I'm not an expert, but I've never heard that the controlled release part of Oxycontin isn't as reliable as MS Contin. I take Oxycontin and Oxycodone for breakthrough pain and it works really well most of the time. Some days my pain level is just too high for good relief. I was on MS Contin before without as much relief. Some doctors are just too afraid to prescribe Oxycontin and maybe that is what your doctors problem is. Good luck to you.