Get

In Your Inbox

Dogster is reader-supported. When you buy via links on our site, we may earn an affiliate commission at no cost to you. Learn more.

Benadryl for Dogs: Our Vet Explains Safety & Effectiveness

Share

Cute dog waiting for pill from owner hands

A common antihistamine in households is Benadryl or diphenhydramine. It is a medication that pet parents readily have access to and quickly reach for to help with their pet’s ailments. But is Benadryl really helpful? What can it be used for? Do I need my vet’s permission to use it on my dog? Continue reading below to learn more about Benadryl and how it can be administered to your pup.

divider dog faces oct 2024

What Is Benadryl?

Benadryl (Banophen, Vetadryl, Diphenhist) is an antihistamine medication labeled for humans. Off-label use of Benadryl has been extended to several species for numerous conditions. Diphenhydramine is also available as Vetadryl, a veterinary-specific product.

Benadryl has been used in dogs to help combat pruritus, or itchiness, associated with allergies. There is debate regarding whether Benadryl improves pruritus or just reduces the clinical signs of itchiness through sedation. Benadryl is commonly used in animals diagnosed with mast cell tumors to block histamine released by the tumor, which can cause inflammatory signs.

Benadryl is also used for allergic reactions and hypersensitivity cases, including insect stings and vaccine reactions. It can help prevent allergic reactions, including anaphylaxis. Diphenhydramine can be used as an antiemetic and is helpful to patients with vestibular disease.

Bendaryl
Image By: EHStockphoto, Shutterstock

How Is Benadryl Administered?

Benadryl is typically administered orally as a liquid, pill, or capsule. An injectable formulation is also available for use in hospitals. Benadryl should not be administered intravenously. However, we recommend not giving your dog any unless it is under the instructions and guidance of your vet.

Benadryl can often be combined with dyes and flavors to make it more appealing to humans. Care should be taken to ensure that flavored tablets or liquids do not contain xylitol, an artificial sweetener that is harmful to veterinary patients. Additionally, care should be taken to avoid combination products without consulting your veterinarian.

Again, before administering any medication to your pet, consult your veterinarian. Diphenhydramine is dosed in dogs at 2–4 mg/kg every 8–12 hours, according to the Merck Veterinary Manual.1

Before giving any new medication to your dog, we recommend you consult a veterinarian for the best advice on which would be the best treatment for your pup.

If you need to speak with a vet but can't get to one, head over to PangoVet. It's our online service where you can talk to a vet online and get the advice you need for your dog — all at an affordable price!

PangoVet_Mention-in-Content Savings V1

What Happens if You Miss a Dose of Benadryl?

If you skip a dose, you can administer the Benadryl dose later, but be sure to wait the appropriate amount of time before taking the next dose. Avoid doubling the dose since it can cause sedation.

Dog Pill Mouth
Image Credit: Jeanette Virginia Goh, Shutterstock

Potential Side Effects of Benadryl

  • Drowsiness
  • Dry mouth/Dry Eyes
  • Urinary Retention
  • Gastrointestinal signs
  • Tachycardia (elevated heart rate)

Contraindications

Although viewed as a safe medication, there are medical conditions and potential drug interactions that may not make Benadryl a good option for your pet. Diphenhydramine use in working dogs may temporarily hinder job performance due to sedation.

Below are some contraindications to the use of Diphenhydramine. Diphenhydramine use should be avoided or used cautiously in patients with:

  • Difficulties urinating
  • Asthma attacks
  • Liver disease
  • Seizure disorders
  • Cardiovascular disease
  • Hypertension
  • Hyperthyroidism
  • Asthma and COPD
  • Closed-angle glaucoma

Possible drug interactions may also occur if administered concurrently with CNS depressant drugs and MAO inhibitors.

cute sick dog waiting for the vet
Image Credit: Utku Demirsoy, Shutterstock

divider dog faces oct 2024

Frequently Asked Questions (FAQ)

Is Benadryl Safe to Use in Pregnant Dogs?

It is unknown if Benadryl should be used in pregnant animals. As a precaution, it should be avoided if possible.

Should I Use the Veterinary Diphenhydramine, Vetadryl, Instead of Benadryl?

Either product can be used. However, due to the available doses, dosing with Vetadryl may be more convenient in some cases.

Should Diphenhydramine Be Given Every 8 or 12 hours?

This medication can be dosed at either interval. The dosing interval is determined by the condition being treated and the patient’s response to therapy.

Young veterinarian with medical document touching dog neck and cuddling it during appointment
Image By: Pressmaster, Shutterstock

divider dog faces oct 2024

In Summary

Diphenhydramine, otherwise known as Benadryl or Vetadryl is a good medication to have on hand. It has several uses and can be used in many illnesses. As with any medication, it is important to discuss the dosing recommendations with a veterinarian prior to use, especially if the patient has concurrent illnesses or is taking other medications.

See also:


Featured Image Credit: Billion Photos, Shutterstock

Want content like this delivered to you?

Sign Up For Our Newsletter

News, insights, expert advice, and everything dog

* By submitting, you agree to our Terms & Conditions and Privacy & Cookies Policy.




How useful was this post?

Click on a star to rate (you can leave written feedback after clicking submit)

Help us improve Dogster for pet parents!

Your feedback really matters.

What did you like about this post? Also how can we improve it?

Join the conversation

Leave a Reply

You’re very welcome to leave a comment or question. Please know that all comments must meet our community guidelines, and your email address will NOT be published. Let’s have a positive and constructive conversation.


Talk With A Vet Online

Peace of mind,
anywhere, anytime

Affordable vet advice

We Didn’t Just Add a Dog to Our Life – We Built a Life With Him

“We didn’t just bring a dog home—we built a life together.” Most people are quietly taught a version of pet ownership that looks...

What Most Airlines Won’t Let You Do With Your Dog (Even If You Pay Extra)

Airline pet policies are notoriously hard to navigate. The information is scattered across different pages, buried in FAQ sections, and often contradicts what...

Designer Breeds: Best of Both? New Study Says No

“I’ll take a highly trainable, low-shedding lapdog, hold the heart disease and anxiety!” Something I always found amusing was when people would point...

Ask Dr. Paola- Help! My Dogs Erection Gets Stuck! (April 6, 2026)

Welcome to our “Ask Dr. Paola” series, where every Monday we bring expert advice straight from Dr. Paola Cuevas (MVZ) to help our...

More related

Can Dogs Smell Sickness? Vet-Verified Facts

Dogs are incredible animals, and their relationship with humans goes much further than just owner and companion. They have been used by police...

How Long Is Kennel Cough Contagious? (Vet Answer)

Kennel cough is a mild, infectious disease that is highly contagious. Groomers, boarding facilities, and other places where dogs are in tight quarters...

What Happens to Police Dogs When They Retire? Facts About Canine Retirement

Dogs play a big part in helping many local or national police forces maintain order and the rule of law. They even serve...

Life’s Abundance Dog Food vs. Blue Buffalo 2026: Pros, Cons & What to Choose

There are a surprisingly high number of dog food brands out there. Plus, each brand has different recipes, which all contain different ingredients...

Keep reading

Can Dogs Eat Brownies? Vet-Approved Facts, Risks & FAQ

Brownies have long been an American favorite for those who love sweets. They are gooey, sweet, and filled with chocolaty heaven. For dog owners, we’re sure there has been a time when your dog stared at you longingly because they...

Can Dogs Eat Brownies

Wellness Dog Food vs Blue Buffalo: Pros, Cons & What to Choose

One of the most frustrating moments as a pet parent is when you’re sitting there scratching your head over which food is better for your dog—especially when every brand claims to be the best! Two popular dog food brands vying...

Dogster_Dog Food Wellness VS Blue Buffalo

Can Dogs Eat Tater Tots? Vet-Approved Facts & FAQ

Chances are that you didn’t feed your dog tater tots on purpose, but if they got into a few that were left out, what should you do? Are tater tots toxic for dogs, and if you do have a few...

Can Dogs Eat_Tater Tots

Why Does My Dog Poop on Concrete? 8 Potential Causes

Your daily walks with your dog are usually pleasant experiences. You meet other people and their pups, exercise, and enjoy the fresh air. Even when you’re a responsible owner who carries poop bags to collect the waste, your dog may...

woman throwing dog poop

Inukshuk Dog Food Review 2026: Pros, Cons, Recalls & FAQ

Inukshuk is not a brand that most people are familiar with, but we hope to change that! Inukshuk dog food is for very active dogs. They have four recipes, which vary in the percentage of protein they offer. Therefore, you...

Dogster_Inukshuk Dog Food Review

10 Best Dog Foods for Bichon Frises in 2026 – Reviews & Top Picks

There are a few things to consider when looking at reviews for the best dog food for Bichon Frises. Keep in mind that a few of these options include ingredients for specific diets that are not required unless specified by...

Bichon eating

Can Dogs Eat Elderberries? Vet-Verified Facts & FAQ

The use of elderberries in human remedies has been on the rise over the past few years. You’ll find elderberry cough syrup on drug store shelves and elderberry jams and jellies floating around the grocery aisles. Not to mention, elderberry...

Can Dogs Eat_elderberries

Can Dogs Eat Chorizo? Vet Approved Nutrition Facts & Risks

Chorizo is a spicy sausage that most of us love, and when we love something as pet owners, we sometimes want to share it with our pets. However, there are some foods you shouldn’t share with your pet, and chorizo...

Can Dogs Eat_chorizo

Love Dogs? So Do We! Join the Dogster Community

Stay informed with expert pet care insights delivered straight to your inbox! Discover professional guidance on animal behavior, feeding tips, trusted product picks, and much more.




Sign up for the Dogster Email Newsletter