Canine Benadryl

Jack Russell terrier itching ear in grass

Benadryl is frequently prescribed for dogs. It is safe to give to most dogs, but it is crucial to understand what Benadryl is, how much to give your dog, and when to give it to your dog.

What Is Benadryl?

Benadryl is the brand name for diphenhydramine, a medication. Benadryl is an antihistamine that is available without a prescription. It's available in a variety of strengths and milligrams as pills, capsules, and liquid gels. Because it's occasionally blended with other drugs, double-check the label to be sure diphenhydramine is the only ingredient in the product you're buying for your dog.

How Does Benadryl Work?

Benadryl acts as an antihistamine by preventing the body from producing histamine and acetylcholine in response to an allergic reaction. Benadryl relieves watery eyes and runny noses, as well as puffiness, sneezing, itching, and other allergy symptoms. It's also commonly used to put a dog to sleep or alleviate motion sickness.

What to Treat With Benadryl

Benadryl is frequently given to dogs that have allergies or who are traveling. Benadryl can be used in the following situations:

  • When a dog is .
  • When a dog is bit by a venomous reptile or insect.
  • When a dog is itching or scratching from environmental or food allergies.
  • When a dog is travelling and may experience motion sickness.
  • When a dog is in need of something to make it a little sleepy so that it doesn't get impatient, bored, or bark when it needs to be calm and quiet.
  • When pre-treatment of an antihistamine is needed prior to a vaccination that is known to cause an allergic reaction in that dog.

If you have a dog, have Benadryl on hand even if you don't intend on traveling with it or if it doesn't have any allergies. You never know when your dog will be bitten by a spider or stung by a bee while you're at home, and you'll need to give it Benadryl to avoid or decrease an allergic response.

Some dogs are unable to breathe without antihistamines and prompt veterinarian assistance after being bitten by insects or poisonous reptiles. If you can administer Benadryl to a dog that has been bitten by a snake or stung by a bug at home, you will boost its chances of arriving to the veterinarian alive and well. This is especially true for breeds like English Bulldogs and Pugs, which already have impaired airways without the further constriction caused by an allergic reaction.

What Not to Use Benadryl For

Benadryl may help with allergic reactions, motion sickness, and sleepiness, but that doesn't mean it is always appropriate to use. Some reasons why you may not want to use Benadryl include:

  • If you have a highly stressed or anxious dog and want to make it sleepy. Its anxiety and stress need to be addressed and treated instead of just sedating it with Benadryl.
  • If your dog has heart disease.
  • If your dog has high blood pressure.
  • If your dog has glaucoma.
  • If your dog is taking specific medications, you should discuss the safety of Benadryl with your veterinarian prior to administering it.
  • As a sole remedy after a venomous bite. Your dog needs immediate veterinary attention.

For your dog's health, your veterinarian is the finest source of advice and information. If you're thinking of giving your dog Benadryl, see your veterinarian first to be sure you're not doing more damage than good.

Benadryl Dosage for Dogs

Dogs are usually given 1 mg of Benadryl per pound of body weight twice or three times each day. This implies that a 25-pound dog may take one 25-milligram Benadryl pill up to three times each day, depending on your veterinarian's advice. Children's Benadryl liquid may be easier to administer for smaller pets.

Potential Side Effects and Risks of Benadryl

Benadryl might make your dog lethargic, cause dry mouth or urine retention, and cause gastrointestinal problems including diarrhea and vomiting.

Benadryl Overdose

Benadryl has a long history of being safe, but like everything, too much can be harmful. If your pet is given too much Benadryl, it may become drowsy or hyperactive. If a big enough dose is given, it can cause dry mouth, respiratory depression, convulsions, coma, and even death.


"Diphenhydramine. VCA Hospitals.", "Emergencies in Dogs. VCA Hospitals.", "Buchweitz, John P et al. Fatal diphenhydramine poisoning in a dogThe Canadian veterinary journal = La revue veterinaire canadienne vol. 55,11 (2014): 1089-92." ;