I have osteoarthritis with chronic pain; I take Naproxen and cocodomol to help. It used to take the edge off but now doesn't really touch the pain. I've heard that cbd oil could help but how do you know what to take or what strength to buy? Can I also take it with the prescribed medication too? I am due bilateral knee replacement and have been in pain for five years. My back is now extremely painful too and I think the 'wonky walking' has caused this!