Benadryl for Dogs

Diphenhydramine for dogs

Benadryl is widely used in the treatment of dogs, but this does not mean that it can be given without the appointment of a veterinarian. In this article we will talk about the use of Benadryl for dogs, dosage, side effects. We also offer you a Benadryl dosage chart from with weight of a dog vs. Benadryl form (pill, liquid, or chewable tablets).

Benadryl, also known by its generic name diphenhydramine, is one of the few over-the-counter drugs that vets routinely have owners administer at home. While it is typically well endured and has a large safety margin, there are a couple of things owners ought to keep in mind before dosing it at home.

Benadryl Usage

Benadryl is an antihistamine, obstructing the H-1 receptors on smooth muscle and blood vessels. A few of its most typical indications are the treatment of environmental allergic reactions, allergies to insect bites or stings, and pre-treatment of vaccine reactions in dogs. It likewise has some effectiveness in the prevention of motion sickness in dogs and as a moderate sedative.

How Does Benadryl Work?

Diphenhydramine is a receptor antagonist, which implies that the drug works by blocking the receptors that get histamines in the dog’s body. This alleviates a lot of the symptoms associated with allergic reactions, like itching, sneezing, and hives. The body still produces histamines, but the receptor villain blocks the receptors from signing up the histamines. It is a bit like the mail-person trying to provide mail to an already complete mail box. The letter arrives, however there is no room for it.


Benadryl is contraindicated with particular conditions, such as dogs with glaucoma, hypertension, and heart disease. It’s constantly best to call your vet for assistance before administering any medication to your pet, including Benadryl.

Benadryl Dosage for Dog

The basic dose for oral Benadryl is 1 mg per pound of dog’s body weight, given 2-3 times a day. The majority of drug store diphenhydramine tablets are 25 mg, which is the size used for a 25 pound dog. Constantly double check the dose before providing an over the counter medication. In addition, many formulas are combined with other medications such as Tylenol so make sure Benadryl tablets contain only diphenhydramine.

Liquid Dosage

If you choose to use liquid for your dog, utilize the children’s liquid formula of Benadryl (preferably the dye-free version), it should not include alcohol or xylitol — make sure to examine the components on package to verify this. At the basic concentration, every 5 mL of liquid contains 12.5 mg of diphenhydramine and can be offered at a dosage of 0.4 mL/lb.

For recommendation, a standard United States teaspoon measurement is 5 mL. You can utilize a syringe to increase the accuracy of the dose and to make things easier when delivering bigger amounts.

Sadly most dogs dislike the taste of liquid Benadryl, so it is better to utilize tablets if possible.


Benadryl recommended dosage according dog weight and form of the medication.
How much should you give Benadryl to dog, depending on the forms of the drug and the dog’s weight.

What Does Benadryl Treat In Dogs?

Benadryl is an over-the-counter antihistamine that relaxes allergies to environmental irritants, insect bites or stings, and particular vaccine responses in dogs. It has actually also been utilized as a sedative and to avoid movement sickness. Though it is a human drug and not FDA authorized for dogs or other animals, it can be given safely with approval from your vet.

Benadryl is the brand name, not the name of the drug that treats allergic reactions. Diphenhydramine is the active drug in Benadryl that is safe for canines when given up the correct dose. There are numerous other brand names that make similar products, and there are other drugs under the Benadryl brand name that you should use caution to avoid. Check out the ingredients of the medication prior to offering it to your dog and ask your vet before giving any medication to your dog.

Benadryl for Allergies

When we consider allergies, we usually think about red and itchy eyes, a runny nose, sneezing, etc.

Dogs have different symptoms when experiencing allergic reactions. For the most part, dogs show allergy symptoms on the skin’s surface area. Although Fido can show signs of allergic reactions that are similar to those of humans, you’ll want to make sure that your pup does not have a more severe condition at hand.

Nasal discharge, coughing, and inflamed eyes can be a sign of a variety of conditions in dogs, including respiratory infections. For that reason, it is vital not to assume that allergic reactions are causing these symptoms automatically.

The bottom line is that your dog can suffer from allergies. Your vet might suggest Benadryl to minimize your dog’s allergy symptoms.

Allergic reactions in dogs consist of:

  • Seasonal allergic reactions
  • Food allergies
  • Environmental allergic reactions
  • Allergies to snake bites
  • Allergic reactions to insect bites

Regrettably, regardless of how we wish it were possible, we aren’t correctly able to interact with our dogs in a clear, concise way. They can’t let us know when something in the air, or their food, is making them feel funny.

We also can’t explain to them how severely ant bites feel and tell them to avoid those fun-looking mounds in the grass.

For this reason, understanding that Benadryl is safe for dogs (to a degree) makes many dog owners feel at ease if their adventurous pup is susceptible to itchy circumstances.

With that stated, we wish to stress that, as in people, allergic reactions and other conditions can be mistaken for one another.

For example, you’ll want to guarantee that your puppy is experiencing allergic reactions and not a skin infection, as Benadryl is not an effective way to deal with a skin problem. Your vet will have the ability to determine whether your dog has an allergy or skin infection.

Benadryl for Hives

Benadryl is likewise understood to treat hives in both dogs and humans effectively. In dogs, the majority of cases of hives are merely due to allergic reactions of one kind or another.

In humans, hives can be a symptom of several underlying medical conditions, so treating it with a medication such as Benadryl will work for the immediate relief, however not as a long-lasting treatment and certainly not as a treatment.

Although pets with hives may look quite miserable, we wish to implore pet owners not to stress if Fido breaks out in hives, as the hives can be treated, normally with no problems.

Benadryl for Anxiety

A significant side effects of diphenhydramine, the active component in Benadryl, is sleepiness. If your puppy has anxiety, your vet may recommend Benadryl to help alleviate symptoms of anxiety and successfully help your nervous puppy calm down.

Benadryl for Motion Sickness

Many pet owners might not know that Benadryl is frequently suggested for dogs who experience movement illness.

Treating With Mast Cell Tumors with Benadryl

Mast cells are leukocyte that contributes to allergic reactions. When a dog has mast cell growths, there is a mast cell degranulation, which causes an enormous histamine release.

If your dog has a mast cell tumor, your vet may recommend Benadryl to alleviate symptoms from the histamine release from the tumor cells.

Benadryl in Heartworm Treatment

Heartworm treatment involves the killing of adult heartworms. The death of the heartworms can activate a significant allergy. If your pup has to undergo heartworm treatment, your vet may advise Benadryl to ease the symptoms connected with the treatment.

When Is Benadryl Bad For Dogs?

In some scenarios, Benadryl can be very harmful to dogs, which is why it is so crucial to consult your vet prior to giving your dog Benadryl. Here are a few circumstances where Benadryl can be harmful for dogs.

  • Medical conditions. Particular conditions, such as glaucoma, heart problem, or hypertension, can be gotten worse by Benadryl.
  • Other medications. Other drugs, even those that are over-the-counter, can trigger an unsafe reaction when combined with Benadryl.
  • Allergy. Paradoxically, some dogs can have an allergy to Benadryl.
  • Side effects. The most typical is sedation, but dogs can likewise experience changes in breathing, heart rate, and urination. Hardly ever, some may vomit or struggle with diarrhea.
  • Different solutions, brands, or items. Check out the active ingredients. Acetaminophen and Pseudophedrine are not safe for dogs, and they are included in some allergy medications. There are lots of Benadryl products, so ask your vet to make sure you are utilizing the proper one.
  • Overdose. An overdose of Benadryl can be deadly. If your dog consumes excessive Benadryl, call the emergency veterinarian or toxin control hotline at (888) 426-4435 right away. Symptoms of overdose include dilated pupils, constipation, rapid heartbeat, behavioral changes, and seizures.
  • Pregnant or nursing. Dogs that are pregnant or nursing should nearly never be given medication without stringent veterinary supervision.

Side Effects

There are side effects related to using Benadryl for dogs that all dog owners should be aware of. Much like people consult their physicians before taking a new medication, you must always contact your veterinarian prior to introducing Benadryl to see if it has any potential drug interactions with your dog’s other medications, or if it could aggravate a pre-existing condition.

If your dog has any of the list below conditions, only use Benadryl after consulting your vet:

  • Angle closure glaucoma
  • Extreme heart failure
  • Prostatic hypertrophy
  • Bladder neck obstruction
  • Seizure conditions
  • High blood pressure
  • Allergic lung disease
  • Pregnancy

Common side effects related to utilizing Benadryl for dogs consist of:

  • Sedation
  • Dry mouth
  • Urinary retention
  • Hypersalivation
  • Increased heart rate
  • Rapid breathing

Unusual side effects:

  • Diarrhea
  • Throwing up
  • Reduced cravings
  • Increased hunger

A lot of side effects happen within the first hour of direct exposure, so monitor your dog thoroughly during this time.


It is possible to overdose on Benadryl for dogs. Signs of an overdose include hyper-excitability of the central nervous system (CNS) and can be deadly. Other indication to watch for are:

  • Rapid heart beat
  • Dilated pupils
  • Agitation
  • Constipation
  • Seizures

If you think your dog has overdosed on Benadryl, call your vet or emergency veterinary health center instantly.

Some dogs establish an allergy to Benadryl. If your dog begins having symptoms of an allergic reaction, look for veterinary care instantly.

As Benadryl for dogs is frequently utilized to treat allergies, keep an eye on your dog after giving Benadryl for the very first time to make sure that the allergy symptoms don’t aggravate.

When Does Veterinarian Should Be Involved?

Oral Benadryl is considered a moderate to reasonably effective antihistamine. If a pet is having an acute allergy with facial swelling or difficulty breathing, avoid the oral medications and go straight to the vet. Lots of allergic diseases need a combination of medications and treatment of underlying infections; if your animal is not reacting to the medication, speak to your vet for other options.

References and used sources

Reyus Mammadli

Having engineering and medical education, in recent years actively engaged in the study of the development, reproduction of domestic animals. Special attention is paid to the treatment and prevention of diseases of Pets.

Author of several hundred articles about health and healthy lifestyle. In recent years, he has been treating Pets and birds together with specialists. In their articles on shares both his knowledge and experience, and, based on reliable sources, methods of primary diagnosis of diseases in Pets and General recommendations for their possible treatment.

Of course, the articles are only informative. In each case, diagnosis and treatment should be carried out and prescribed by a qualified veterinarian.

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Leave a Reply

  1. Geta Martins

    My dog hates eating Benadryl, but in some cases it’s needed since he’s a Boston Terrier and he’ll break out in a rash due to an innate sensitivity that he has.

  2. Dr. Unker

    Every pet person ought to own “The Pill Book Guide to Medication For Your Dog And Cat, Bantam Books. p 198, Benadryl (Diphenhydramine) there are lots of preventative measures and possible side effects such as Common: drowsiness, dry mouth and urine retention. Uncommon decreased hunger, vomiting and diarrhea.


    Dogs: 1-2 mg/lb 3-4 times a day

    Felines: 1-2 mg/lb 2-3 times a day

    Drug kind: Diphenhydramine can be found in a variety of forms for internal and external use. The pediatric elixir or syrup (12.5 mg/ml) might be the most convenient form to administer orally to dogs and felines. It is also available in 25mg and 50mg tablets and capsules and injectable.

  3. Susie Richardson

    It is safe to give most dogs Benadryl however this is something best asked of your veterinarian as your dog may have a condition that may hurt your dog. I have actually offered Benadryl to my Blue Tick Coonhound to try to stop his chewing of his paws (my veterinarian recommended me to try it and provided me dose details), nevertheless a vet likewise told me to give Benadryl to my 20 pound dachshund and it had an awful effect on him. While my larger dog got a little sleepy my small dachshund had the opposite response and he was restless, his heart was pounding quickly and it didn’t assist him at all. I never ever offered my dachshund Benadryl again after the first time due to the bad side effects. Please contact your vet about offering Benadryl to your dog and likewise about the dosing directions.

  4. Natasha Harris

    Benadryl is definitely safe to give to dogs in the appropriate dose, for instance I give my 22 LB dog a single 25 mg dose of Benadryl. Excessive Benadryl will cause seizures. More than likely it will not eliminate your dog however you truly don’t wish to offer to much since seizures are severe. If you have a Brachycephalic dog (pugs, frenchie’s and other short nosed dogs) that gets an allergy that could kill your dog in a brief time which is really when Benadryl is available in very handy. I am not a veterinarian so please call your vet and ask the right dosage for your dog. Then go out and get some since in certain situations Benadryl is a life saver.