Quick Take
- Hydroxyzine can calm your dog's allergies, though in some dogs it triggers the opposite reaction you'd expect. See the side effects →
- Not every itchy dog can safely take hydroxyzine. Certain conditions make it a dangerous choice that many owners overlook. Check the contraindications →
- An overdose can look deceptively mild at first, but the window to act is much shorter than most people realize. Understand the treatment window →
- The right dose isn't one-size-fits-all, and getting it wrong tips the scale from relief to seizure territory fast. View the dosage chart →
When your dog is scratching incessantly due to itchy skin or allergies, you want to help. Although you can treat your own allergies with over-the-counter medication, those medications often contain other ingredients that are not safe for dogs. But your vet can prescribe single-ingredient medication, including hydroxyzine, to help your itchy pup find some relief. Learn more about hydroxyzine, including when dogs may need it, the right dosage, and alternatives you might consider. Always consult with a vet before giving your pet any medication.
What is Hydroxyzine?
Hydroxyzine falls under the category of antihistamines and is used to treat allergies in dogs. However, there are other treatments for allergies in dogs that may be more effective than hydroxyzine. Ultimately, your veterinarian will decide which treatment option is best for your pet. If hydroxyzine is prescribed, mild side effects may include drowsiness. However, in cases of an allergic reaction to the medication or overdose, your pup may experience seizures.
When Do Dogs Need Hydroxyzine?
Technically, hydroxyzine is not a pup-specific medication. It was initially created for humans, but vets have been prescribing it for dogs due to its efficacy in treating allergic reactions, allergic skin diseases (like atopic dermatitis), severe itching (pruritus), hives, and motion sickness, as well as mild calming effects that help manage anxiety.
Motion sickness is more common in puppies than in older dogs, though it can affect dogs of all ages. Hydroxyzine helps relieve motion sickness in dogs, making car rides more comfortable and even enjoyable.
Hydroxyzine may also treat allergic reactions in dogs, which can manifest in various ways, including itchiness, redness, and swelling.
Just like you, your pup sometimes needs a tissue too.
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Dogs that suffer from seasonal allergies experience a range of symptoms, including itchy eyes and skin. Hydroxyzine may be used in some cases, though your veterinarian will make that determination based on your pup’s specific needs. They may also suggest alternatives.
When atopic dermatitis is present, affected dogs experience excessive itchiness. According to the Cornell University College of Veterinary Medicine, this skin disease affects 10–15% of all dogs.
Hydroxyzine Side Effects and Risks in Dogs
As with any medication, there are some associated side effects or risks. In most cases, your dog may simply become drowsy after administration. However, your dog may respond in the opposite way, displaying unusual excitement or hyperactivity. Other side effects include tremors, seizures, and constipation. Additionally, your pup may experience a dry mouth and more thirst than usual, so ensuring they have access to plenty of fresh water is essential.
Signs of Hydroxyzine Overdose/Allergies in Dogs
More severe side effects, such as tremors or seizures, require immediate veterinary attention. In cases of overdose, you may notice excessive excitability or drowsiness. Your pup may stumble or pass out, and their body temperature may be higher than normal. In these cases, contact poison control immediately.
The ASPCA Animal Poison Control Center’s phone number is (888) 426-4435; it is open 24 hours a day, 365 days per year.
When Is Hydroxyzine Not an Option for Your Dog?
There are certain situations in which hydroxyzine is not suggested for dogs. For example, if your pup has a urinary or gastrointestinal obstruction, this medication should not be used. The same applies to dogs with heart failure or those who are allergic to cetirizine. Vets are especially cautious with pregnant dogs or those with seizure disorders. Each case should be reviewed thoroughly, with a complete medical history, to reduce the risk of overdose or an allergic reaction.
If hydroxyzine isn’t appropriate for your dog, there are alternatives to explore.
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Hydroxyzine for Dogs Dosage Chart
| Weight in pounds | Dosage of Hydroxyzine |
|---|---|
| 5.5-11.00 | 3-4 ml (Liquid) |
| 11.01-22 | 10 mg |
| 22.01-33 | 25 mg |
| 33.01 + | 50 mg |
How to Treat Hydroxyzine Overdose in Dogs
If you suspect hydroxyzine overdose in your pup, the poison control line will offer specific instructions to help. The ASPCA confirms that in cases of antihistamine toxicosis, the response in dogs varies significantly depending on the dose administered. They also note that the most commonly reported effects include sedation at lower doses, while higher doses tend to cause hyperactivity and eventual seizures. These symptoms can appear as soon as 10 minutes or as long as 11 hours after ingestion. Symptoms may persist for 7 to 10 days.
Hydroxyzine can help relieve allergies, but you must be careful when dosing.
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If a pup is symptomatic, treatment requires veterinary care to assess any life-threatening symptoms. The anticonvulsant vets typically administer following a hydroxyzine overdose is diazepam. It may be administered intravenously or intramuscularly to help control the excitability the medication can produce in dogs. Additionally, your vet may administer barbiturates, isoflurane, dopamine, or norepinephrine.
