Best (and Safest) Allergy Medicine for Dogs

Published November 30, 2021
An adult beagle dog on the couch

Addressing canine allergies can take some trial and error. Based on the root of your dog's allergies and their medical condition, your veterinarian may recommend a few medications or a variety of options for treatment. Each comes with pros and potential cons. Familiarize yourself with the available allergy medicines for dogs to discover which may be the best fit for your pet.

Supplements for Allergy Support

Supplements designed to promote skin or gut health can aid in allergy management. These are most often used in combination with an allergy medication. Some owners prefer to try this approach before turning to other forms of allergy management.


The relationship between gut and skin health has been widely researched -- even in dogs. Studies suggest that probiotics could reduce the severity of allergic skin symptoms. These beneficial bacteria can also aid dogs with digestive issues. Dozens of veterinarian-approved probiotic supplements are available in various forms (powder, capsule, paste, etc.). Some pet owners prefer to add a small amount of yogurt to their dog's food.

Fatty Acids

Fatty acid supplements such as fish oil can be very useful in allergy management. These fatty acids improve skin and coat health and have anti-inflammatory properties that may improve skin allergy symptoms. In addition, they're helpful in promoting a healthy heart and joints. Choose a canine-specific supplement containing omega-3 and omega-6 or ask your vet about dosing for over the counter products. Picking a fish-based diet or supplementing your dog's food with fish could also be a great way for them to obtain these beneficial fatty acids.

Antihistamines for Canine Allergies

Antihistamines are a mainstay in relieving the symptoms of allergies. Your veterinarian may prescribe one of the following human allergy medicines for your dog. Their choice depends on the type of allergies your pet suffers from, their medical history, existing conditions, side effects, and contraindications with other medications. Each has a unique dosage and dosing frequency.

  • Cetirizine: brand name: Zyrtec
  • Chlorpheniramine: brand name: Aller-chlor
  • Diphenhydramine: brand name: Benadryl
  • Fexofenadine: brand name: Allegra
  • Hydroxyzine: brand name: Atarax
  • Loratadine: brand name: Claritin
dog taking medication

Safe Use of Antihistamines for Dogs

It's important to note that while some of these drugs can be found over the counter, this doesn't mean you should readily medicate your dog with them. Most human medications are considered "off label" or "extra label" for use in animals. They can have adverse effects and should only be used under the guidance of your veterinarian.

If your vet gives you the OK, you'll want to make sure you get the correct medication. Many products today are specially formulated to be sugar-free, extended release, or include decongestants. Most of the added ingredients are toxic to dogs. Get a product that contains only the active ingredient and avoid formulas with the following additives.

  • Phenylephrine
  • Acetaminophen
  • Xylitol
  • Any liquid medication with alcohol

Prescription Allergy Relief

Although antihistamines work for some cases, other mechanisms of action may be necessary to address allergies. Various prescription therapies are available.


Apoquel is a newer oral drug designed specifically for use in itchy dogs. Unlike some other medications, it begins working very quickly and can relieve symptoms as soon as four hours after administration. This medicine is typically given twice daily for the first two weeks of treatment to get the itching under control, then every day thereafter for maintenance. Dogs under 1 year old cannot use Apoquel.


Oral cyclosporine therapy may be used for skin allergies in humans and dogs. The canine-specific product is known by the brand name Atopica. This immunosuppressant drug reduces itching and licking or itchy skin by inhibiting the immune system. It's typically given long-term and routine blood work monitoring is recommended. Pet owners must wear gloves while administering this medication to avoid adverse effects.


Cytopoint is a unique medication. It is not oral like many other allergy medicines -- it's injectable. And it is not technically a pharmaceutical -- it's classified as a "biological therapy." It contains antibodies that work to neutralize proteins that trigger your dog's allergies. This treatment does come with a hefty price tag, but a single injection can provide your dog with up to eight weeks of itch relief, so it's often well worth it. There are no significant side effects associated with Cytopoint, aside from the effects on your wallet.


Steroids are a naturally occurring hormone, but synthetic formulas can be used to suppress inflammation in allergic dogs. Your vet may prescribe a short, tapering course of oral corticosteroids to get your dog's symptoms under control, or they may recommend long-term therapy. Steroids do have side effects including increased appetite, increased thirst, excessive urination, and panting. When given for long periods of time, this drug can lead to diabetes, urinary tract infections, thin fur, and inhibited healing. Steroids should never be stopped abruptly.

The Best Allergy Medicine for Dogs

Dogs can be allergic to numerous elements: food, dander, fleas, grass, dust, and mold, among others. It's difficult to say which medication is classified as the "best." Each dog is unique, and the root of their allergies could be vastly different. Together with your veterinarian, you can weigh the pros and cons of each allergy medicine to find the best option for your dog.

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Best (and Safest) Allergy Medicine for Dogs