Benadryl For Dogs: 10 Important Facts To Know

Dogs are such adorable creatures – fun-loving, active, and always up to some other mischief. This is bound to get them into certain non-serious troubles, which may cause them to have allergy 1symptoms.

The history of dogs dates back to ancient times when they were first domesticated from wolves. It is believed that this process began over 15,000 years ago when humans began to tame and breed wolves for their hunting skills. Over time, these wolves evolved into the various breeds of dogs that we know today.

1. Benadryl For Dogs

Benadryl is an antihistamine2 medication that can be used to treat a variety of allergies and allergic reactions in dogs, including itching, hives, and swelling. However, before giving your dog Benadryl, it’s important to consult with a veterinarian3 to determine the proper dosage and to rule out any underlying health issues.

The recommended dosage of Benadryl for dogs is typically 1 mg per pound of body weight, given two to three times per day. However, this dosage can vary depending on the size, age, and health of your dog, so it’s important to consult with a veterinarian first.

It’s also important to note that some dogs may have adverse reactions to Benadryl, such as drowsiness, dry mouth, or urinary retention. If you notice any unusual symptoms after giving your dog Benadryl, contact your veterinarian immediately. Additionally, Benadryl should not be used as a long-term treatment for allergies in dogs, and should only be used under the guidance of a veterinarian.

Pollen and other allergies in dogs
Photo by Angel Luciano on Unsplash

2. Allergies In Dogs

Allergies in dogs can vary from occasional and uncontrolled itching or something serious such as inflammation.

While many allergic reactions may sometimes go away on their own with patiently given time, your delightful buddy does not need to suffer that long.

Taking some medication during an allergic reaction is comparatively a smoother process when it comes to humans – we can speak out our troubles in clear language. However, it does not seem the case when it comes to dogs – their system is susceptible, and any carelessness can cause adverse effects.

jamie street MoDcnVRN5JU unsplash scaled
Photo by Jamie Street on Unsplash

Human drugs work very differently than drugs specifically made for dogs and other animals. Humans and animals have different internal systems and a difference in the mechanism to some extent.

It is always a piece of obvious advice to first get your trusted vet’s opinion on matters related to your dog’s health and then follow their advice.

One such medication which usually works well for both humans and animals, specifically dogs, without any worries, is Benadryl for dogs.

3. Is Benadryl For Dogs Safe?

Benadryl For Dogs?  Dr. Dan Explains

Benadryl has been chiefly considered safe and effective for dogs, given that it is given in the correct quantity and according to the veterinarian’s guidelines.

If you are giving Benadryl to dogs for the first time, keep a keen eye on your dog’s activity to note downside effects and take immediate action if needed.

Keep in mind that Benadryl or any fast-acting medication starts to work usually within one to two hours after consumption. The medication’s maximum efficacy is reached a little later than an hour. If you and your dog plan on having an outing or have some activity planned, make sure to time this with the medication’s effectiveness. This is due to the fact that dog Benadryl may make your pet a little tired.

Hence, it is also often used by pet owners when their dog is anxious or stressed out – but please keep in mind that this is not why the medication was formulated.

4. When Should You Consider Benadryl For Dogs?

While Benadryl is considered safe to consume for dogs and other animals, it is still of utmost importance to first gather essential veterinary advice. Benadryl dosage is commonly advised for mild symptoms.

Following are the instances when you can use Benadryl dosage 4for dogs:

4.1. Redness

Specific allergic reactions caused by insect bites can cause redness at the affected spot.

4.2. Inflammation And Swelling

Allergies to a particular food or environmental conditions can cause inflammation and swelling.

4.3. Sneezing

Sneezing, accompanied by a runny nose and teary eyes, can happen when your dog comes in contact with dust, pollen, or any such irritant particle that the dog has sniffed on. This is generally a kind of environmental allergy.

4.4. A Possible Anaphylactic Reaction

Anaphylaxis is a severe allergic reaction when exposed to an allergen. Its symptoms involve vomiting, weak or rapid pulse rate, rashes, and high blood pressure.

This is one of the life-threatening allergy symptoms which need immediate medical assistance.

5. Dosage Of Benadryl For Dogs

Benadryl Dosage For Dogs Guide

The quantity of dogs Benadryl depends upon their body weight – for instance, a chihuahua will require a lot less of a dosage than a full-grown Labrador or German Shepherd would.

Benadryl comes in different forms – liquid Benadryl, Benadryl tablets, children’s formula, which are chewable, and more.

Following is the dosage information varying with different forms of Benadryl:

5.1. Benadryl Tablets

The appropriate dosage of Benadryl tablets is 2-4 mg per dog’s weight. For example, if your dog weighs about 12 pounds, you will require to give a 12 mg dose in the morning, afternoon followed by another one in the evening.

Commonly, Benadryl pills are 25 mg, which will be sufficient for a 25-pound dog. However, if your dog is smaller in size, you can opt to take children’s chewable tablets, as they are about 12.5 mg.

5.2. Liquid Benadryl Medication

Benadryl comes in liquid form as well, which can be given. However, do not use liquid dog Benadryl if the ingredients contain sodium and alcohol.

Please talk to your dog’s vet before giving liquid Benadryl to your dog, as these are not absorbed the same way as the pills are.

6. What To Do In Case Of Benadryl Overdose

While a severity such as this should be avoided, pet owners must be aware of what an overdose of Benadryl appears like so that they can take the necessary steps to tune them down.

Signs which show symptoms of Benadryl overdose are:

  1. Extreme excitability to the point that it seems fatal and agitation
  2. Constipation
  3. Dilated pupils
  4. Seizures

If any of these symptoms are shown by your dog after consuming Benadryl, please immediately take your dog to the vet. Some of the dogs may even show these signs due to being allergic to Benadryl itself.

Get a vet's help in case of adversity
Photo by Lydia Torrey on Unsplash

7. Common And Rare Side Effects Of Benadryl

It is important for dog owners to monitor their dogs after giving them Benadryl. Most of these can be observed within an hour or so after giving the dose.

Some of the common side effects are:

  1. Urinary retention
  2. Dry mouth
  3. Rapid and irregular breathing
  4. Speedy heartbeat
  5. Extreme drowsiness

What happens when you give your dog too much Benadryl?

8. Dodging Doubts

While Benadryl is considered to be one of the safest and most commonly suggested over-the-counter drugs for dogs, there are still a few health conditions that may deem it to be not the best option. Some of these are:

  1. If your dog is suffering from chronic kidney disease.
  2. Record of any lung disease.
  3. In cases of heart disease and other cardiac conditions.
  4. Consistent low blood pressure.
  5. Glaucoma is a type of disease affecting
  6. If your dog is presently pregnant.

9. Things To Be Very Careful About

Avoid using time-release capsules for your dog
Photo by Leohoho on Unsplash
  • Avoid giving your dog time-release capsules. These get absorbed in a dog’s system much differently than they do for humans. Other than this, a dog may end up chewing on the capsule and cause an overdose instead of the gradual release.
  • Only opt for medicines that have the active ingredient diphenhydramine in their composition. Decongestants or alcohol in the composition are toxic for your dog’s system and must never be given.
  • Even if you have read plenty of data regarding the dosage to be given, it is always necessary to first take a trained professional’s advice for the same. While your pet’s weight determines a general dose of how many milligrams must be given, the proper dosage after understanding your dog’s overall condition will best be selected when you consult your veterinarian.

10. Alternative To Benadryl For Dogs

As mentioned, some dogs may develop further allergies to Benadryl itself. In this case, other medications may help relieve symptoms. These are mainly advised for seasonal allergies only.

Loratadine and Cetirizine are usually considered safe when given in the proper doses. These medications should again be checked for the presence of decongestants.

For milder allergies, including itching, use Cortisone cream or shots, as these are considered faster methods. It is to be noted that Cortisone cream/shots are supposed to be a short-term treatment only.


Dog allergies do require medical attention, depending upon the dog’s symptoms. These can vary from seasonal allergies to food allergies.

Liquid medication of Benadryl, Benadryl treatment, or mildly mixing it with pet food for easier consumption may make it easier for your dog to consume it.

Benadryl is considered to be the go-to allergy medicine, an antihistamine drug for our pets. Although it may act as a mild sedative along with the common side effects, if your dog does not suffer from chronic illnesses, he/she will be able to get through the allergy with the help of Benadryl.

In case of adverse reactions, the first and foremost thing to do is rush to an emergency veterinary hospital.


1. Can I use human Benadryl for my dog?
Yes. Benadryl is an over-the-counter medication that is labeled for humans but is generally considered safe for dogs in the appropriate dosage. Always consult with your veterinarian before giving your dog any medication.
2. Will Benadryl make a dog sleepy?
You may also notice that Benadryl does, in fact, make your dog sleepy. The majority of side effects occur within the first hour of administration, so monitor your dog’s reaction carefully during this time frame. In the event that his reactions are severe, contact your dog’s veterinarian immediately.
3. Does Benadryl stop dogs itching?
And while antihistamines, such as Benadryl®, have historically been an accessible and easy over-the-counter option for relief, studies have demonstrated that they have little to no effect on long-term skin allergies and dog itchiness.
read more
  1. De Martinis, Massimo, et al. “New perspectives in food allergy.” International journal of molecular sciences 21.4 (2020): 1474. ↩︎
  2. Parisi, G. F., et al. “Antihistamines in children and adolescents: A practical update.” Allergologia et Immunopathologia 48.6 (2020): 753-762. ↩︎
  3. Volk, John O., et al. “Executive summary of the Merck animal health veterinarian wellbeing study II.” Journal of the American Veterinary Medical Association 256.11 (2020): 1237-1244. ↩︎
  4. Tan, Siew Mei, et al. “Electrospinning and its potential in fabricating pharmaceutical dosage form.” Journal of Drug Delivery Science and Technology 76 (2022): 103761. ↩︎

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Jahnavi Dass

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