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Diphenhydramine for Dogs – 7 Medical Uses

Diphenhydramine for dogs is an antihistamine used to treat motion sickness and the itch caused by mange, mites, and fleas. It can also be used to induce sleep, ease anxiety, and provide relief from general allergy symptoms.

Dosage of diphenhydramine for dogs is 2 – 4 mg of Benadryl per kilogram of body weight. This should be administered two to three times a day.  Weight, health conditions, and other medications can affect how well this medication will work.

Benadryl contains diphenhydramine.  If you decide to use Benadryl, please read the ingredients.  Look for the tablet or capsule form. 

Liquid Benadryl contains ingredients that can be harmful to your dog. Make sure there is no alcohol, acetaminophen, pseudoephedrine, or artificial sweeteners.  Xylitol is extremely toxic for dogs.

Diphenhydramine is also an active ingredient found in products like Anacin PM, Advil PM, Excedrin PM, Sudafed, and Robitussin, to name a few. 

These drugs contain other ingredients including acetaminophen and ibuprofen. Never give your dog anything with these ingredients. Your dog’s metabolism cannot process the drug and it becomes toxic in the body.

This is Why You Need to Be Careful When Choosing Diphenhydramine for Dogs

Choose a product like Benadryl which ONLY has diphenhydramine as the main ingredient. 

Added ingredients like acetaminophen, ibuprofen, alcohol, or xylitol (a sweetener), are toxic to dogs.  Consult with your veterinarian before administering over the counter medications to your dog.


Dogs who suffer from motion sickness are not fun to travel with. Dogs get motion sickness just like we do and, if you’ve ever had it, you know how miserable it is. 

The medication takes time to get into the dog’s system, so plan to administer at least a half hour to an hour before getting in the vehicle.

Diphenhydramine (in the form of Benadryl tablets or capsules) can be given to dogs. The appropriate dosage for dogs is 2 – 4 mg per kilogram of body weight.


Fleas are common in dogs and cats. If you see one flea on your dog, it’s safe to assume there are more.  Creams, lotions, gels, or diphenhydramine for dogs are good choices to ease itch, but they don’t solve the problem.

If your dog has fleas, make sure to see the veterinarian. Ask for a topical solution that can be applied between the shoulder blades. 

Topical flea prevention only works if you continue the treatment month after month. It takes at least 3 weeks for a flea to go through the life cycle. Each flea on your dog could be in a different life stage.  

Diphenhydramine for dogs is an antihistamine and antihistamines work to stop itch and inflammation. 

Number 3:  MANGE

Mange is normally found in puppies. Puppies are able to contract mange while nursing from their mothers. It can clear up on its own, but it can also become a full-blown problem.

Symptoms of demodectic mange include intense itching, patchy fur loss, skin infections, red and crusty sores (check the elbows, armpits, tummy, ears, abdomen and chest).

Diphenhydramine for dogs will help the itch and might even cause some drowsiness in your dog. 

An extremely itchy dog is an agitated dog.  Using diphenhydramine for dogs might help your dog sleep a little better.

Ask your veterinarian about diphenhydramine for dogs.  He/she will want to see your dog to check for signs of secondary skin infections.  Keep your dog’s immune system up with appropriate supplements.

Number 4:  Mites

Mites are a parasitic skin infection that can be very contagious. Dogs can get mites from the environment and from other dogs.

Mites can be transmitted to humans as well.

If your dog has what looks like “walking dandruff”, suspect mites.  Other symptoms include excessive scratching, lesions on back, scaling skin, skin flakes that look like dandruff, and fur loss.

The use of diphenhydramine for dogs to reduce itch is a good “quick fix”.

However, the product will not cure mites without further treatment. You will need to bring your dog to the veterinarian to confirm diagnosis.

Number 5:  Anxiety and Restlessness

If your dog can’t sleep, chances are you can’t either. 

The aggravation of severe itch will drive your dog to dig at his/her skin.  Signs of anxiety in a dog include pacing, panting, vocalizing, hiding, tail between the legs, and sometimes aggression.

Using a product like Benadryl could induce drowsiness and reduce the itch enough to give your dog relief. 

Diphenhydramine for dogs isn’t the only solution.  Dogs itch for many reasons. If it lasts for days and is causing sores on the skin, get your dog to a veterinarian ASAP.

Of course, the best situation is to get your dog to the veterinarian BEFORE your dog develops skin sores.

Number 6: Sleepy Time

There are times when your dog might need help with sleep. A healthy dog doesn’t need medication to induce sleep; however, a dog that has just come from surgery might. 

After surgery, your veterinarian might suggest that your dog take it easy for a few days.

It’s hard to stop them from biting at the site. Elizabethan collars aren’t always easy to keep on a dog either.

If your dog needs helping easing into sleep, diphenhydramine for dogs may help.  

Always check with your veterinarian first because other medications could interact with diphenhydramine.

Number 7:  Mild Allergies

If your dog has mild allergies that cause the sniffles, sneezing, or red eyes, Benadryl might be a good choice. 

Remember that diphenhydramine is an antihistamine. Antihistamines block the receptors that cause itch.

Dosage for dogs with allergies would be about 2 – 4 mg per kilogram.  You should also consider what might be causing the allergy. 

Wipe your dog’s feet after he/she has been on the grass. Bath your dog with anti-itch shampoo, and make sure to stay on top of flea eradication.

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