Arthritis
We use glucosamine/chondroitin and MSM. MSM is something also given to horses. You can get in in pill form and my doctor says it is not toxic. People with arthritis can take up to 9,000 mg per day. We only give our guys 1 pill per day of each. It really helped our 13 year old female and our 12 year old male. You would have never known they had any problems. I highly recommend it. Also, our vet recommends vitimin C every day to help prevent cancer.
Both MSM and Glucosamine/Chondroitin can be found at Sam's Club, Wal-Mart and most pharmacies. We have found that Sam's club is less expensive.
Good luck. Asperin may help, but it can be hard on their tummys. Our vet told us to give a tagamet (ulcer med) along with the aspirin.
You should ask your vet if he agrees.