Get

In Your Inbox

Catster is reader-supported. When you buy via links on our site, we may earn an affiliate commission at no cost to you. Learn more.

Zyrtec for Cats: Dosage, Uses & Side Effects (Vet Answer)

white pills tablets

Allergies in cats can sometimes have the same symptoms as us – watery eyes and nose, mild congestion, and sometimes coughing. More frequently, allergies in cats will manifest as itchy skin, redness, and/or swelling of the skin.

The brand name Zyrtec may sound familiar to you. It’s a common over-the-counter (OTC) allergy medication that many of us have taken in the midst of pollen season. But can cats take Zyrtec? Yes, Zyrtec can be given to cats, but it’s important to consult your veterinarian before giving Zyrtec to your cat. In this article we’ll discuss what Zyrtec is, if and how you can give it to your cat, and potential side effects that your cat may experience.

divider cats oct 2024

What Is Zyrtec?

Zyrtec is the brand name for the drug Cetirizine HCL (Cetirizine Hydrochloride). Zyrtec is an antihistamine allergy medication. When your cat’s body reacts to an irritant and/or an allergen, the body will release histamine. This is a natural substance that occurs and can be released with no problems. With allergies and/or an allergic reaction, excessive histamine can cause itching, redness, and sometimes swelling. Antihistamines work by blocking histamine from attaching to certain cell receptors that then cause the effects listed above. Zyrtec is in the class of antihistamines that are classified as an H-1 blocker.

woman-giving-pill-to-cat
Image Credit: New Africa, Shutterstock

How Is Zyrtec Given to Cats?

Zyrtec is given orally. If your veterinarian recommends you give the OTC product, it comes as a tablet, chewable tablet, gelcap, or a children’s formula liquid. The gelcap will likely not be recommended due to the dosing your cat needs. If your cat is difficult to give medication to, your veterinarian may also have the medication compounded. This means that a compounding pharmacy will make the medication into different forms than what is available OTC and can also make it flavored.

Zyrtec can be given to cats every 12–24 hours, or once to twice a day. It does not have to be given with food, though giving a cat medication can be extremely difficult. Sometimes giving it in food can be much easier as your cat may eat it more easily in a snack such as tuna. Giving Zyrtec with or without food will not alter its effectiveness.

divider 3 paws

Zyrtec Dosage for Cats

So how much Zyrtec should you give your cat? First, It’s important that you know their current weight. Depending on the weight of your cat, the dosing for Cetirizine is 1 mg of Zyrtec per 1 kilogram of your cat’s body weight. Typically, this will be 2.5 mg to 5 mg total. However, make sure to check this with your veterinarian as they may recommend a different dose.

What Happens If You Miss a Dose?

The best part is that there are no serious side effects if a dose is not given, or if your cat just won’t allow you to give them the medication. Zyrtec is not a medication that has to be weaned up or down in order to be effective for your cat.

It’s worth noting that significant allergies in cats are often not affected by OTC antihistamine products. In other words, you will not notice any improvement in the allergy symptoms if your cat has significant allergies. If you are regularly giving your cat the recommended dose of Zyrtec, and both you and your veterinarian are not noticing an improvement in their allergy signs, it may not work for them. At that time, you should discuss other options with your veterinarian.

If you need to speak with a vet but can't get to one, head over to PangoVet. It's an online service where you can talk to a vet online and get the advice you need for your pet — all at an affordable price!

Preventative wellness PGV mention keep cat healthy Preventative wellness PGV mention keep cat healthy mobile

Potential Zyrtec Side Effects in Cats

In general, cats can be very stubborn and dramatic when getting any medication. Zyrtec does not have any common side effects, but some cats will spit, drool, foam at the mouth, and be dramatic simply because they are being medicated.

Mild drowsiness is possible, especially with smaller cats, but does not always occur.

If your cat has underlying liver and/or kidney disease, your veterinarian may recommend a lower dose and/or a less frequent dose. This is because it may take your cat longer to process the medication if they have the existing conditions.

woman brought her maine coon cat to the vet
Image Credit: Gorodenkoff, Shutterstock

divider cat paws 2 oct 2024

Frequently Asked Questions (FAQ)

Can I Give My Cat Zyrtec D?

No! This can be extremely harmful and potentially deadly for your cat. The “D” in the name stands for decongestion, and this formula contains the drug pseudoephedrine. Pseudoephedrine can be extremely harmful to dogs and cats, and can be highly fatal. Never give your cat or dog any medication containing pseudoephedrine unless explicitly prescribed by your veterinarian.

Is Zyrtec Effective?

Zyrtec can be effective for mild pruritus (itchiness) in your cat. However, for severe underlying allergies, OTC medications are often not enough. Your cat may need a new diet, appropriate flea preventative, prescription allergy medications, or steroids to completely stop itching.

divider cat faces oct 2024

Conclusion

Allergies in cats are most frequently seen as itching skin. Over-the-counter antihistamines can sometimes be helpful in relieving some of the most common symptoms of allergies. Zyrtec is one of these common OTC medications that can be given. It comes in oral form and should be dosed based on your cat’s current weight and your veterinarian’s recommendations based on that weight.

Zyrtec is given as an oral medication either in tablet or liquid form, or your veterinarian may have a compounding pharmacy make the medication into a different form. There are very few side effects aside from occasional drowsiness. It’s important that you never give your cat Zyrtec-D, and you are aware that any OTC antihistamine may not be effective. Always work with your veterinarian for their best recommendations.


Featured Image Credit: Purricious, Shutterstock

Want content like this delivered to you?

Sign Up For Our Newsletter

News, insights, expert advice, and everything cat

* By submitting, you agree to our Terms & Conditions and Privacy & Cookies Policy.




How useful was this post?

Click on a star to rate (you can leave written feedback after clicking submit)

Help us improve Catster for pet parents!

Your feedback really matters.

What did you like about this post? Also how can we improve it?

Join the conversation

Leave a Reply

You’re very welcome to leave a comment or question. Please know that all comments must meet our community guidelines, and your email address will NOT be published. Let’s have a positive and constructive conversation.


Talk With A Vet Online

Peace of mind,
anywhere, anytime

Affordable vet advice

When Were Cats First Brought to America? Historical Facts & FAQ

Cats are believed to have entered the U.S. by ship in the early 1600s. At the time, they were known as ship cats...

What Is the Rainbow Bridge That Cats Cross? Legend Explained

After the sad passing of beloved pet cats, many owners will often say that their cats have crossed the Rainbow Bridge. The Rainbow...

4 DIY Cat Beds Using Baskets You Can Make at Home (Vet-Approved With Pictures)

If you’re like most cat owners, you’ve probably seen dozens of different DIY cat beds over the years. But have you ever considered...

10 Pet-Friendly Hotels In San Francisco (2026 Update)

If you’re visiting the big city of San Francisco, there are tons of options for folks who want to travel with their cat....

More related

How Rare Are Brown Cats? Vet-Verified Cat Genetics

When was the last time you spotted a brown cat? If you answered, “I can’t remember,” or, “Never!” you form part of the...

Can Cats Get Razor Burn? Vet-Reviewed Care Facts

If you have a cat, there is a good chance that they will need to be shaved at some point in their lives,...

Insect-Based Cat Food: Vet-Reviewed Pros, Cons & FAQs

You may have heard about the recent trend of pet food made with insects rather than more conventional animal protein. While this might...

Why Is My Cat Drinking a Lot of Water Suddenly? 6 Vet-Reviewed Reasons

Cats, due to their nature and small size, don’t drink large amounts of water. The typical, healthy house cat will drink about 5...

Keep reading

How to Tell If a Cat Is Allergic to Food: Vet-Approved Diagnosis Methods & Treatments

If you’re a cat owner, you probably know how important it is to provide them with a balanced and healthy diet. However, what happens when your feline companion starts experiencing unexplained signs like vomiting, diarrhea, or itchy skin? These could...

Cat scratching his ear while laying on a bed

Is Aglaonema Toxic to Cats? Vet-Verified Houseplant Advice

House plants are a fantastic way to give your home some life, so much so that many people have taken up the role of plant parents, adorning their space with greenery. Aglaonema commutatum, also known as the Chinese evergreen plant,...

Catster_Is Aglaonema Toxic to Cats

Can Cats Have Allergies? Vet-Approved Signs, Treatment & Prevention Tips

Yes, cats can most definitely get allergies. Just like humans, cats can develop seasonal, environmental, and food allergies, and they can develop allergies to flea saliva too. Some allergies in cats are mild, but they can get severe, usually due...

cat scratching behind head

How Much Is Too Much To Spend On A Sick Pet? Vet-Reviewed Facts & FAQ

Taking your pet to the vet for even routine care, such as vaccinations, can be pricey. But what about when your pet is ill and needs long-term or emergency care? Those costs could become astronomical, which begs the question of...

cat in the clinic with veterinarian and owner

What Are Cats Scared Of? 8 Vet-Reviewed Feline Fears & How to Help 

Cats are highly attuned to their environment and are sticklers for routine. This sensitivity can make them easily startled by certain objects, sounds, and situations, and it all comes down to a cat’s natural instinct for self-preservation and unease surrounding...

scared cat hiding behind the drawer

My Cat Is Bored but Won’t Play, What’s Wrong? 6 Common Reasons

Most cats play throughout their life, though they are most playful in their kitten years.Under human care, cats don’t need to hunt or do many other things to aid in their survival. Therefore, they often have a lot of pent-up...

sad, bored or sick cat

Kitten Development: First 12 Weeks (Vet-Reviewed Guide)

Bringing a new kitten home is a joyous and exciting occasion for all soon-to-be cat parents. This usually occurs when a kitten is between 8 and 10 weeks of age, depending on their size, health, vaccination protocol, and breed. However,...

american shorthair kitten

Why Is My Kitten Sneezing? 5 Vet Approved Reasons

Kittens are some of the most adorable creatures on earth. They often weigh just a few ounces at birth and quickly grow into sweet bundles of feline perfection. But kittens, just like human babies, sometimes sneeze, refuse to eat, and...

a kitten sneezing in pink background

Love Cats? So Do We! Join the Catster Community

Stay informed with expert pet care insights delivered straight to your inbox! Discover professional guidance on animal behavior, feeding tips, trusted product picks, and much more.




Sign up for the Catster Email Newsletter

Stay informed with expert pet care insights delivered straight to your inbox! Discover professional guidance on animal behavior, feeding tips, trusted product picks, and much more.