Is infant Benadryl safe for my 8-week-old puppy's vaccine reaction?

Thanks for using Petco Pet Education Center, formerly Petcoach! While this may be a reaction to the vaccines, I would not recommend that you give her Benadryl without having her physically evaluated by a veterinarian. There are scenarios where administering this medication would be contraindicated. I would highly recommend that you have Phoebe evaluated by a veterinarian for further assessment and treatment. Best of luck!

A vaccine reaction is usually caused by an abnormal reaction of the immune system to the vaccine, these two medications suppress the immune system and by doing that they usually stop these reactions.

Benadryl (diphenhydramine) is often given as a pre-treatment prior to giving treatment for heartworm disease to prevent a reaction, so there aren't any specific counterindications to using it in a dog with heartworm disease. However, if your dog is still itchy 24 hours after getting a vaccine, I would fear a worsening reaction, and I would recommend taking him in for a dose of a stronger medication - a steroid - which will definitively work and stop any reaction, as well as the itchiness. I find that Benadryl (used orally) is rarely very effective at stopping itchiness in dogs.

I believe it might actually be part of the original allergic reaction but as there is suspicion he had a reaction to the Benadryl i wouldn't recommend giving it again. instead i would recommend to monitor him, give it 48 hours, if it is not resolved bring him back to the vet for a steroid shot.

Unfortunately, by law it is illegal for the experts at Petco Pet Education Center, formerly Petcoach to give the dose information for any drug, including OTC drugs, without seeing the animal in person first. That's because doing so requires a veterinary client patient relationship which cannot be achieved via an internet forum. In addition, the experts cannot say for certain if a specific drug is safe for your dog. You need to check with Chewy's vet to see if it's safe to give him, and the vet can give you the dose.

Unfortunately, by law it is illegal for the experts at Petco Pet Education Center, formerly Petcoach to recommend using any human drug, including OTC drugs, without seeing the animal in person first. That's because doing so requires a veterinary client patient relationship which cannot be achieved via an internet forum. In addition, the experts cannot say for certain if a specific drug is safe for your dog. If she is shaking and feels hot, she could have a fever which Benadryl wouldn't treat anyway. I would take her temperature rectally. A dog's normal temperature is 101-102.5F, and if her temperature is above 103F, I would take her into an ER vet or a vet on call immediately. Otherwise, I would monitor her and try to tempt her to eat with some boiled white meat chicken (no bones) and white rice in small amounts several times a day. Should her symptoms continue through until tomorrow, I would have her seen by a vet. If they suddenly become worse or she develops other signs like vomiting and diarrhea, I would have her seen by a vet immediately.

Hello, benadryl will definitely treat an allergic reaction, however, if your dog is also bruising and bleeding then that is not a characteristic of an allergic reaction that could be treated with just benadryl. I would recommend having him evaluated for this bruising and bleeding as benadryl will likely note treat this on its own. Hope this helps and best of luck!!!