My dog ate too much Benadryl. Is an overdose harmful? What to do?

Oh no! So this dose is over twice the recommended dose for a dog her weight. Unfortunately, the lethal dose for oral diphenhydramine (Benadryl) in dogs has not been studied, but it's believed the minimum needed could be as few as four tablets according to a study published in 2014 in the Canadian Veterinary Journal. It would be best for you to take your dog into the vet now to have vomiting induced. While it is only two tablets, because the lethal dose hasn't been determined, it's better to be safe than sorry. I would find a vet on call to see her now, or take her into an ER vet.

Well that's not good! Overdose is uncommon but it can produce excitement, seizures, lethargy, comas, and respiratory depression. More than likely, Zoey will be more sedate than usual, but if you see any of those signs I mentioned above, take her into a vet immediately. Best of luck.

This is about twice as much benadryl as I would give a dog for allergies or a reaction but this is not a toxic drug and Sadie should be just fine. She may be very sleepy with this dose, however. As long as she doesn't start vomiting or having uncontrollable diarrhea, and seems like her normal self (aside from being drowsy), she should be ok and no need to panic. Hope that helps!

I am assuming you have a 20 mg or a 25 mg Benadryl tablet that you cut in half. So if anything Jon Snow would have received possibly 2-3 mg more than he should have. This is a relatively small overdose and I don't suspect it will cause him any problems but you should monitor him for lethargy/sedation, inappetance, vomiting and diarrhea. If he becomes extremely lethargic or shows any Gastrointestinal side effects he should be seen by a veterinarian as he may need supportive care. If you think he received more than a few milligrams over his appropriate dose of 10 mg then he should be seen by a veterinarian right away just to be safe. Thanks for using Petco Pet Education Center, formerly Petcoach and I hope Jon Snow does not have any ill effects!

While it is not good to overdose on Benadryl, your dog will likely not have any ill effects from a 25mg tablet. Pete will likely have a good night´s sleep. Should he show abnormal behavior or seizures, he needs to be seen by a veterinarian or at a Prt ER for supportive care.

Benadryl (diphenhydramine) has a published range of 1-2 mg/lb, so Bunny should be fine other than a bit of lethargy/sleepiness. A one time dose should not cause any lasting harmful effects. It is always recommended to consult your veterinarian before medicating your pet, especially a young dog.

Her behavior could be from the Benadryl but I doubt it as you gave an extremely low dose of it (I'm assuming you gave 1 tablet at 25mg - not 0.25mg). Benadryl is metabolized very quickly by dogs so they need a very high dose. The dose is 1mg per pound of body weight so she would have needed around 65 mg (so you would have to give 2 or 3 of the 25mg tablets for it to help much). You can refer to this information sheet about using Benadryl in dogs. ( https://www.petplace.com/article/drug-library/drug-library/library/diphenhydramine-benadryl-for-dogs-and-cats/ ) If you are worried about her behavior you should take her to the vet for an exam.