Benadryl for Dogs

Benadryl for Dogs: Recommended Dosage, Side Effects, and More

Katelyn Son
By Katelyn Son
Medically reviewed by Ivana Crnec, DVM
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Benadryl’s active ingredient, Diphenhydramine HCl, is very safe and effective on dogs. You can actually help stop your dog’s itching and allergy symptoms with this inexpensive and over-the-counter medication.

In this article, we will talk about Benadryl for dogs. We will explain what Benadryl is, how it works, and what conditions may benefit from its effects. We will also discuss the right dosage and go through the risks and usage considerations. 

Can I Give My Dog Benadryl?

Can I Give my Dog Benadryl

Yes, you can give your dog Benadryl. Diphenhydramine HCL (brand name Benadryl) is an over-the-counter medication from the antihistamines group. 

Benadryl is an all-around type of medication and can be also used for a number of different conditions and symptoms – from seasonal allergies and motion sickness to insect bites and vaccine reactions. 

Plus, it is highly budget-friendly – generic Benadryl tablets cost about 2 cents each at

When to Use Benadryl for Dogs

You can use Benadryl when dealing with a dog’s allergic reaction for symptoms management. Alternatively, you can use this medicine to prevent certain scenarios for your pup. 

For example, if your dog suffers from anxiety during fireworks, giving it Benadryl before the celebration starts will prevent stress and keep your pup calm and relaxed. 

If you are unsure whether your dog can benefit from regular or occasional Benadryl use, do not hesitate to talk to your trusted veterinarian

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Benefits and Uses of Benadryl for Dogs

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

Benadryl for Allergies. Diphenhydramine’s purpose is to eliminate the allergy symptoms like 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. 

Benadryl for Anxiety. The main side effect of giving your dog Benadryl is drowsiness. This side effect can be put to good use or, better said, to help dogs suffering from anxiety. For example, you can give your dog a single dosage of Benadryl to manage agitation caused by fireworks or thunderstorms.  

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. This effect can be linked with the diphenhydramine’s ability to calm the dog down and make it more sluggish.

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. Benadryl 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, and Benadryl for dogs 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
  • Urinary retention
  • Sedation
  • Hypersalivation
  • Increased breathing rate 
  • Rapid heart rate 

The group of rare side effects in dogs includes:

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:

Basically, if you are unsure whether you should give your dog the medication, it always helps to check with your local veterinarian or clinic. The vet consultation is also the perfect time to talk about Diphenhydramine dosage for your dog. 

Finally, 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. 

Benadryl Dosage for Dogs

The exact Benadryl dose for your dog depends on its size. To determine your dog’s Benadryl dosage, talk with your trusted vet. Alternatively, you can follow these guidelines:

  • 30 Ibs or smaller – 10 mg per dose or 1/2 adult Benadryl tablet  
  • 30-50 Ibs – 25 mg per dose or 1 adult Benadryl tablet 
  • over 50 Ibs – 50 mg per dose or 2 adult Benadryl tablets 

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
  • Seizures
  • High blood pressure
  • Rapid heart rate
  • Agitation
  • Constipation

Once you are aware of the importance of giving your dog the right Benadryl dosage, it is time to put the knowledge into practice and administer the medicine. It is best to give your dog Benadryl on a full stomach. 

Since most dogs are naturally inclined to refuse tablets, it is a good idea to break the medication and put it in your dog’s 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 for formulations, 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 such as:

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

Suppose your dog is receiving some of these medications or has a condition that prevents it from using Benadryl, for example, prostate enlargement. In that case, it is advisable to look into alternatives such as CBD oil.

CBD products are not only safe for dogs, but they can also be used to help relieve occasional discomfort, assist the immune system, promote long-term health, and support healthy skin.

Our top pick is the Honest Paws CBD Oil for Dogs. This company has high ratings with the Better Business Bureau, is certified with the National Animal Supplement Council (which not many pet CBD companies are), and offers organic, all-natural products that are always lab-tested to ensure the highest quality.

With over 1,000 glowing reviews on their website, it’s easy to see why so many pet parents are turning to CBD to help their dogs live healthier and happier lives!

Our Final Thoughts on Benadryl for Dogs

Benadryl for dog allergies

Yes, Benadryl is 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.