Benadryl is a commonly used brand-name antihistamine that is the equivalent of the generic medication called Diphenhydramine. Diphenhydramine is often used in dogs for allergies and allergic-type reactions.  

While Diphenhydramine is generally safe and well tolerated, it is best to consult with your veterinarian before using this or any other over-the-counter medications, as it can be contraindicated in some situations.   

Once your veterinarian has recommended dosage for the use of Diphenhydramine, you can actually help stop your dog’s itching and allergy symptoms with this inexpensive over-the-counter medication.

When Diphenhydramine is used over the counter, it’s important to check the specific product, as some products with the name Benadryl may have other ingredients.  For example, some products may have phenylephrine for congestion, and this is toxic for dogs.  Again, if you are unsure if a specific product is safe, it’s best to consult with your veterinarian.

For the purpose of this article, we will use the more commonly known brand name Benadryl interchangeably with the generic name Diphenhydramine. And, when we use the brand name Benadryl, we are only referring to the product that does not contain other added medications.

 We will explain what Benadryl is, how it works, and what conditions may improve from its effects. We will also discuss typical dosages that your veterinarian might recommend,  as well as the risks of using it and important considerations before its usage.

Can I Give My Dog Benadryl?

Can I Give my Dog Benadryl

Yes, you can give your dog Benadryl as approved by your veterinarian. 

Benadryl is a commonly used medication used for a number of different conditions and symptoms – from seasonal allergies and motion sickness to insect bites and vaccine reactions Additionally, it is highly budget-friendly – generic Benadryl tablets cost about 2 cents each at

When Benadryl Can Be Beneficial For Your Dog

Benadryl can be used when dealing with a dog’s allergic reactions for symptomatic management. Additionally, because Benadryl can have sedative effects, it is sometimes used for anxiety.

For example, if your dog suffers from anxiety during fireworks with a noise phobia, giving it Benadryl before the celebration starts will prevent or lessen stress and keep your pup calmer and more relaxed. Some people use Benadryl to decrease anxiety with car rides as well.

If you are unsure whether it is safe to give your dog Benadryl and if they can benefit from regular or occasional use, do not hesitate to talk to your trusted veterinarian

Benadryl for Dogs
  • Relieves coughing, allergy symptoms and itching caused by insect bites
  • Can also be used as a sedative to treat motion sickness and anxiety
  • Helps treat muscle tremors caused by toxins or other medications

Benefits and Uses of Benadryl for Dogs

Benadryl is most commonly used to alleviate mild-to-moderate allergies in dogs and humans. However, diphenhydramine targets a range of different conditions and symptoms that your dog may be suffering from.

Benadryl for Allergies. Diphenhydramine helps to lessen or eliminate symptoms from allergic reactions, including hives, itching, coughing, sneezing, swelling, inflammation, runny nose, and watery eyes. 

Benadryl for Bites. Insect bites and stings (bee, wasp, spider) in dogs are painful and likely to cause local inflammation, which can be managed with Benadryl. Diphenhydramine is also beneficial for dogs experiencing anaphylactic reactions as it targets its chemical pathways. However, with true anaphylaxis, Diphenhydramine should be administered by injection from your veterinarian as it will work more rapidly. 

Benadryl for Anxiety. An important side effect of Benadryl administration on your dog is drowsiness. This side effect can be put to good use with some dogs as it can help to alleviate suffering from anxiety. For example, you can give your dog a single dosage of Benadryl to manage agitation caused by fireworks or thunderstorms. It is important to mention that a few dogs will actually experience agitation from Benadryl instead of relaxation.

Benadryl for Mast Cell Tumors. Diphenhydramine is also used as therapy medication for other conditions such as tumors. Benadryl has been known to help mitigate the effects of the massive histamine release that is caused by mast cell degranulation in mast cell tumors.

Benadryl for Motion Sickness. If your dog suffers from motion sickness during car and plane rides, Benadryl can help ensure a smooth and pleasant trip. 

Benadryl for Adverse Vaccine Reactions. Insect bites and stings aren’t the only things that can cause anaphylactic shock. Adverse vaccine reactions can have similar effects. Diphenhydramine, sometimes given for this by injection, can be used to counteract these effects and prevent potentially fatal anaphylaxis.

Potential Side Effects and Risks of Benadryl for Dogs

Potential Side Effects and Risks of Benadryl for Dogs

Every medication has the potential to trigger side effects and adverse reactions in dogs, and Benadryl is no exception. For a simpler understanding, we will classify the side effects of Benadryl into two categories: common side effects and rare side effects.  

The group of common side effects in dogs includes:

  • Dry mouth
  • Sedation
  • Agitation
  • Drooling
  • Changes in heart rate and respiratory rate

The group of rare side effects in dogs includes:

  • Vomiting
  • Appetite changes
  • Itchy skin

It is highly advisable to monitor your dog closely for the first 1-5 hours after administering the medication, as most side effects occur within this timeframe.  

It is also recommended to avoid giving your dog Benadryl in the first place if diagnosed with one or more of the following health issues and conditions:

Again, prior to giving your dog the medication, it always helps to check with your local veterinarian or clinic. The annual vet consultation is also a perfect time to talk about Diphenhydramine use and dosage for your dog. 

Finally, while uncommon, Benadryl can trigger allergic reactions in sensitive dogs. In such cases, a quick trip to the vet’s office is warranted. Since Benadryl is used to treat allergies, the dog’s allergy symptoms will worsen in case of sensitivity to the medication. 

Common Benadryl Dosage for Dogs

The exact Benadryl dose for your dog depends on its size and what other medications it may already be taking. To determine your dog’s Benadryl dosage, talk with your trusted vet. A commonly use dosage range in dogs is 1 to 2 mg per pound.

When using Benadryl for your dog, it is critical not to exceed the recommended dosage. Too much Benadryl per pound of body weight can result in an overdose. Diphenhydramine overdoses manifest with pronounced excitability of the central nervous system and include signs and symptoms like:

  • Dilated pupils
  • High blood pressure
  • Rapid heart rate
  • Agitation or extreme lethargy
  • Severe Constipation or diarrhea
  • Vomiting
  • Excessive drooling

Once you have consulted with your veterinarian and they recommend a dosage of Benadryl that is safe to give to your dog, it is time to put that knowledge into practice and administer the medicine. It is best to give your dog Benadryl with food or after a meal. 

If your dog is reluctant to take a tablet, it’s fine to put it in their food or use a pill pocket

Benadryl for Dogs Usage Guidelines

Benadryl is available in different forms (tablets, liquids) and in various formulations. In terms of form, avoid liquid Benadryl for your dog. This is because liquid medicines have high alcohol contents, which can be toxic to dogs. 

As mentioned previously, make sure the tablets you are using contain strictly diphenhydramine and nothing else. For example, sinus medicines contain diphenhydramine but also feature additional active ingredients that are dangerous to dogs. 

Benadryl can also interact with certain medications, so it is important to tell your veterinarian what medications your dog is receiving when asking if it is okay to administer Benadryl. Several medications can interact with Benadryl, and these can include:

  • Anticholinergic drugs
  • Tricyclic antidepressants
  • Sedatives
  • Anesthetics
  • Pain medications

If your dog is receiving some of these medications or has a condition that prevents it from using Benadryl, such as glaucoma, it is advisable to ask your veterinarian which alternatives are safe for your dog.

Some dog owners may want to try CBD Oil for symptomatic care. However, as CBD is not currently regulated, it’s best to ask your veterinarian prior to using something like CBD. One resource that you can ask your vet about if your dog cannot take Benadryl is Honest Paws, as they sell supplements that may help decrease symptoms associated with allergies or anxiety.

Honest Paws has high consumer ratings, is certified with the National Animal Supplement Council, and offers natural products that are tested to ensure superior quality.

Our Final Thoughts on Benadryl for Dogs

Benadryl for dog allergies

Benadryl is often safe for dogs and can be used to manage different conditions and issues. However, not all dogs benefit from this medicine. In fact, in some cases, it might be counteractive to use diphenhydramine. 

To keep your pup healthy and be a responsible dog parent, always consult with your trusted veterinarian before adding a new medication to your dog’s healthcare regimen. Keep in mind that this article is purely informative and not a substitute for professional vet advice. 

Dr. Lisa Steinberg say, “Diphenhydramine, which is the generic medication in Benadryl, is cheap and easy to obtain for pet dogs. While Benadryl is sold over the counter, it is always vital to ask your veterinarian if any over-the-counter medication or supplement that you want to use is safe, as sometimes they can be deleterious to their dog. 

Benadryl is commonly recommended for allergy symptoms such as itchy ears and skin, as well as for anxiety for noise phobias and car rides. It is possible that Benadryl alleviates itch as an antihistamine but also because it makes dogs sleepy, so the itch doesn’t bother them anymore.”