I know that the MS Contin the MS Stands for ''Morphine Sulfate" I usually get 100mg of MS Contin they are round grey pills imprinted M on 1 side, 100 on the other. Then this month my DR gives me Morphine Sulfate 100 mg Blue oblong imprinted e365. They are the same strength technically, but the Long blue one's do not work the same. There has to be a difference, I would appreciate anyone's input.