtec as long as it does not contain Decongestant.

You must not give your pet “Zyrtec- D” because it has pseudoephedrine that could cause seizures. In case the dog accidentally ingested any antihistamine drug with Decongestant, bring him to a veterinarian immediately especially if his heart rate started to beat faster than the usual. When ingested, the Antihistamine with Decongestant can make your pet anxious. It is best to seek for a veterinarian’s help if he has not returned to his usual state in 24 hours. You will know your dog has had an overdose of the med if he started showing unusual behaviours.

Just like how you would normally take any medication, do not increase your dog’s dosage. Likewise, don’t give the medicine to your pet more often than recommended. Your vet is the only one that has the authority to increase or decrease the dosage. That will heavily depend on how bad the allergy is or if the pet is actually showing signs of relief.

How much Zyrtec can you give a dog?

Zyrtec comes in tablet form. The recommended Zyrtec dog dosage depends on two things. The first one is your pet’s weight and the other one is the condition of them.

Here are the recommended dosages of Zyrtec for canines:

  • Dog weighing 0-15 lbs (up to 6.8 kg): 5 mg/per day
  • Dog weighing 16-39 lbs (around 7-17 kg) : 10 mg/day
  • Dog weighing more than 40 lbs (above 18 kg) : 10 mg 2x a day

Small dog breeds like Cavalier King Charles Spaniel, Chihuahua, Cairn Terrier, Miniature Dachshund, Pomeranian, and Italian Greyhound should not be given more than 5 mg of Zyrtec per day.

Small to medium-sized dogs such as Poodle, Portuguese Water Dog, Shiba Inu, Soft Coated Wheaten Terrier, and Whippet may take as much as 10 mg but only once per day.

Big dog breeds like Saint Bernard, Siberian Husky, English Springer Spaniel, and Rhodesian Ridgeback can be given Zyrtec twice a day.

What are the side effects of Zyrtec in canines?

As an antihistamine, Zyrtec may make your pet drowsy. Some dogs also experience fatigue after ingesting the drug. However, the side effects may differ from dog to dog. Others may also experience dizziness, blurry vision, and loss of appetite.

Unfortunately, antihistamines can also cause diarrhea. Observe how your dog reacts to the medicine. In rare cases, this drug can also make the dog bark excessively and may cause problems when urinating. You will eventually notice certain changes to your dog, like becoming too excited or anxious.

What else you need to know about allergies and antihistamines?

  • Your vet will conduct a proper diagnosis to identify if the symptoms were really due to allergy. The thing is, it is not that easy to determine allergies among canines. Once the preliminary diagnosis has been conducted and your pet doctor has not identified the culprit, he will then conduct a series of other exams. One of the tests is the intradermal skin testing to identify the allergen. The vet may also conduct a blood test.
  • Consider mild and natural treatments to help your pet feel better. If your pooch has some hot spots all over his body, you may use coconut oil and apple cider vinegar mixed with water for an instant relief. There are also mild antiseptics that you can purchase in spray form. You may apply topical or ointments prescribed by your vet.
  • Ask your vet about allergy shots – hypo-sensitization or allergy shots for dogs are being done to sensitize your pup’s body to certain irritants. Vaccines work on canines the same way they work on humans. However, they are not very common among canines because the shots are quite expensive and experts still continue to weigh in their potential side effects. Nonetheless, you may still ask your pet doctor about this, if you are interested.
  • Don’t give your dog more than the recommended dosage of the antihistamine. Too much of antihistamines can poison your puppy. When untreated, it can badly affect your pet’s central nervous system and worse, cause cardiovascular irregularities.
  • Antihistamines like Zyrtec may or may not work for your pet. They are only effective in 30% of canines. There is such a thing as antihistamine hypersensitivity as well.

You can become a more responsible dog parent by keeping your environment clean. It is important that our pets’ beddings are cleaned frequently. Make sure there are no fleas or ticks thriving on your dog’s body. Your pet also needs frequent baths. Bathe him yourself or bring him to a groomer at least once a month. If he has an oily coat depending on his breed, you might need to bathe him at least once a week

There you have it! Has your pet suffered from an allergy before? What did you do to make him feel at ease? If you have given Zyrtec to your pet before, let us know how it worked for him. Was it effective in relieving your dog’s allergy? We would love to hear your thoughts.


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