Treating dogs with food allergies and skin conditions is a frustrating and exhausting process. Dog owners are constantly looking for the best treatment options, including prescription and over-the-counter antihistamines.

Dog allergies can affect pets of all ages. Their symptoms range from mild to severe and depend largely on the allergen. Itching, diarrhea, difficulty breathing, and wheezing are common reactions.

This post covers everything you need to know about Zyrtec for dogs including dosage, safety, uses, and side-effects.

Is Zyrtec Okay for Dogs?

Veterinarians often prescribe Zyrtec for dogs with allergies. Unlike Benadryl, this medication is less likely to make your pet drowsy. Additionally, it only requires one daily dose. Zyrtec is also prescribed to humans. Even children can use it. But is Zyrtec okay for dogs?

As it turns out, this popular drug might one of the safest pet antihistamines. WARNING: Do not use the Zyrtec-D formula for dogs. That particular medication includes pseudoephedrine which can cause toxicity in pets.

Why Use Zyrtec for Dogs?

Zyrtec has emerged as a safer, more effective alternative to Benadryl and other H1 antagonists. Its generic name is cetirizine, but it’s sold under several brand names. Like Benadryl, it relieves allergic reactions in pets, including watery eyes, sneezing, itching, and inflammation.

A study published in The Canadian Veterinary Journal assessed the effects of Zyrtec on canine atopic dermatitis, the second most common cause of allergic skin disorders in dogs. As the researchers note, this condition affects up to one-third of our canine companions. Approximately 18 percent of the dogs treated with Zyrtec experienced relief from pruritus, the primary symptom of atopic dermatitis.

Additionally, the drug was well-tolerated and had negligible side effects. Only two dogs experienced mild adverse reactions, such as vomiting and increased salivary volume.

Other pet antihistamines, including doxepin, cyproheptadine, and terfenadine, produced more frequent adverse reactions in clinical trials. Cetirizine, on the other hand, appears to be safe.

A major advantage of using Zyrtec for dogs is that it requires a single daily dose. Other antihistamine products require at least two or three doses per day to produce noticeable results.

What is the Correct Zyrtec Dosage for Dogs

To find the correct Zyrtec dosage for dogs it’s important to get your dog’s current weight. Generally, the recommended dose is 0.5 mg/lb or 1 mg/kg once a day. Always follow your veterinarian’s advice above and beyond what you read here.

Are There Any Side Effects in Zyrtec for Dogs?

Most medications carry side effects. Zyrtec is no exception. Although this drug is safer than other antihistamines, it may still cause adverse reactions, including:

  • Excessive salivation
  • Urine retention
  • Nausea and vomiting
  • Constipation

Furthermore, Zyrtec is not recommended to dogs with liver or kidney problems as it may worsen their symptoms. Most side effects are rare, though. Just make sure you stick to the recommended dose.

What Causes Allergies in Dogs?

Several types of antihistamines for pets exist, and each has a different mechanism of action. Choosing one depends largely on what caused an allergic reaction in the first place. Like their human companions, animals can develop allergic to various foods and substances. Some are born with allergies, while others develop them later in life.

Allergies occur when the immune system overacts to foreign scents, food ingredients, and so on. When your pet is exposed to allergens, his immune system begins to release histamine. This compound triggers inflammation, itching, edema, and other symptoms.

The same happens in humans, so we’re not that different from our furry friends from this perspective. That’s why most antihistamines will work for both humans and pets, but at different dosages. When determining the best zyrtec dosage for dogs, consult with a veterinarian.

Dogs can develop different types of allergies, depending on the substance that triggers an immune reaction. These include allergic dermatitis, or skin allergies, food allergies, and acute allergic reactions.

Skin allergies, for instance, can be caused by fleabites, environmental allergens, or certain foods. If your dog is allergic to flea saliva, he may experience itchiness, skin redness, and swelling, among other symptoms. Itchy skin is also a symptom of food allergies and sensitivities.

Acute allergic reactions are by far the most dangerous. Some dogs may have severe reactions to vaccines, bee stings, or other allergens and enter anaphylactic shock. This life-threatening condition requires emergency care.

How Do Pet Antihistamines Work?

Antihistamines are the first-line of treatment for allergies in both pets and humans. Older formulas caused drowsiness, memory problems, sleepiness, fatigue, and poor mental focus. The latest types of antihistamines are safer and more effective.

These medications come in tablet, cream, syrup, capsule, and spray form, so they’re easy to administer. In general, they’re recommended for short-term use.

The main types of antihistamines for pets are H1- and H2-antihistamines. The former bind to histamine H1 receptors in certain tissues and may help relieve allergic reactions affecting the respiratory tract. These are usually prescribed for sneezing, itching, and runny nose.

H2-antihistamines work by binding to histamine H2 receptors in the digestive tract. These medicines may help treat acid, reflux, stomach ulcers, and other gastrointestinal conditions.

The first types of antihistamines are the ones prescribed for allergies. By acting on the H1-receptors, they help reduce inflammatory responses and provide relief from allergic reactions. Both Zyrtec and Benadryl are classified as H1 antagonists.

Not too long ago, vets prescribed Benadryl for dogs and other animal companions. Although it’s effective, it may cause sleepiness and drowsiness. These side effects are due to diphenhydramine, its primary compound.

This medication isn’t approved for veterinary use by the FDA. However, when using the correct Zyrtec dosage for dogs, it’s generally safe for most pets with mild-to-moderate allergies. It is effective at relieving hives, itching, sneezing, redness, swelling, and other allergic reactions.

This dog could use a safe Zyrtec dosage for dogs to stop that itch.
dog sitting and scratching itself on the grass

Keep Your Dog Allergy-Free

Allergies can be just as devastating for pets as they are for their human companions. Don’t make any compromises when it comes to the health of your beloved friend. Consider using Zyrtec for dogs to keep him allergy-free and prevent complications.

Always consult a veterinarian before giving pills or supplements to your pet.

Some dogs are hypersensitive to Zyrtec and other antihistamines, so don’t take unnecessary risks. Also, beware that this medication can interact with other drugs or worsen existing conditions.

If your furry friend is vomiting, he may have an allergic reaction or something more serious. Some medications can help. Check out our guide to giving your dog Pepto-Bismol for vomiting!

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The Canadian Veterinary Journal 2004 May 1; 414-417

Scott DW, Miller WH Jr, Griffin CE. Muller & Kirk’s Small Animal Dermatology VI. Philadelphia: WB Saunders, 2001:543–666.


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