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!

PangoVet_Mention-in-Content for PangoVet2 save money

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

3 Food Sources of Thiamine for Cats (Vitamin B1): Vet Reviewed Options

We all want our cats to be healthy, happy, and with us for as long as possible. That’s why we take them to...

Why Is My Cat Is Sitting Like a Person? Is That Normal?

Most cat owners can agree that there’s never a dull moment in a feline household. No matter your cat’s personality, they’re always up...

10 Best Cat Litter Scoops of 2025 – Reviews & Top Picks

You may not give much thought to your litter scoop, but having the right one is just as important as having the right...

Fear-Free Vet: Vet-Verified Advantages, Disadvantages & FAQ

Vet visits have always been instrumental in promoting our pets’ health and longevity. But for most cats, the experience can be more stressful...

More related

Boating With Cats: A Complete Guide

Cats are notoriously scared of water. But many breeds have been sailing on boats for centuries. Originally, cats were essential for boating due...

Can Humans Eat Cat Food? Vet-Reviewed Facts & Info to Consider

Have you ever been putting together your cat’s meal for the night and thought to yourself, “Wow, I want to taste this delicious...

What Should I Do for Adopt a Cat Month? 5 Great Ways to Help

We have International Cat Rescue Day, which falls on March 2nd, and National Adopt a Cat Month each June. These events are in...

Adopting a Senior Cat? 10 Vet-Approved Things to Consider

Adopting a cat is a huge decision in a person’s life. When you visit a local animal shelter or rescue, you’ll find dozens...

Keep reading

Can Cats Eat Sausage? Vet-Reviewed Nutritional Facts & FAQ

As cat lovers, we all want to spoil and treat our feline friends, but we also want to keep them happy and healthy. While your cat may show interest in some of your human food, not everything on your plate...

Can Cats Eat Sausage

My Cat Won’t Eat: Causes, Feeding Recomendations & When To Worry (Vet-Verified)

Cats are pretty good at hiding it when they aren’t feeling well, and a sudden lack of interest in eating is a cause for concern. Cats can go off their food for many reasons, from stress to dental pain and...

Tabby cat eating food from white bowl

Are Air Plants Toxic to Cats? Vet-Reviewed Houseplants

We love our cats, and we want what’s best for them. So, when it comes to choosing houseplants, we want to make sure that they’re safe for our feline friends. But are air plants toxic to cats? The short answer...

Catster_Are Air Plants Toxic to Cats

How Long Do Cats Mourn the Loss of Another Cat? Feline Grieving Explained (Vet-Verified Info)

Humans are not the only beings that experience emotions. Not only can our cats experience a broad spectrum of emotions that humans share, but they also live entirely complicated lives that we don’t understand. When it comes to a cat...

sad calico cat with third eyelid

Can a Cat Take Baby Aspirin? Vet-Approved Facts & Safety Tips

No one wants to think about their beloved pet in pain, so it can be tempting to give your cat some relief from your medicine cabinet. If you suspect your cat is hurting, you might wonder if a cat can...

Baby Aspirin Compress Tablets Medicine

Are Tapeworms in Cats Contagious? Vet-Reviewed Health Facts

Testing for parasites and deworming are important aspects of pet care, especially in puppies and kittens. There is a relatively high likelihood that any dog or cat will become infested with some type of internal or external parasites, be they...

tapeworm in a cat's stomach

How Does a Cat Purr? The Evolution & Meaning Behind a Purr (Vet Reviewed)

Cats are known for their adorable vocalizations, and their purring is usually a sign of contentment and happiness. But have you ever wondered how your cat makes that calming vibration? Cats purr by vibrating their laryngeal muscles through several mechanisms....

cat purring

Why Does My Cat Keep Meowing? 7 Reasons Why They Won’t Stop

Meowing is one of your cat’s main sources of communication with you. Most meows are harmless and hearing them is a normal part of your day. But if your cat is meowing excessively, you may wonder why. Read on to...

cat meowing or chirping by the window