My vet says Benedryl is extremely safe for dogs, and you can overdose by quite a lot before you're pushing it. You can double the dose very safely, from 1mg to 2 mg per pound of body weight.

There is 12.5mg of the active ingredient diphenhydramine per 5ml/cc. You want the straight stuff, no additives. Liquid will be absorbed faster than a tablet.

Get a bottle of the liquid (elixir) and reserve it for the dog, figure out the dose, and write it on the label with a Sharpie. Tape an appropriately sized syringe to the bottle. If your dog is having a serious reaction to an insect sting (breathing problems), you don't want to have to stop and figure it at the time.

You can use it for insect stings (it's NOT effective for any kind of snake bite), airborne allergies like hay fever, and motion sickness in dogs (dogs only for this last), and allergic reactions to vaccinations. It tends to make the dog drowsy (sometimes it's useful just for calming, such as for thunderstorms) and that might last for quite a while, so don't put the dog in a dangerous situation where it could fall off an elevated deck or into water, etc. Keep the pet confined and keep a close eye on it.

Anaphylaxis is a life-threatening allergic reaction and tends to start immediately. Give the elixir immediately, as soon as you notice a problem, or the dog/cat will be fighting for breath so much that they won't swallow it (drooling can indicate they are fighting for air). Empty the contents of the syringe into the pocket formed by the animal's cheek and keep his muzzle just slightly elevated so he will swallow it instead of drooling it out; don't panic and squirt it directly into the back of the dog's throat and get him to choking, and don't hold his muzzle pointing up.

My vet said for just a local reaction (swollen muzzle, etc), give the 1mg/pound of body weight amount. If dog is having trouble breathing, immediately give the double dose. You may also want to put the dog in the car and get started for the vet. Sometimes the Benedryl alone isn't enough, and they have to use cortisone injections to reduce the swelling in the breathing passages.

If your dog has prostate problems, hyperthyroidism or glaucoma, your vet may not want you to use Benedryl. Talk to him/her before you have a problem, and find out what is safe to use.

Sue