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)

Share

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.


Catster's Digital Magazine is Back!

Vet-approved health & behavior advice

Real cat stories & community features

Chatting About the Rainbow Bridge, Euthanasia, and Laughter During Grief | Chatty Cattys, Episode 24

If you’ve ever felt the loss of a beloved cat, or are dreading the day when your pet crosses the rainbow bridge, you’ll...

The Simple Reasons Cats Refuse to Let Anyone Use the Bathroom Alone

Cats have an extraordinary talent for making themselves present in the most inconvenient places, and the bathroom ranks near the top of the...

A Paw-sitive Milestone: Canada Officially Becomes a Declaw-Free Nation

Canada has officially become a declaw-free nation. On May 25, 2026, a new regulation was filed in Ontario under the Provincial Animal Welfare...

The Surprisingly Simple Ways to Help a Cat With Hairballs

Cats spend an astonishing amount of time grooming. It is part hygiene routine, part comfort ritual, and part instinct that traces back generations....

More related

Will Coyotes Eat Cat Food? Vet-Approved Explanation & Safety Tips

Coyotes can be a real danger, especially if you have outdoor pets. The farther into their territory that humans encroach, the more interactions...

Does My Cat Need a Veterinary Neurologist? 5 Vet Reviewed Signs

Nothing is more terrifying than having your cat diagnosed with a health condition. It’s tough to see them suffering, whether it’s a minor...

We Chat With Caitlin Major About Her Kitty Comic Strip “Manfried the Man”

Let’s be honest, at some point we’ve all looked over at our charismatic feline companions and thought they were definitely worthy of being...

Will a Cat Purr When They’re in Pain? Vet-Verified Facts & Advice

As cat parents, most of us see a cat’s purr as a sign that our feline is happy and content with their life....

Keep reading

10 Best Cat Hair Remover Tools in 2026 – Reviews & Top Picks

As much as we love our cats, the same cannot be said about the tiny sticky hairs always present on clothes, furniture, and bedding. But it is the price we must pay for the comfort, joy, and companionship these little...

woman leaning jeans with cat hair remover

10 Ways to Monitor Your Cat’s Health at Home: Vet Verified

Thanks to their instincts for self-preservation, cats are masters at hiding signs of illness or injuries. If you want to catch medical problems early, you must learn to spot the signs of trouble despite your cat’s attempts to hide them....

cat resting withowner on sofa at home

Do Cats Need a Cat Tree? Vet Approved Pros, Cons & Considerations

Cats love to be up high and observe everything around them but also enjoy having their own space while they sleep their day away. Cat trees are a common staple in most cat-owning households. Not only do they provide that...

cat on top of a cat tree

Feline Idiopathic Cystitis in Cats: Signs, Causes, and Care

Urinary tract diseases are fairly common in cats, so it’s important for cat owners to be well-informed about this area of cat health. Cats can contract several different kinds of urinary tract diseases. Veterinarians will conduct tests to diagnose the...

cat pee on carpet

Do All Cats Have a Primordial Pouch? Vet-Reviewed Facts & FAQ

Cats can be a real mystery for a lot of reasons. They’re unique and independent creatures that often leave us scratching our heads. One of the unusual things you may have noticed about cats is that it seems like they...

Fat Cat On Floor

Why Does My Cat Throw Up After Eating? 8 Vet-Reviewed Reasons & Solutions

If your cat starts throwing up after they eat, it’s obviously very alarming behavior that you want to get to the bottom of as soon as possible. But what exactly could be the cause of your kitty’s stomach issues? Vomiting...

sick cat vomiting the food on a white background

Are Carnations Toxic To Cats? Vet-Reviewed Health & Toxicity Explanation

Is there anything as lovely as having a fresh-cut flower display in your home? The bright colors and beautiful blooms of flowers like carnations can increase the positive vibes in your home and ease stress. Is it safe to have...

Catster_Are Carnations Toxic to Cats

5 Side Effects of Microchipping Your Cat – What You Should Know! Vet-Approved Info

These days, microchipping pets is commonplace and beneficial for you and your pet for many reasons. One of the risks of owning pets is that they can get lost, stolen, or otherwise escape from you. Before microchipping, you had to...

Microchip implant for cat

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.