Hydroxyzine Dosage For Dogs Calculator, Chart & Safe Guide

If your dog is itchy, sneezing, has watery eyes, or is exhibiting an allergic reaction, you might be looking for a safe way to relieve his or her symptoms. Many pet parents search for hydroxyzine dosage for dogs because hydroxyzine is a veterinarian-prescribed antihistamine that is used to treat itching, swelling, and other allergic symptoms in dogs.

Typically prescribed for humans under trade names such as Atarax and Vistaril, hydroxyzine dosage can also be used off-label in dogs to treat seasonal allergies, atopic dermatitis (eczema), hives, acute allergic reactions, motion sickness, vomiting, and even anxiety or stress-related issues.

Hydroxyzine binds to histamine receptors, preventing itching, swelling, runny nose, and other allergic symptoms. Some dogs also respond well to the sedative effect to treat anxiety or travel sickness. But the hydroxyzine dog dose varies depending on your dog's weight, size, age, health status and purpose of use, so it should only be used with veterinary supervision.

Here is a full guide to safe hydroxyzine dosages for dogs, uses, benefits, side effects (including drowsiness), safety tips and alternatives. Be sure to ask your veterinarian first before administering hydroxyzine or any other human drug to your dog, as some over-the-counter allergy medications may contain additional ingredients that can be toxic.

Disclaimer: This guide is for informational purposes only and is not a substitute for professional veterinary advice.
Always consult your veterinarian before giving Hydroxyzine or any medication to your dog.

Key Takeaways

• Hydroxyzine (Atarax, Vistaril) dose is an antihistamine prescription drug used for dogs to treat itchy skin, allergies, allergic reactions, dermatitis, eczema and motion sickness.
• Hydroxyzine drugs blocks the histamine H1 receptors to help alleviate swelling, itching, inflammation and allergy symptoms.
• Hydroxyzine dosage for dogs is an off-label human drug used in veterinary medicine, meaning it can be legally prescribed by veterinarians for dogs even though it is not approved by the Food and Drug Administration (FDA) for use in dogs.
• Hydroxyzine products for dogs are all human products, so be sure to read and follow your veterinarian's dosing and administration instructions.
• It's important not to use over-the-counter human hydroxyzine combination products, as some may contain toxic ingredients for dogs.
• Possible side effects can include sleepiness, dry mouth, constipation or sedation. Occasionally, dogs may also become hyperactive or have seizures.
• Special care should be taken with dogs who have certain conditions or are taking other drugs, so be sure to disclose your dog's medical history and concurrent medications to your veterinarian.
• If your veterinarian deems hydroxyzine inappropriate, they may recommend other antihistamines, new allergy drugs, steroids, allergy shots, supplements or changes to your dog's environment to minimise allergen loads.

Hydroxyzine Dosage Chart For Dogs By Weight

Standard Dosage: 1 mg per 1 lb of body weight

Dog Weight (lbs)	Total Dose (mg)	25 mg Tablets	50 mg Tablets
10 lbs	10 mg	0.5 Tablet (approx)	—
20 lbs	20 mg	1 Tablet (approx)	—
25 lbs	25 mg	1 Tablet	0.5 Tablet
40 lbs	40 mg	1.5 Tablets	—
50 lbs	50 mg	2 Tablets	1 Tablet
75 lbs	75 mg	3 Tablets	1.5 Tablets
100 lbs	100 mg	4 Tablets	2 Tablets

Important Administration Details

• Frequency: Typically given every 8 to 12 hours (2–3 times per day).
• Unit Conversion: If using kilograms, multiply the weight by 2.2 to find the weight in pounds before determining the dose.
• Veterinary Approval: Always confirm these values with your vet to ensure they align with your dog's specific health profile and medical history.

What Is Hydroxyzine Dosage for Dogs, and How Does It Work?

Veterinarians often prescribe the prescription antihistamine hydroxyzine to dogs for the treatment of allergies, itchiness, skin irritation, hives and atopic dermatitis. It can also be used for other animals, but in dogs it is used to treat itchy dogs with allergies.

Hydroxyzine for dogs by weight may be prescribed in different formulations, including hydroxyzine hydrochloride and hydroxyzine pamoate, or be custom-compounded as needed.

Hydroxyzine is approved by the US Food and Drug Administration (FDA) for use in humans under various brand names including Atarax® and Vistaril®, but not for use in animals. But it can be prescribed by veterinarians for dogs as an extra-label (off-label) drug.

Hydroxyzine drug for pets prevents the action of histamine, which is released from the body during an allergic reaction. Histamine is able to bind to H1 receptors, which can lead to itching, swelling, redness, runny nose, sneezing, watery eyes, rash and hives. Hydroxyzine binds to these receptors, blocking histamine from binding and relieving allergy symptoms.

Hydroxyzine dosage for dogs per pound or kg of dog body weight can also have a calming effect, so some dogs may experience sedation. Antihistamines do not work the same for all dogs and may be more effective for some dogs than others, depending on the condition being treated.

What Is Hydroxyzine Used for in Dogs?

Hydroxyzine dose for dogs per kg or pound is an antihistamine prescription drug that can be used in dogs to treat allergies, itchiness and irritation. It's approved for use in humans by the FDA, but can be used off-label in dogs.

It is used mainly to treat:

• Environmental and seasonal allergies - Relieves itching, redness, runny eyes and irritability.
• Atopic dermatitis (atopy / eczema) - To treat atopic dermatitis and chronic itching.
• Allergic reactions - Can be used for allergic reactions to bee stings, drugs, snake bites, and other allergens.
• Nausea and vomiting / vomiting - May be administered before travelling due to its antiemetic properties.

But hydroxyzine may also cause a calming effect, helping some dogs sleep better and itch less during the night. But it may not work for all dogs and pets with severe allergies may require stronger drugs or allergy treatment. Hydroxyzine should only be used under the guidance of your vet.

What Is the Typical Dosage of Hydroxyzine for Dogs, and How Is It Given?

The recommended dose of hydroxyzine for dogs is generally weight-based and should only be given under the supervision of a veterinarian. The general rule of thumb is 1 mg per pound (2 mg/kg) orally 2 to 3 times a day, but some veterinarians will prescribe dosages every 6 to 8 hours or every 12 hours depending on the condition to be treated and your dog's response.

Hydroxyzine can be tablet, capsule or liquid, and is administered orally. Doses will be lower for smaller dogs and higher for larger dogs. The veterinarian will determine the correct dose, dose frequency and length of treatment.

Key administration tips:

• Only use the product prescribed by your veterinarian. Human over-the-counter hydroxyzine products can have additional ingredients that are toxic to dogs.
• It is best to use hydroxyzine products containing only hydroxyzine unless otherwise recommended by your vet.
• Liquid hydroxyzine drugs for dogs should be thoroughly shaken and measured using a dosing syringe or other measurement tool.
• This may be either with or without food, as instructed by your vet and tolerated by your dog.
• Hydroxyzine given by mouth may begin to take effect within 1-2 hours, reach its peak at 3 hours and last between 8-12 hours.

If you forget to give a dose, give it as soon as possible, unless it's near the time for the next dose. Do not double the dose. Do not cease treatment abruptly unless advised by your veterinarian.

Hydroxyzine may be used long term, depending on your dog's situation. It is not recommended for pregnant or lactating animals unless veterinary approval is obtained.

What Are the Common Side Effects of Hydroxyzine in Dogs?

Sedation or drowsiness is the most common side effect of hydroxyzine for dogs. Some dogs will appear depressed, lethargic or less alert following the administration of the drug, and these effects may improve with time. Other dogs may be hyperactive, agitated or anxious.

Other side effects can include:

• Dry mouth and increased thirst
• Constipation or slow bowel movements
• Indigestion, nausea, vomiting or diarrhea
• Loss of appetite or interest in food
• Drooling
• Trouble urinating
• Dizziness, weakness or confusion
• Mood changes, such as being unusually tired or fidgety

Rare but more severe side effects include:

• Muscle tremors
• Low blood pressure
• Seizures (rare)
• Swelling of the face or trouble breathing (may be an allergic reaction)

Veterinarian hydroxyzine dosage for dogs can cause thirst and dry mouth, so make sure to provide plenty of water. Feeding your dog before administering the drug can help prevent gastrointestinal problems.

If side effects are severe, persistent or unusual, contact your veterinarian. If your dog experiences seizures, difficulty breathing, fainting, or severe changes in behaviour, call your veterinarian immediately. Hydroxyzine for dog itching should be used with caution in dogs with some medical conditions, or dogs taking additional medications and is not recommended for pregnant dogs.

What Are the Most Serious Risks of Hydroxyzine for Dogs?

There are potential serious side effects of hydroxyzine in dogs. Overdose and administration to dogs with certain medical conditions are probably the highest risks.

Main Serious Risks

• Seizures - A serious adverse event. Discontinue the drug and see a vet right away.
• Overdose - May include sedation, hyperactivity, ataxia (stumbling), weakness, hyperthermia (high body temperature), fainting or seizures.
• Excessive sedation - Some dogs may be very sleepy.

Dogs That Need Extra Caution

Hydroxyzine may not be ideal for:

• Pregnant or nursing dogs
• Older dogs
• Dogs used for work, as drowsiness can occur
• Dogs with allergy to hydroxyzine or cetirizine

Health Conditions That Can Increase Risk

Use with caution or avoid in dogs with a history of seizures, glaucoma, enlarged prostate gland, bladder obstruction, stomach obstruction, advanced heart failure, lung disease, thyroid disease, and severe liver and/or kidney disease.

Drug Interaction Warning

Hydroxyzine can enhance the side effects of sedatives, tranquilizers and some other drugs.

Important Note

Hydroxyzine(Dog allergy medication dosage) may need to be discontinued two weeks prior to allergy testing. Only use under the guidance of a veterinarian.

Does Hydroxyzine Interact With Any Other Dog Medications?

Hydroxyzine medication for dogs can interact with other drugs in dogs, so it should only be used with caution and under the supervision of a veterinarian. These can lead to increased side effects, like drowsiness, or decreased effectiveness of other medications.

Drugs That May Interact With Hydroxyzine

• Central nervous system (CNS) depressants (such as diazepam (Valium), alprazolam (Xanax), barbiturates and other antianxiety drugs), which may increase sedation
• Epinephrine - the effect of hydroxyzine may be reversed
• Anticholinergic agents - such as atropine or thorazine, which may have a synergistic effect
• Drugs that already make your dog sleepy or have a calming effect; this will increase sedation

Important Safety Guidance

• Never start or stop any medications, vitamins, herbal products or supplements without veterinary approval
• They may change the dose, frequency and medication to prevent interactions
• Never administer or discontinue any drug without your veterinarian's permission if your dog takes hydroxyzine

This ensures hydroxyzine will be safe and effective without drug interactions.

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FAQs

Final Thoughts

Atarax (brand name Vistaril) is a commonly used antihistamine in dogs for the treatment of itching, allergic reactions, dermatitis and motion sickness. While not approved for use in dogs by the United States Food and Drug Administration (FDA), it's commonly used by vets as an off-label allergy medication.

Side effects include drowsiness, although other mild side effects include dry mouth and lethargy. Seizures, among other severe side effects, can occur in rare cases, such as allergic reactions to the drug and overdose.

Be sure to follow your veterinarian's instructions and dosing and not change or mix medications without their advice. If you notice any adverse effects or changes in your dog's behaviour, consult your veterinarian.

Hydroxyzine Dosage For Dogs By Weight may be beneficial for some dogs, but it's not the only drug that can help with allergies. Your vet may suggest other therapies, depending on your dog's particular condition and severity, to ensure the best and most safe treatment for your pet.