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Hydroxyzine (Atarax) for Dogs

By | Last Updated: 22nd February 2023

What is Hydroxyzine used for in dogs

Hydroxyzine, an antihistamine, is a medication used to treat allergic reactions that occur from insect and snake bites, vaccines, ear infections [9] and various other inflamed and itchy skin conditions, including dermatitis. It is known to even reduce nausea and anxiety stemming from an allergy [6, 7].

How does hydroxyzine work

Histamine is a chemical released by the body when it encounters allergies and inflammation. Antihistamines like hydroxyzine, bind with histamine receptor cells, thus negating their ability to accept the onslaught of histamine, which in turn prevents or reduces allergic reactions like skin inflammation and itching [6].

Antihistamines, in general, are preferred over cortisone for long-term use for treating atopical skin conditionsHydroxyzine is considered safe as it does not affect your pet’s heart rate or alter their stomach acid secretions.

Quick Information

Hydroxyzine for Dogs

Generic name: Hydroxyzine HCl, Hydroxyzine pamoate [4, 1]

Brand name: Anxanil, Atarax, Vistaril  [5]

Type: Antihistamine [5]

Who can take it: Dogs, cats [5]

FDA Approved: Not for Veterinary use [3]

Availability: Prescription only [5]

Available forms: Oral liquid, capsule, tablet, injection [5]

Hydroxyzine dosage for dogs: How much to give

Hydroxyzine should never be given to a dog without a veterinarian’s prescription. The dose is based on the size of the dog, with the usually accepted dosage being 1 mg per pound of body weight, equivalent to 2 mg per kilogram, 2-3 times per day [3, 4, 7].

How long the medication is to be administered depends on the condition being treated and the severity thereof. Never stop the treatment as soon as you see any sign of improvement; instead, finish the whole course that has been prescribed [7].

How long does hydroxyzine take to work

It usually starts to work within 20 to 45 minutes [8].

Hydroxyzine (Atarax) side effects in dogs

Medications taken to curb allergies can sometimes themselves cause such reactions. You will need to talk to the vet immediately if you see any typical signs of allergy, including:

  • Troubled breathing
  • Swelling of the tongue, lips, face
  • Hives
  • Seizures [11]

The administration of hydroxyzine may elicit some common side-effects, more likely in case of long-term use [5, 6, 3]:

  • Lethargy
  • Sedation
  • Diarrhea
  • Lack of appetite
  • Vomiting
  • Increased urination
  • Difficulty in urinating
  • Altered behavior
  • Dizziness
  • Lack of coordination

Contraindications: When should you not give hydroxyzine

Always inform the vet about any existing medical condition your dog might be having, and any medication it is being given [6]. Hydroxyzine is inadvisable in case of:

  • Hypertension
  • Prostate enlargement
  • Heart and lung diseases
  • Bladder-neck obstruction [3]
  • Pregnant and nursing dogs [5]
  • Dogs being given barbiturates, tranquilizers, and epinephrine [6]

Make sure to inform your vet if your dog has had an allergic reaction from this drug in the past, as it is likely to have it again, even if it is prescribed for a different condition.

Some alternatives are diphenhydramine (Benadryl) and trimeprazine (Temaril ), neither of which should be given in conjunction with hydroxyzine.

Signs of overdose

If your dog seems overly drowsy, it is probably resulting from an overdose. Taking your dog to a vet might also reveal low blood pressure levels. If you suspect an overdose, immediately talk to the vet or call the ASPCA Animal Poison Control Center Helpline (1-888-426-4435).


    1. Hydroxyzine – DrsFosterSmith.com
    2. Hydroxyzine Pamoate Side Effects in Dogs – VetInfo.com
    3. Hydroxyzine for Dogs – DogHealthCoach.com
    4. Hydroxyzine HCl – 1800PetMeds.com
    5. Hydroxyzine – PetMD.com
    6. Hydroxyzine (Atarax®, Anxanil®, Vistaril®) for Dogs and Cats – PetPlace.com
    7. About hydroxyzine capsules for allergies in pets – PetCareRX.com
    8. Hydroxyzine – PetCareRX.com
    9. Allergies in Pets – RauAnimalHospital.com
    10. Antihistamines for Dogs – Natural-Dog-Health-Remedies.com
    11. The Side Effects of Hydroxyzine on Dogs – Cuteness.com

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