Hydroxyzine for Cats: Treat Feline Itching and Other Allergy Symptoms
Key takeaways:
Hydroxyzine is a prescription-only antihistamine most often used to treat itchy, allergic skin in cats.
Sedation is the most common side effect of hydroxyzine, with more serious side effects such as tremors or seizures occurring rarely.
Hydroxyzine is available as tablets, capsules, or a liquid suspension. You can give this medication to your cat with or without food.
Table of contents
Just like humans, cats can have allergies that lead to uncomfortable symptoms including itching. When your cat needs relief, your veterinarian might recommend a medication called hydroxyzine (Atarax, Vistaril).
Hydroxyzine is an antihistamine that may be used in cats for itching and other symptoms of allergies. Learn more about hydroxyzine and if it might be a consideration for your cat by reading further.
Hydroxyzine for cats at a glance
Common names | Hydroxyzine (Atarax, Vistaril) |
What it treats | Allergy symptoms including itching |
How it comes (forms) | Tablet, capsule, or liquid suspension |
Common side effects | Sedation, drinking more water, urine and stool retention |
Average cost | $5-$13 for a 30-day supply |
What is hydroxyzine for cats, and how does it work?
Hydroxyzine is a first-generation antihistamine. It works by blocking the receptors that histamine binds to that cause itching and inflammation. Hydroxyzine can have several other effects in the body, which include:
Causing sedation
Relieving cramps or spasms in the stomach, intestines, and bladder muscle
Providing mild pain relief (with the injectable form)
Widening tiny airways in the lungs
Reducing vomiting and some nausea
Search and compare options
When metabolized by the body, hydroxyzine is converted to cetirizine. You may recognize cetirizine as another antihistamine sold over the counter as Zyrtec. Cetirizine has similar effects to hydroxyzine but does not contribute to significant sedation. It is sold over the counter and does not have noticeable sedative effects. Because of this, cetirizine is more widely used.
What is hydroxyzine used for in cats?
Hydroxyzine is primarily used in cats for itching and allergic conditions involving histamine. Some cats may be more sensitive to the medication’s sedative and antinausea and vomiting effects. In these cats, hydroxyzine may be used to help with car travel or other situations where calming or sedation is desired.
In cats (and dogs), response to antihistamine medications is unpredictable and individualized. A cat may respond very well to hydroxyzine, or the medication may have very little benefit. But a cat who doesn't respond well to one antihistamine may respond much better to another. Here are some of the conditions for which hydroxyzine is used.
Atopic dermatitis
Atopic dermatitis (atopy) is a skin allergy condition commonly seen in cats. The immune system responds severely to many allergens, causing recurring skin issues. In cats, specific forms of allergic skin disease where hydroxyzine may be used include:
Hydroxyzine and other antihistamines have only modest benefits for atopic dermatitis on their own. For this reason, hydroxyzine is often used alongside another medication such as a steroid that suppresses the immune system's response to allergens.
Read more like this
Explore these related articles, suggested for readers like you.
Hydroxyzine may be more effective when taken regularly as a preventive medication. This can reduce the chance of a symptom flare-up, as opposed to treating in the middle of an active itchy skin flare-up. Using hydroxyzine this waymay help reduce the need for or the frequency of taking stronger medications such as corticosteroids.
Mast cell tumors
A mast cell tumor is a tumor that contains histamine granules. The release of these granules is what leads to histamine’s inflammatory effects on the body. Pets with mast cell tumors can experience recurrent effects of this process.
Antihistamines are not a treatment for the mast cell tumor itself. But they can help reduce the effects. They do this by blocking histamine’s ability to bind to receptors in a cat’s body.
How is hydroxyzine dosed and given for cats?
Hydroxyzine for cats comes in a tablet, capsule, or liquid suspension form. You can give all forms by mouth. You may also hide a tablet or capsule in food or a small treat to help with administration.
Vets use hydroxyzine off-label in cats. It is very common for medications to be prescribed in an off-label manner in veterinary medicine. There is no form of hydroxyzine only made for cats. Vets prescribe human brands — such as Atarax or Vistaril — or generic hydroxyzine tablets or capsules.
Unlike many other antihistamines, hydroxyzine is available by prescription only. A vet must determine dosing and frequency for the safest use.
Hydroxyzine is most often given every 12 hours. How long to give it depends on a veterinarian’s instructions and what you’re treating. Vets may suggest long-term use to help prevent itchy skin flare-ups. Or they may suggest use only for certain short-term situations.
Vets use the injectable form of hydroxyzine less often. But some may offer a hydroxyzine injection as a treatment at their veterinary clinic.
What are the common side effects of hydroxyzine in cats?
The most common side effect of hydroxyzine in cats is sedation. In some cases, this is a desired effect — when your cat is very itchy and restless, traveling by car, or in another stressful situation. The degree of sedation can vary a lot from cat to cat. Over time, the sedative effects may lessen.
Hydroxyzine may also cause side effects in cats. These include dry mouth, which humans taking hydroxyzine report. You may notice your cat drinking more water, and they may also retain urine and stool. For these reasons, hydroxyzine use should be considered carefully in cats with preexisting urinary bladder disease or constipation.
Tolerance to hydroxyzine is possible. A cat that responds well to it at first may show less benefit over longer periods of time. This tolerance may resolve if hydroxyzine is discontinued for an extended period, and it’s possible that benefits may be seen again if restarted.
What are the most serious risks of hydroxyzine for cats?
Antihistamines in general can have other side effects. These are not predictable and may vary in individual cats:
Behavioral changes
Excessive thirst
Depression
Hydroxyzine can contribute to birth defects and should not be used in pregnant cats. In humans, hydroxyzine is medically inappropriate during the first trimester of pregnancy.
The injectable form of hydroxyzine has been associated with local skin reactions (some severe) as well as tissue abscesses (swelling of infected/inflamed fluid under the skin).
Overdoses of hydroxyzine are most likely to lead to more pronounced sedation. However, there may also be an increased risk for:
Ataxia (difficulty with balance when walking)
Tachycardia (high heart rate)
Hyperthermia (elevated body temperature)
More serious effects of tremors and seizures, which occur rarely in some dogs, have not been reported in cats.
Concerned your cat may have gotten an overdose of hydroxyzine? Make sure to immediately contact your veterinarian or a pet poison hotline.
Does hydroxyzine interact with any other cat medications?
Hydroxyzine can interact with several other medications your cat may take. Using hydroxyzine together with these medications is not necessarily inappropriate. But discuss the risks and benefits with your vet if your cat takes any of the following medications:
Acetylcholinesterase inhibitors (neostigmine)
Anticholinergic agents (atropine, glycopyrrolate)
Benzodiazepines (diazepam, midazolam, alprazolam)
Cimetidine
Central nervous system (CNS) depressants (acepromazine, methocarbamol, phenobarbital, mirtazapine, trazodone)
Epinephrine
Opioids (tramadol, morphine, methadone, fentanyl)
Oral potassium salts
Prokinetic agents (cisapride, metoclopramide)
QT-prolonging agents (sotalol, ondansetron)
Tricyclic antidepressants (amitriptyline, clomipramine)
What should you do if your cat misses a dose of hydroxyzine?
If a dose is missed, it may be appropriate to wait until the next dose is due, which will usually be 12 hours later. In most cases, the effect of missing a dose will be minimal.
However, in cats that respond highly to hydroxyzine, missing a dose may have a more adverse effect on comfort or care. If this is the case for your cat, the following suggestions may be considered:
If only an hour or two has passed since the missed dose, it can still be OK to give hydroxyzine as soon as possible.
If your cat receives hydroxyzine every 12 hours, and more than 6 to 8 hours has passed since the missed dose, consider waiting until the next dose is due.
If you have specific questions about dosing or missed doses, contact your veterinarian.
The bottom line
Hydroxyzine is a prescription antihistamine that may be used alongside other medications for relief of chronic itching and skin irritation in cats. It doesn’t always help cats a whole lot when used on its own, but it may be more helpful to some cats than others. Hydroxyzine may also cause sedation. But other, more serious side effects are very uncommon in cats.
Because sensitivities to antihistamines in cats vary widely, hydroxyzine may be an option for a cat who has not responded well to a different antihistamine.
Why trust our experts?
References
American Animal Hospital. (2012). Antihistamines for dogs.
Banovic, F., et al. (2020). Effect of diphenhydramine and cetirizine on immediate and late-phase cutaneous allergic reactions in healthy dogs: A randomized, double-blinded crossover study. Veterinary Dermatology.
Brooks, W. (2024). Hydroxyzine (Atarax). Veterinary Partner.
Bruet, V., et al. (2022). Clinical guidelines for the use of antipruritic drugs in the control of the most frequent pruritic skin diseases in dogs. Veterinary Sciences.
Budde, J. A., et al. (2023). Hydroxyzine. Plumb's Veterinary Drug Handbook.
Cornell University College of Veterinary Medicine: Cornell Feline Health Center. (n.d.). Eosinophilic granuloma complex.
De Nardi, A. B., et al. (2022). Diagnosis, prognosis and treatment of canine cutaneous and subcutaneous mast cell tumors. Cells.
Moriello, K. A. (2018). Hair loss (alopecia) in cats. Merck Veterinary Manual.
Plumb’s Veterinary Medication Guides. (2020). Hydroxyzine [package insert].
Weir, M., et al. (n.d.). Miliary dermatitis in cats. VCA Animal Hospitals.
