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dog scratching

the itch is real

The essentials

  • Yes, most dogs can take Benadryl. But there are a few scenarios and medical conditions where giving your dog Benadryl could be harmful.
  • The right Benadryl dosage for dogs is based on body weight. Our vets recommend 1-2 mg per pound of your dog’s body weight.
  • Human medications are usually unsafe for dogs. Benadryl, however, is the exception. The children’s Benadryl in your cabinet is perfectly safe for your pet.

Is Benadryl safe for dogs?

It’s incredibly common for dogs to have allergies. The good news is that the same Benadryl that’s in your medicine cabinet can work wonders for canines too. Although it’s not yet been approved by the FDA for use in animals, it’s fairly common for veterinarians to suggest giving your dog a dose of Benadryl to counteract the symptoms of seasonal allergies, environmental allergies, food allergies, integumentary diseases (skin-related conditions) and one-off allergic reactions.

The correct dosage of Benadryl

Although there are factors like pre-existing conditions and breed type that may come into play (consult with your vet), the Merck Veterinary Manual suggests the right dosage is 1-2 mg of Benadryl for every pound of body weight. Give your dog the proper dosage twice daily for the best results.

So, if you have a 25-pound dog, start with the low-end dose of 25 mg and observe the results. If you don’t see an obvious difference in the next 30 to 60 minutes, try the high-end dose of 50 mg at the next interval

Always start with the low-end dosage. Diphenhydramine is an older generation antihistamine so a side effect is drowsiness. Most of my patients are like zombies when they get the high end of the dose range!

Erica Irish, DVM

betterpet Advisor

Give your dog the Benadryl tablets, not liquid Benadryl caplets. Benadryl comes in 25 mg tablets, which makes it easier to get closer to the exact dosage you need when preparing them for your pet, as opposed to the liquid caps. Plus, they’re easier to break in half for smaller dogs.

Benefits of Benadryl for dogs

The reasons you’d consider giving your dog a dose of Benadryl are similar to the reasons you’d give it to a person:

  • Symptoms of allergies (sneezing, redness of eyes, watery eyes, itching)
  • Reaction to an insect bite or bee sting; facial swelling, difficulty breathing
  • Skin allergies (redness, itchy skin, inflammation, hives)

Since Benadryl is an antihistamine, it works by blocking the naturally occurring histamines in your dog’s body and some of the symptoms it causes. (Benadryl is the brand name for diphenhydramine HCl, which is the active ingredient.)

Keep in mind that when taken by mouth, it takes about 15 to 30 minutes to begin working. If your dog is experiencing some extreme sneezing or itching, it will take a bit of time before they’ll get relief. Don’t rush to give your dog a larger dose until sufficient time has passed for the Benadryl to start working.

Can I use Benadryl to calm my dog before a trip?

Never use Benadryl to treat motion sickness and travel anxiety in dogs. Yes, it can make your dog sleep, but the drug is not intended for this use.

We’ve all been there — it’s time for a car ride and your dog won’t stop fussing in the back seat. Maybe it’s their first time flying in a carrier and they’re having trouble getting comfortable or being still. Just know that Benadryl won’t address the root problems of motion sickness or anxiety.

Instead of drugging your dog to sleep, we recommend Cerenia (maropitant) or Dramamine for motion sickness. Some dog owners swear by CBD, though we’re still waiting for science to catch up. Ask your vet about anxiety treatments before your next road trip. 🚙

👉 Here’s everything you need to know about CBD use in dogs

👉 Learn more about Dramamine for dogs

Common side effects of Benadryl

As with any other drug, there can be side effects. Benadryl can have side effects in humans, not just dogs, so before giving your pup a dose, consider what some of the negative effects can be:

  • Drowsiness
  • Dry mouth

These are signs that Benadryl is probably not the best solution for your dog. Additionally, make sure to check with your vet before giving your dog any Benadryl if they have pre-existing conditions like:

  • Glaucoma
  • Heart failure
  • Lung disease
  • Prostatic hypertrophy

Benadryl can cause adverse reactions in dogs that have these conditions and those that are similar. One final thing to note is that if your dog is pregnant, it’s unlikely your veterinarian will give you the go-ahead to give them Benadryl at all.

dog itching

always consider your dog's health before deciding to medicate with Benadryl

How do I know if my dog is having an allergic reaction to Benadryl?

Similar to side effects, the signs of a severe allergic reaction to Benadryl will look like the following:

  • Rapid heartbeat
  • High blood pressure, elevated heart rate
  • Dilated pupils
  • Agitation
  • Vomiting
  • Diarrhea

🚨 If you suspect your dog is having an allergic reaction to Benadryl, contact your vet or bring them to an emergency veterinarian hospital right away.

Although it’s unlikely your dog will experience adverse effects from Benadryl, it’s important to be aware that they are a possibility. Since there are over-the-counter alternatives, if your dog’s symptoms are relatively mild, you may be better off skipping the Benadryl altogether.

If your pet’s suffering from the springtime snuffles, it’s likely more than okay to give them a small amount of Benadryl for relief on occasion. However, we always recommend consulting with your veterinarian before giving your dog a dose of anything new.

Over-the-counter alternatives and natural remedies

If your dog struggles with allergy-related conditions like atopic dermatitis, consider a few of these OTC alternatives that can help make a small dent in your dog’s symptoms.

Quercetin. Quercetin is a flavonol found in many fruits and vegetables that has positive anti-inflammatory qualities. Foods like kale, spinach, blueberries, and strawberries are all rich in quercetin and safe to feed your dog.

Turmeric. The anti-inflammatory qualities of turmeric are well-documented in humans, but they’re just as real with dogs, too. The best part is that it’s more common than ever now to find special pet treats specifically made with turmeric (no need to get messy with turmeric powders).

Baking soda. Funny enough, you can use a basic paste of baking soda and water to treat a red, itchy spot of skin on your dog. Leave the paste on for a few hours before washing clean, and do your best to keep it covered to prevent licking

👉You can also try to soothe your pup’s allergies with Ready Pet Go’s Allergy Dog Supplement for doggies, made with natural ingredients.