"been using this for 16 months for ongoing knee pain following surgery. works well, with minimal side effects. at this point i only feel slightly different and able to function quite well. only side effect i really get is dependence which can be bad. but it helps with the pain considerably and i can&#039;t seem to get off of it. i&#039;m 76 years old. i&#039;d rather live out my life being able to play with my grand kids and enjoying their company then sitting at home in pain. hope this helps."