How to Determine Benadryl Dosage for Dogs

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Although Benadryl is primary used to counteract allergy symptoms in humans, the medication (or a generic version) can safely be given to dogs as well. Benadryl contains the drug diphenhydramine, which works as a mild sedative for dogs, and can also reduce symptoms and discomfort from allergies, bug bites, and bee stings. First consult a veterinarian before administering Benadryl to a dog, and keep in mind that you should not give this medication to young puppies or dogs with medical conditions. It’s generally unsafe to administer human medications to animals, including dogs. Benadryl is an exception to this rule. Do not give your dog other medicines that are designed and sold for humans.[1]

Method 1
Method 1 of 3:

Dosing a Dog Correctly

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  1. How.com.vn English: Step 1 Find how many milligrams are in a pill of Benadryl.
    Different stores will sell Benadryl at different concentrations. Read the label to determine how many milligrams of diphenhydramine a single pill of Benadryl contains. It’s common for Benadryl tablets to contain 25 mg, but some may contain a higher or lower amount.[2]
    • If you need to obtain Benadryl, it should be available at any drug store, pharmacy, or supermarket. Benadryl is sold over the counter, so you won’t need a prescription (for yourself or your dog.)
    • Make sure that you check the ingredients and purchase the version that ONLY contains diphenhydramine in it. Other formulations will include other ingredients that may harm your dog.
  2. How.com.vn English: Step 2 Administer 1 milligram per pound of body weight.
    This is the general rule of thumb when giving Benadryl to a dog. Since dogs can be many different weights, you need to know your dog’s weight before administering the medication. For example, if you have a dog weighing 40 pounds, administer 40 mg of Benadryl.[3]
    • Make sure to consult with your veterinarian before calculating the dose your dog needs.
    • You’ll likely need to break Benadryl tablets apart and estimate how many milligrams are in each.
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  3. How.com.vn English: Step 3 Administer Benadryl two to three times a day.
    To successfully counteract your dog’s allergy symptoms, you can give the dog Benadryl every 8 to 12 hours.[4] Monitor your dog once you’ve administered Benadryl the first or second time: if its symptoms vanish, you don’t need to give a subsequent dose.
    • All of the doses should be the same size. Do not give your dog different level dosages of Benadryl throughout the day.
  4. How.com.vn English: Step 4 Give the dog Benadryl before it’s exposed to an allergen.
    Like most antihistamines, Benadryl works most successfully as a preventative drug. If you know that your dog is allergic to something (e.g. a specific type of grass), give the Benadryl before exposing your dog to the allergen. This will prevent your dog from experiencing allergy symptoms.[5]
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Method 2
Method 2 of 3:

Stopping Allergy and Anxiety Symptoms

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  1. How.com.vn English: Step 1 Administer Benadryl for mild anxiety.
    Benadryl can work in both humans and dogs as a mild sedative, which can calm dogs and alleviate the symptoms of anxiety. This can be helpful when taking anxious dogs on car rides, to the vet’s office, or in any other situation where dogs need to relax or sleep. Benadryl can also cut back on feelings of motion sickness in dogs.[6]
    • Do not use Benadryl for this purpose on a daily basis. If your dog frequently seems anxious or uncomfortable, take the dog to your vet and explain the recurring symptoms.
  2. How.com.vn English: Step 2 Counter general allergy symptoms.
    Benadryl effectively works to counter most general allergy symptoms that dogs experience. (Of course, if you know that your dog reacts badly to specific allergens, keep the allergen away from the dog.) Administer Benadryl to sooth symptoms in your dog including:[7]
    • Itchiness or hives.
    • Swelling or inflammation from allergies.
    • Runny nose and eyes.
    • Allergy induced coughing or sneezing.
  3. How.com.vn English: Step 3 Do not administer Benadryl for an acute allergic reaction.
    While Benadryl successfully prevents mild to moderate allergic reactions, Benadryl will not be an adequate treatment if your dog experiences more serious symptoms. If your dog is experiencing difficulty breathing or has facial swelling, take the animal directly to a vet’s office.[8]
    • Veterinarians will have stronger medications at their disposal, and will be able to effectively treat a dog’s severe allergy symptoms.
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Method 3
Method 3 of 3:

Keeping Your Dog Safe

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  1. How.com.vn English: Step 1 Consult a veterinarian before administering Benadryl.
    Although Benadryl is a safe drug to give to dogs, it’s still best to consult your vet before administering the drug.[9] Your veterinarian will have interacted with your dog before, and may be able to provide specifically tailored dosage advice.
  2. How.com.vn English: Step 2 Read the label of the medication.
    Diphenhydramine is the active ingredient in most types of Benadryl in the United States, and can safely be given to dogs. However, if you’re outside of the US, Benadryl may contain other drugs which cannot be given to dogs.[10] Read the medication label to confirm that you’re giving your dog diphenhydramine.
    • For example, some Benadryl products will contain the drug acrivastine as their active ingredient. This drug is not safe for dogs to ingest, and should not be administered.
  3. How.com.vn English: Step 3 Do not administer Benadryl if your dog has a pre-existing condition.
    There are a number of medical conditions which can be worsened by diphenhydramine. The most frequently occurring condition is high blood pressure. [11]
    • Also do not give your dog Benadryl if it has glaucoma, hyperthyroidism, or an enlarged prostate.
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      Tips

      • For most breeds of dog, there is a fairly wide safety margin when administering Benadryl. This means that your dog shouldn’t experience adverse side effects if you give it a little too much Benadryl.[12]
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      Warnings

      • Remember that is it generally unsafe to give human medications to animals, including dogs. Benadryl is an exception. However, do not give your dog any other medicines that are designed and sold for humans.[13]
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      About This Article

      How.com.vn English: Melissa Nelson, DVM, PhD
      Co-authored by:
      Veterinarian
      This article was co-authored by Melissa Nelson, DVM, PhD. Dr. Nelson is a Veterinarian who specializes in Companion and Large Animal Medicine in Minnesota, where she has over 18 years of experience as a veterinarian in a rural clinic. She received her Doctor of Veterinary Medicine from the University of Minnesota in 1998. This article has been viewed 48,687 times.
      41 votes - 90%
      Co-authors: 4
      Updated: November 9, 2023
      Views: 48,687
      Categories: Dog Medication

      Medical Disclaimer

      The content of this article is not intended to be a substitute for professional medical advice, examination, diagnosis, or treatment. You should always contact your doctor or other qualified healthcare professional before starting, changing, or stopping any kind of health treatment.

      Article SummaryX

      If you need to give Benadryl to your dog, give it 1 milligram per pound it weighs. For example, if your dog weighs 20 pounds, you'd want to give it 20 milligrams of Benadryl. If you're not sure how many milligrams are in a pill of Benadryl, check the packaging, since it can vary depending on where you bought it. Generally, you can give your dog Benadryl every 8 to 12 hours until its symptoms subside, but you should always check with your vet first to make sure it's safe for your dog. For advice from our Veterinary co-author, like how to keep your dog safe when you give it Benadryl, scroll down!

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      Thanks to all authors for creating a page that has been read 48,687 times.

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