The best pain killers for dogs are the ones made for the veterinary market, such as Carprofen (Rimadyl
), Deracoxib (Deramaxx) and Meloxicam (Metacam). These are all in a class of medications called NSAIDs, which is what Aspirin is.
Other medications in this class, such as Ibuprofen, Naproxen (Aleve), etc. can be toxic
at relatively low doses in dogs and are NOT recommended.
Aspirin is sometimes used in dogs at a dose of about 5 mg per pound of body weight, but I generally discourage owners from using it unless they know for certain that they are not going to want to use a different medication later. Aspirin tends to provide mediocre pain relief in dogs with a higher risk of side effects than the other, veterinary-specific NSAIDs. Also, if you have given aspirin, your vet will have to wait several days before switching to a different NSAID, so if aspirin is not enough, you have made things much more difficult.
Veterinarians can also prescribe other classes of pain medications such as tramadol or gabapentin if they are needed for the specific situation, but these are prescription-only.
Edited by Dr. Oz on 11/8/2009 at 1:02 AM EST