Interesting, I know many people here take Tramadol. I tried it a couple of years ago and unfortunately didn't help me much. BUT... we took our little 20 lb dog to the vet, she has some arthritis and obviously pain in her bag legs. The vet prescribed Tramadol! Said it was very effective for dogs. I said, I think my Mom has some left over can we use that. (sort of jokingly) and she said, sure but then your Mom's dr. will wonder why she's going through it - I said, "yeah, the ol' dog ate it, probably wouldn't fly" Anyway, she is rx'ed 25 mgs twice a day. That seemed like a lot since adults take 50 mgs. We have noticed that her legs are more flexible and she's not as stiff. Her little legs were always just trembling. That has calmed some. Thought that was interesting. She was also rx's a low dose anti-inflammatory. She said the Tramadol is much safer for her as the other can effect her liver enzymes. So - if you have a dog in pain - ask your VET about this! Just wanted to share!