Can I give my cat hydroxyzine?

In this article:

• Hydroxyzine for cats
• Safety
• Dosage
• Alternatives

In this article

• Hydroxyzine for cats
• Safety
• Dosage
• Alternatives

Hydroxyzine is a prescription antihistamine used to treat contact dermatitis and other allergic reactions in cats. It is safe for cats but is less effective in cats than people. It works best when administered before the cat is exposed to a reaction-inducing event like a vaccine shot. Vets are more likely to use it long-term to prevent itchy skin due to contact allergies. However, cats develop tolerance to the drug over time, making it less effective. When an antihistamine is called for, a veterinarian may choose to use cetirizine, a common over-the-counter antihistamine. Cetirizine is an active form of hydroxyzine but is less likely to have sedative side effects.

RELATED: Save up to 80% on hydroxyzine

What is hydroxyzine used for in cats?

Hydroxyzine is not a common cat drug and has not been approved by the FDA for use in animals. In cats, there are recommended hydroxyzine dosages as an antihistamine or as a treatment for itchy skin (pruritus) due to allergic reactions.

Though doses aren’t standardized, veterinarians could use hydroxyzine as a sedative before vet visits or veterinary procedures. Hydroxyzine is FDA-approved for use as a sedative in people. 

Hydroxyzine is also used as an anti-anxiety medication in people because of its sedative effects. Veterinarians may choose to use it this way, but it’s not tested or recommended as an anti-anxiety medication in animals.

Sensitivity reactions 

Tissues produce histamines in response to emergencies like injuries or parasites. They are powerful instigators of inflammation and start the process that produces swelling, redness, itching, pain, lowered blood pressure, and other symptoms associated with infections, injuries, and allergic reactions. Antihistamines like hydroxyzine block the actions of histamines to relieve inflammation and its related ills. 

Cats also generate histamines in response to allergens, infections, or injuries, but they play less of a role in inflammation in a cat’s body than in a person. Antihistamines are less effective at treating symptoms like itchy skin. There is some doubt that they are effective in quelling acute inflammation in a cat. 

Still, antihistamines like hydroxyzine can help relieve some symptoms, but in a more limited way than in people. Hydroxyzine and other antihistamines may work best when given before the cat is exposed to something that would provoke a reaction, such as a vaccination. It is more common for veterinarians to prescribe hydroxyzine as a long-term prevention. 

Itchy skin

Veterinarians most commonly use hydroxyzine in cats with itchy skin due to contact allergies (atopic dermatitis). 

Allergic reactions, hives, food allergies, flea bites, and insect bites can cause itchy skin in cats. The most common feline skin condition treated by veterinarians is feline atopic skin syndrome (FASS), a chronic, itchy condition caused by sensitivity reactions to environmental allergens.

Again, antihistamines like hydroxyzine are not as effective at treating itchy skin in cats as they are treating people or dogs with itchy skin. Instead, veterinarians turn first to corticosteroids like prednisolone or dexamethasone. However, because steroids involve unpleasant side effects, a veterinarian may use hydroxyzine as a preventive treatment for itchy skin to reduce the burden of corticosteroid treatment. 

Is hydroxyzine safe for cats?

When given under the direction of a veterinarian, hydroxyzine is safe for cats as a symptom-relief medication. 

Hydroxyzine should never be given to cats that have had an allergic reaction to hydroxyzine or cetirizine.

Veterinarians are advised not to give hydroxyzine to cats with:

• Bladder obstruction
• Heart failure
• Severe heart disease
• Stomach obstruction

Veterinarians will use hydroxyzine cautiously in cats that have:

• Urination problems
• Enlarged prostate
• Kidney disease
• Liver disease
• Heart disease
• Thyroid problems
• Glaucoma

Hydroxyzine is also used with caution in older, pregnant, or breastfeeding cats. 

Hydroxyzine can cause birth defects when used in a pregnant cat. Veterinarians do not know if hydroxyzine is present in a cat’s breast milk. If it is, it could cause problems in nursing kittens.

Side effects of hydroxyzine in cats

In cats, the most common side effects of hydroxyzine are:

• Sleepiness
• Depression
• Increased thirst
• Over-excitement 
• Behavioral changes

Hydroxyzine may also cause dry mouth, though this side effect is more common in dogs. Make sure the cat has uninterrupted access to a filled water bowl.

Contact a veterinarian if any of these side effects worsen.

The most serious side effects a cat may experience are allergic reactions to the drug. Immediately contact a veterinarian or veterinary hospital if a cat shows signs of a hypersensitivity reaction. 

Interactions of hydroxyzine with other pet meds

To avoid possible drug interactions, tell the veterinarian about all the drugs, supplements, and herbal remedies the cat is being given, particularly:

• Other antihistamines
• Drugs that make the cat sleepy, such as narcotic pain relievers, barbiturates, tranquilizers, or similar CNS depressants
• Drugs that treat asthma (inhalers), vomiting, digestive system problems, or overactive bladder called anticholinergic drugs
• Epinephrine

Pet owners who give their cat CBD should talk to the veterinarian before starting the cat on hydroxyzine. CBD may worsen many of the sedative side effects of hydroxyzine, such as sleepiness, fatigue, and depression.

All antihistamines can significantly distort the results of allergy tests. Cats that are scheduled for a skin allergy test should not take antihistamines three to seven days before the test.

Hydroxyzine dosage for cats

The standard hydroxyzine dosage for cats is 5–10 mg, given every 12 hours either as an antihistamine or a treatment for itching.

The veterinarian can prescribe either human versions or veterinary formulations of hydroxyzine. Hydroxyzine HCl comes in tablets or as an oral solution for easier dosing. Human versions also include an oral syrup, but some oral syrups contain alcohol. Vistaril (hydroxyzine pamoate) only comes as capsules. Dosage strengths are too large for cats. 

The smallest available dosage strength for hydroxyzine HCl tablets is 10 mg. This is the upper end of the recommended dose. The 10 mg tablets are not usually scored to allow them to be easily broken into smaller doses, so pet parents may need to use an oral solution to give doses smaller than 10 mg.

Can cats overdose on hydroxyzine?

Cats can overdose on hydroxyzine. Call the ASPCA Poison Control Center or an emergency veterinary clinic if a cat has been given too much hydroxyzine.

Symptoms of a hydroxyzine overdose in dogs are well-documented, but there’s little information about how an overdose affects a cat. The most likely signs of a hydroxyzine overdose are sedation and sometimes over-excitement. In dogs, high doses of hydroxyzine can cause tremors, shivering, and sometimes seizures.

Never give a cat more than the prescribed dose or give it more frequently than instructed. In the veterinary medicine literature, the maximum recommended dosage for cats is 10 mg given every 12 hours.

Can I give my cat hydroxyzine every day?

Hydroxyzine is intended as a symptom-relief medication but is usually used as a long-term preventive therapy. There is no limit on how long a cat can take hydroxyzine. However, cats develop a tolerance for an antihistamine over time. Eventually, continued doses of hydroxyzine will stop working. The veterinarian will probably switch the cat to an antihistamine of a different class. 

How to give your cat hydroxyzine

Only give a cat hydroxyzine under the direction of a veterinary professional. When dosing the cat, pet parents have the option of using tablets, oral solution, or oral syrup.

• Follow all the veterinarian’s instructions. 
• Cats can take a hydroxyzine dose with or without food. If the cat gets sick after a dose given on an empty stomach, try giving future doses with food.
• If you’re not experienced at administering tablets to your cat, ask a veterinary professional to demonstrate the proper technique.
• If you give the cat an oral syrup or oral solution, use the measuring device that comes with the medicine to measure out doses. The veterinarian can supply an appropriate calibrated measuring device.
• If a dose of hydroxyzine is missed, give it as soon as it’s remembered. If it’s almost time for the next dose, skip the missed dose and give the next dose as scheduled.
• Store hydroxyzine tablets, oral solution, and oral syrup in a tightly closed, light-resistant container at room temperature. Do not freeze the liquid versions.
• Hydroxyzine doses can be stopped at any time without tapering doses.

Hydroxyzine alternatives for cats

Hydroxyzine isn’t necessarily a veterinarian’s first choice for itchy skin or sensitivity reactions. The preferred treatments are:

• Corticosteroids such as prednisolone
• Immune suppressants such as cyclosporine or oclacitinib
• Allergen-specific immunotherapy
• Essential fatty acids
• Maropitant
• Gabapentin

Veterinarians are more likely to use hydroxyzine or another antihistamine as a preventive treatment for atopy, either before exposure or as a long-term preventive treatment. This helps reduce the cat’s exposure to corticosteroid side effects and complications. 

If an antihistamine is appropriate, veterinarians can choose from a variety of antihistamines. Many don’t cause drowsiness to the degree that first-generation antihistamines like hydroxyzine do. One alternative is cetirizine, an active version of hydroxyzine. Better known as brand-name Zyrtec, cetirizine doesn’t cross the blood-brain barrier and is less likely to cause drowsiness and depression in a cat. Other antihistamines used in cats include:

• Chlorpheniramine
• Cyproheptadine
• Clemastine
• Loratadine 
• Fexofenadine
• Diphenhydramine

The antidepressant amitriptyline is also a powerful antihistamine and can be used to treat pruritus in cats. 

One problem with antihistamines is that animals gradually develop tolerance for the drug. They eventually lose their effectiveness. In that case, the veterinarian may need to stop treatment and restart with a different class of antihistamine.

Summary

Antihistamines like hydroxyzine are not commonly used in cats. However, veterinarians can use hydroxyzine for a cat’s itchy skin or allergic reactions. They typically put cats on hydroxyzine or similar pet medications for long periods as a preventive medicine rather than a symptom reliever.