Hello everyone! I take tevas oxycodone sr 10 mgs. 5 times a day for my chronic pain issues associated with two spine surgeries, the last being a l-5/s-1 anterior-posterior fusion.I have to get more fusions per the doctor but I am only 30 so the doctor told me that I better get used to the pain meds...I am going to have to take them for the rest of my life. So my concern is that I have noticed that some times the releif is up to 6-7 hours per tablet but on other times its only up to 2...What the problem? Is there such thing as a bad or unchecked batches? Please if anyone knows anything regarding this issue please let me know! I hope it is not just my imagination !lol!