Medication Guide • Reviewed by Dr. Tiffany Delacruz, DVM
Hydroxyzine (Atarax) for Dogs
Hydroxyzine is a prescription antihistamine used in dogs for mild allergic itch, anxiety, and as part of allergy management plans.
What Hydroxyzine (Atarax) is used for in dogs
- Mild to moderate allergic itching
- Mild situational anxiety
- Adjunctive allergy treatment
How it works
Hydroxyzine blocks H1 histamine receptors more strongly than diphenhydramine (Benadryl). It also has mild anxiolytic effects through CNS serotonin activity.
Available formulations
10 mg tablet
25 mg tablet
50 mg tablet
Oral suspension
Side effects to know
Common side effects
- • Drowsiness
- • Dry mouth
- • Decreased appetite
These usually resolve on their own. If they persist past the first few doses, ask your vet.
Call your vet immediately if you see
- ⚠ Severe sedation
- ⚠ Tremors
- ⚠ Allergic reaction (rare)
Drug interactions
- • Other sedatives
- • CNS depressants
- • MAOIs
When not to use
- • Severe liver disease
- • Glaucoma
- • Urinary obstruction
Monitoring during treatment
First dose should be observed for 2-3 hours to assess sedation level. Adjust timing or dose with your vet.
Need a Hydroxyzine (Atarax) refill?
RexVet is the first 501(c)(3) non-profit online vet service in the U.S. Talk to a licensed veterinarian by video, get your dogs's Hydroxyzine (Atarax) prescription, and have it shipped through RexVetRx — all for $64.99 per visit.
Book a vet visit — $64.99Hydroxyzine (Atarax) for Dogs
Frequently asked questions
Hydroxyzine vs Benadryl for dogs?
Hydroxyzine is more potent and sometimes works in dogs who don't respond to Benadryl. It's prescription-only (vs Benadryl OTC) and may cause more sedation.
Will hydroxyzine help my dog's allergies?
For mild allergies, sometimes. Severe allergies typically need stronger treatment like Apoquel, Cytopoint, or short-term steroids. Hydroxyzine is often part of a multi-drug approach.
Can RexVet prescribe hydroxyzine?
Yes — for dogs with allergy or mild anxiety questions, a RexVet video visit can result in hydroxyzine through RexVetRx.
How long does hydroxyzine take to work?
Effects begin within 1-2 hours; maximum effect within 24-48 hours of consistent dosing for chronic use.
Is hydroxyzine addictive?
No — it's not a controlled substance and doesn't cause dependency.
Medical review by Dr. Tiffany Delacruz, DVM
Chief Executive Officer & Lead Veterinarian, RexVet. Licensed in Florida, New York, and Virginia.
Last fact-checked: 2026-05-19
Sources
This page is an educational reference and does not replace veterinary advice. Always consult a licensed veterinarian before starting, changing, or stopping medication for your pet.