Why is my dog acting so hyper after taking Benadryl for allergies?

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.

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!

The calculation for Benadryl is quite simple, it just 1mg per lb , so for a 5 lb dog it would be around 5mg. Since Benadryl comes in 25mg usually this is close to 1/4 tablet and there is a wide safety margin for Benadryl so 1 or 2 mg above or below is well tolerated. Expect some drowsiness just like in humans.

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!

Thank you for submitting your question regarding Misha. I typically recommend giving Benadryl at 1mg/pound. So I would give around 12mg orally every 8 hours. The dose you were told is a little high, but probably still reasonable. Antihistamines are a somewhat hit and miss in dogs. They will help some dogs, but not others. If you do not see an improvement in the skin around his eyes, then he will need to see his veterinarian. He could have a food allergy, for example, as this commonly affects skin around the eyes. In these case, the dog may be experiencing vomiting, diarrhea or an increased number of bowel movements per day. These dogs can also have skin issues elsewhere and are prone to ear infections. I hope this information helps!

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.

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.