It wouldn't be medication unless there is hip and elbow dysplasia or arthritis actually diagnosed, rather supplements which many vets recommend for the breed as a preventative measure between the age of 5 - 7 years old. If you have an English pedigree, they are statistically more prone to hip dysplasia than elbow dysplasia, though they carry a well-known genetic predisposition to both. Arguably, because they tend to be bulkier than American labs, that can exacerbate the condition. As I'm sure you are aware, it's crucial to control your lab's weight. I've seen so many owners using supplements whilst remaining completely oblivious to the fact that they are overfeeding their dogs. Also, avoid flingers or hurling a ball long distances because when they get up to full pelt and then wheel around it can be very damaging. I know that they do this naturally when they zoomie, but repetitively playing ball games which are anything above short distance and tosses can be very damaging, as can flights of stairs.