I Accidentally Gave My Dog Too Much Benadryl

If you suspect that your dog may have eaten any Benadryl, or if you think you may have accidentally given too much, contact your veterinarian or an emergency veterinary clinic immediately. You could also consider calling Pet Poison Helpline at 855-764-7661 or ASPCA Animal Poison Control at (888) 426-4435.

What Does Benadryl Treat In Dogs?

I Accidentally Gave My Dog Too Much Benadryl

Benadryl is an over-the-counter antihistamine that calms allergic reactions to environmental allergens, insect bites or stings, and certain vaccine reactions. It has also been used as a sedative and to prevent motion sickness.

Though it is a human drug and not FDA approved 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 allergies. Diphenhydramine is the active drug in the medication that is safe for canines when given in the proper dosage.

There are many other brands that make similar products, and there are other drugs under the Benadryl brand that you must use caution to avoid. Read the ingredients of the medication before giving it to your dog, and ask your vet before giving them any medication.

Causes of Benadryl Poisoning in Dogs

Allergies in dogs are the defensive mechanism of the immune system which employs specialized immune cells in the dog’s body to defend it against a substance that it sees as an invader. The specialized cells the body uses to protect itself are known as mast cells, and when the immune system is stimulated by allergens, the mast cells release histamine into animal’s system, which has an inflammatory effect on any tissues that it contacts. This results in the itchy and inflamed skin conditions characteristic of most allergic reactions in dogs. Benadryl, when acting as a remedy for allergies, like other first generation antihistamines, blocks the receptors that the histamine would attach to, thereby stopping the reaction to the histamine. However rare, an allergic reaction to the Benadryl itself is possible.

Toxicity resulting from a large ingestion of a product like Benadryl is caused by the overconsumption of ingredients in the antihistamine. Safe under normal circumstances, the overdose of products that cause effects like drowsiness, muscle tremors, and agitation can be dangerous for your pet, leading to poisoning.

When not to use Benadryl for Dogs

Certain canine health conditions can make the use of Benadryl very dangerous. Therefore, it’s essential to contact your vet before giving Benadryl to your dog.

Medical conditions which make it dangerous to give your dog Benadryl include pregnancy and nursing, glaucoma, heart conditions, and low blood pressure.


Is 25 mg too much Benadryl for a dog?

Therefore, a simple and practical dose is 1 mg of Benadryl per pound of your dog’s weight, given 2-3 times a day. For example, a 10-pound dog might receive a 10 mg dose in the morning, afternoon, and evening. Most diphenhydramine (Benadryl) tablets are 25 mg, which would be the appropriate size for a 25-pound dog.

Will too much Benadryl hurt my dog?

While it’s uncommon, your dog can experience an overdose of Benadryl which can be fatal. If you see any of the following symptoms or believe that your dog may be experiencing an overdose, contact your veterinarian immediately.

What happens if you give a dog two Benadryl?

If you suspect your dog has overdosed on Benadryl, contact your veterinarian or emergency veterinary hospital immediately. Some dogs develop an allergic reaction to Benadryl. If your dog starts having symptoms of an allergic reaction, seek veterinary care immediately.

Is 50mg of Benadryl too much for a dog?

Official answer. The general dose of Benadryl (diphenhydramine) is 2 to 4 mg/kg up to three times day. If your dog weighs 25 lbs (11.3 kg) the dose of Benadryl would be 22.6mg to 45.2mg up to three times a day. Benadryl tablets are available in 25mg and 50mg strength.