Some of them, yes. Glucosamine, chondroitin and MSM found with the "people" meds are fine for dogs. Just make sure to check with your vet on dosages. There are also senior dog foods that contain varying amounts of these ingredients you may want to try as well. You could also check with Dr. Cheng on the Pet Health board here at Med Help for dosages. Does your dog have osteoarthritis or something more serious like hip dysplasia?
I am going to try and get her to the vet for a follow up for something else and just talk to him about it. She has slipping knee caps which have gotton alot worse over time. I was told that the surgery is VERY painful for this and usually not worth it. My girlfriend mentioned she was taking the joint meds for her knees and actually noticed a difference so i thought i'd give it a try.