Zytrec for Dogs: A Word of Warning

By Chelsea Hunt-Rivera / November 6, 2018
zyrtec for dogs

Did you know dogs can get allergies just like us? Dogs can be allergic to anything from environmental factors like local pollen and grass to ingredients in their food and treats. When people and animals are suffering from allergies, vets prescribe antihistamines like Zyrtec. While vets commonly recommend Zyrtec for dogs with allergies, it can have some severe side effects. Before using Zyrtec for dogs, read about the possible side effects and learn about the alternatives, including natural remedies.

Dog allergies can have many different causes. Unfortunately, it’s hard to treat your dog for allergies if you do not know the source of the issues. The easiest treatment is elimination and avoidance. With that said, seasonal allergies or common environmental allergies like dust or pollen can be a little more difficult to avoid. You can use specific methods like wiping your dog down with a natural wipe before coming inside and using an air purifier to minimize the allergens in your home. If you’ve exhausted all options and can’t get rid of the allergens, an allergy medication like Zyrtec could provide relief. However, it doe come at a price. Continue reading to find out what we mean.

zyrtec for dogs

What is Zyrtec?

Zyrtec is a popular over-the-counter medication that alleviates the symptoms of allergies. It is classified as a second-generation antihistamine. When exposed to an allergen, the body produces histamines. The result leads to itching, hives, itching, watery eyes, and sneezing. Antihistamines stop or reduce the histamines, which get rid of the allergy symptoms. First generation antihistamines are great for preventing motion sickness or treat ear infections but they come with a drowsy side effect. For example, a few first-generation, over the counter antihistamines that you probably know of are Benadryl and Dramamine. However, since pet owners do not want their dogs to be tired all of the time, second-generation antihistamines are used as a daily allergy treatment for pups!

Zyrtec Ingredients

The main ingredient in Zyrtec is cetirizine, which is an antihistamine. Since Zyrtec is a non-drowsy antihistamine, many veterinarians recommend it for pet allergies. Cetrizine doesn’t cross the blood-brain barrier, allowing it to stop histamine without the side effect of tiredness. While Zyrtec is not FDA approved for animal allergies, veterinarians typically consider it suitable for animals.

Zytec works best for allergic dermatitis, or skin-reactions from allergies. It also works for dogs that get itchy (pruritus) hives, hot spots, rashes, and other skin-related symptoms from environmental allergies.

What is Zyrtec D?

It is important to remember that Zyrtec is designed for human use. In people, it can be helpful to treat multiple symptoms zyrtec for dogswhen we are unwell. However, dogs are more sensitive to drugs than we are. This is why it’s important to read all of the ingredients when giving your dog an over-the-counter medication. All Zyrtec is not the same. There are different formulas to treat specific needs. The only Zyrtec you should ever consider giving your dog is the original or the generic that is just Cetirizine.

Zyrtec-D is a formulation of Zytrec that adds a decongestant called pseudoephedrine. This specific type of Zyrtec, along with the generic version, is not safe to use on dogs and cats. In fact, it can be potentially fatal.

When giving your dog Zytrec make sure it is just Cetirizine without any pseudoephedrine. Pseudoephedrine stimulates the nervous system and cardiovascular system. It causes high blood pressure, increased heart rate and other behavioral changes in dogs that can be dangerous.

What is Zyrtec Generic?

The generic form of Zyrtec is cetirizine hydrochloride. Fun fact: FDA approved generic drugs must be the same dosage, strength, quality, and performance as the brand-name drug. Generic Zyrtec must perform in the same ways in the body as the brand name Zyrtec. Rest assured, generic drugs are rigorously tested by the FDA. Additionally, they are only able only to go to market after a specific period.  This is due to patent laws surrounding name-brand drugs. Generic drugs are cheaper because they do not have to complete the same clinical trials on humans and animals that the brand-name drugs did. You can save money by giving your dog cetirizine hydrochloride instead of the brand-name Zytec. Make sure to only get Cetirizine Hydrochloride alone not with pseudoephedrine hydrochloride. It should only be an antihistamine, not an antihistamine/nasal decongestant. The pseudoephedrine is toxic to dogs.

Zyrtec for Dogs

People choose Zyrtec to help treat seasonal allergies and allergic reactions in dogs. Zytrec is non-drowsy, so it is often the zyrtec for dogs allergiesantihistamine of choice for common allergies in dogs. As we know, dogs can get allergies just like humans from common allergens like local plants in bloom or a bite from a flea. Additionally, dogs can have allergic reactions from contact dermatitis and atopic dermatitis which triggers inflammation, itching, swelling, and hives.

As you can imagine, itching and other skin conditions are quite uncomfortable.  The constant itching and licking also lead to an open wound or a dog hot spot. These wounds are susceptible to yeast and bacterial infections. Allergic reactions can get worse over time and start negatively affecting your dogs quality of life. Not to mention, they can become restless and unable to sleep due to the itching.

When a pet has an allergic reaction, it can also cause hives, diarrhea, vomiting, and fascia swelling. If your pet is having an allergic reaction and needs quick care, Zytec takes about an hour to work, other over the counter antihistamines like Benedryl only take 30 minutes.

Zyrtec Dosage for Dogs

It’s important to give your dog the correct dose of Zytrec, whether you’re using the brand name or the generic. Double check that it is only Zyrtec, not Zyrtec-D with pseudoephedrine which once again, is NOT safe to use in dogs. Also, in general, always check with your vet before giving your dog new medication. Typically, the dosage for Zyrtec for dogs is 0.5 mg for every pound of weight, every 12 to 24 hours. Zytrec can be found over-the-counter at local pharmacies. It comes in 10mg tablets.

Zyrtec for Dogs Precautions

As we mentioned before, Zyrtec comes with a price. More specifically, Zyrtec is hard on your pup’s organs. More specifically, Zytrec can be dangerous with dogs that have existing liver or kidney issues. The allergy medication can cause urine retention, which can be damaging if a dog has a pre-existing condition. Additionally, Zyrtec interacts with other drugs. That is why you must make sure your vet knows if your dog is taking Zyrtec before they are prescribed any medications. If your dog is taking other medications, ask your vet before giving Zyrtec to your dog to avoid any potentially harmful drug interactions. Lastly, Zyrtec is not safe for use on pregnant or nursing dogs. Ask the veterinarian before giving Zyrtec to puppies or tiny dogs. If your dog has any pre-existing health conditions like hypercalcemia or is sick, check with the vet before using Zyrtec in case it could make the condition or sickness worse.

Zyrtec Side Effects

Zyrtec is typically safe in healthy dogs. However, sometimes, the side effects can be dire. The most common side effects of Zyrtec are vomiting, constipation, urine retention, and excessive salivation. Dogs with liver and kidney problems could see worsening of these issues, which makes them poor candidates for Zyrtec for dogs.

Dogs can have different reactions to medications just like people can. It’s important to talk to your vet about the correct dosage and monitor them the first couple of times you give it to them. Allergic reactions do not always happen right away. They can progressively get worse as the exposure levels to the allergen increases.

zyrtec for dogs causes salivation

Other Allergy Medicine for Dogs

You can talk with your vet about the allergy medicines available for dogs. Depending on your dog’s specific allergy and its symptoms one allergy medicine may work better for your dog than others. Some other options include:

Allergy Shots

Allergy shots can be useful in dogs with severe allergies. It takes three to six months to start working. After an allergy shot, the dog’s immune system is slowly desensitized by the allergy triggers. Your vet will administer multiple shots per week in the beginning, but the process gradually slows down until only booster shots are needed every few months. Allergy shots can be more convenient for dogs that have allergy triggers that are hard to avoid and for pet owners who do not want to have to give their dog a daily pill. After all, some pups, as precious are they are, can make administering pills a nightmare.


Dogs with severe allergies can find relief with steroids. These anti-inflammatory drugs are powerful and can quickly stop allergy symptoms but are not ideal for long-term use. Steroids can negatively affect the immune stem and cause gastrointestinal issues. It’s not uncommon for dogs taking steroids to drink and urinate more than average.

Zyrtec vs. Claritin

Claritin works similarly to Zyrtec and is also used to treat allergy symptoms in dogs. Like Zyrtec-D, Claritin-D contains pseudoephedrine which is also extremely dangerous for dogs. Only use regular Claritin and the generic on your dog. Claritin can cause drowsiness, urinary retention, vomiting, change in bowel movements, and thirstiness in dogs. Claritin may interact with other drugs, including other antihistamines, and can be dangerous in dogs that have liver and kidney issues. Liquid Claritin can contain a high level of alcohol which can be hazardous for your dog. Talk to your vet before considering Claritin for your dog.

Benadryl for Dogs

Benedryl (Diphenhydramine ) is used to treat dog allergies or to stop an allergic reaction. Unlike Zyrtec, one of the side effects is drowsiness. While it isn’t typically used to treat allergies on a daily basis, Benedryl is great to have on-hand for insect bites, stings, and to prevent vaccination-related reactions. It can also help motion sickness and act as a mild sedative for dogs, so it often used during travel. However, with that said, pets with glaucoma, high blood pressure, and cardiovascular disease should not use Benedryl. Talk to your vet before giving your dog Benedryl to get the correct dosing. If your dog has an allergic reaction that includes facial swelling or difficulties breathing, contact your vet immediately.

Chlorpheniramine for Dogs

Chlorpheniramine is used to treat pet allergies and allergic reactions in dogs and cats. Not to be used on a daily basis, it is moreso used by veterinarians for temporary relief from allergies. It is available in a tablet, liquid, or through an injection. It can interact with other medications and cause other side effects so only use under vet direction.

Atopica for Dogs

Atopica is a prescription medication that also treats skin allergies in dogs. It can be used over long periods of time and is an alternative to steroids. Atopica is also available for cats.

Apoquel for Dogs

Apoquel is used to treat itching and inflammation in dogs due to allergens including flea allergy, food allergy, contact allergy, and atopic dermatitis. It takes less than four hours to work, lasts for 24 hours, and is available through your veterinarian. It can be used alongside other medications like parasiticides, antibiotics, and vaccines. However, Apoquel comes with some unsavory side effects so buyer beware.

What Can I Give My Dog for Allergies: A Natural Approach

Traditional allergy medications from the vet generally come with side effects and are generally not healthy for long-term use. You want to help your dog feel better and stop itching but what is a holistic pet parent to do?!

Luckily, there are many natural approaches to treating dog allergies for pet owners who are concerned with the side effects of common, over the counter and/or prescription allergy medications for dogs. We always encourage pet parents to try natural remedies first to see if it alleviates the symptoms of the allergies before trying Zyrtec or other allergy relief drugs.

Some allergens cannot be avoided, such as trees in bloom or an allergy to grass or dust. It’s important to understand what your dog is allergic to in order to help reduce the symptoms. If you think your dog is allergic to an ingredient in their food, try an elimination diet. Start eliminating certain ingredients from their food and see if the allergy stops. Most often, dogs are allergic to wheat, grains, and certain vegetables. You can avoid food allergies once you discover the allergy. As for other holistic options…

cbd for oils

CBD Oil for Dogs

Made from the hemp plant, CBD oil can help treat dog allergies. CBD naturally reduces inflammation and when combined with other skin-friendly ingredients can reduce itching, rashes, and other problems. It can keep the skin balanced. Honest Paws has created a selection of CBD oil treats and oils that are designed to help dogs with allergies and skin issues. They combine CBD with other healthy oils to help treat the skin issues associated with allergies. The treats are made with high-quality CBD oil and all natural ingredients.

Fish Oil for Dogs

Fish oil is rich in Omega-3 fatty acids, which can help reduce systematic inflammation. You can help treat your dog’s allergies and skin issue from the inside out. Omega-3 fatty acids are also great for reducing inflammation in other parts of the Boyd and help with arthritis, heart disease, and many other health conditions. You can give your dog salmon and sardines in their food or other Omega-3 oils from krill or anchovies. Don’t be surprised if their coat is shinier than ever when eating these healthy fatty acids!

Keep Your Dog Clean

You and your dog could be unknowingly tracking in allergens from outside. Try taking your shoes off before entering your house and wiping your dog’s paws with all natural pet wipes. You can help sooth the skin and remove allergens by bathing your dog regularly (not too much, you don’t want to strip the skin of essential oils) with a gentle and soothing shampoo. Oatmeal is an excellent ingredient for soothing the skin and smells fantastic.

Aloe Vera

Aloe gel is great for treating hot spots and rashes in dogs due to allergies. You can put the gel directly onto the skin. It’s cooling and provides immediate relief. You can use it twice a day on your itchy dog.


Calendula is a triple threat being an antibacterial, antifungal, and antiviral herb. You can even make it into a spray and apply to affected areas on your dog. You can also buy calendula as a salve and use it in different areas that are itchy for your dog. It will also help with pain relief and reduce any swelling.

Foot Soak

If your dog is going crazy chewing and itching their feet, you can do an Epsom salt foot soak to provide relief. Dissolve the salts in cool water and then let your dog soak its feet in it. Do not let your dog drink the Epsom salts, as it is also a laxative.

Zyrtec for Dogs: A Final Thought

Zyrtec is an effective medication for dogs that are suffering from allergies and are unable to find relief from natural remedies. However, Zyrtec can be dangerous to dogs that have existing liver and kidney problems and can cause harmful drug interactions with other medications. Vets generally recognize Zyrtec as a safe and effective way to treat allergy symptoms in dogs, but we still encourage pet owners to find a natural solution for long-term allergy relief.

If your dog seems to have allergies, talk to your veterinarian before starting traditional allergy medicine. You want to do this because many autoimmune disorders can mimic allergy symptoms. These conditions can cause skin conditions that may seem like a simple seasonal allergy. However, it could actually be an autoimmune disorder that requires specific medication. Autoimmune diseases can lay dormant and not show symptoms until adulthood. In fact, some immune disorders may not show up until the dog is under severe stress or has had a traumatic incident.

Lastly, it’s important to get a check-up if your pet starts to show symptoms of allergies, especially if it’s sudden and not a seasonal issue that you’re used to. Your vet will perform a physical examination, blood work, and urinalysis to make sure your pet is healthy. You’ll want to confirm that the reaction is just to an allergen, not an underlying medical condition. The full workup will also provide insight as to whether or not your pet is healthy enough to take Zyrtec or other allergy medications (if absolutely necessary). Your vet can monitor the progress of your dog while they are using the allergy medication. That way, they can make sure no adverse side effects arise.

About the author

Chelsea Hunt-Rivera

Chelsea Rivera is a Dedicated Pet Parent who loves to create amazing content for pet owners and is helping change pet wellness as the Head of Content for Honestpaws.com.