If you're worried about possible cross-reactions or side effects, you could try a different approach to the joint problem. Excess weight can be extremely hard on a dog's joints, so the first thing I'd recommend is to cut down on your boy's weight. Moderate exercise can be beneficial, especially low impact exercise. Swimming is very easy on the joints and is a great form of exercise if your dog tolerates water. (Mine don't
) Maybe some of the joint problems will resolve without the use of the supplements.
Also, have you considered a change of diet? I know of a dog that suffered from bladder stones and was switched to raw. His urine acidified on the raw diet and the stones were no longer a problem (I don't know for sure what kind of stones he had, though
). I'm no food guru, but maybe some of our other members who have more experience in nutrition can offer you some suggestions for research.
Good luck with your dog, Brute! And welcome to the forum. When you have a spare moment, we'd love to see pics of your yorkie if you have some to share.