i am quite confused about my pain meds. my pain mgmt Dr prescribed ms con-tin er and pharmacy filled it with ms con-tin sr. i have noticed a difference in how each medicine works and i am wondering if there is a difference between the two medicines? i have been taking ms con-tin er 60 mg for a very long time and i notice that the ms con-tin sr does not work as effective as the ms con-tin er. i have tried to look up this information myself but i cannot find anything on this topic. can someone please help me?? i know i am not imagining this. the er is round in shape and the color is orange with white insides while the sr is orange with orange on the inside. there is not any protective coating with the sr as there is with the er pill. i know the er stands for extended release but does the sr stand for sustained release?? i have not found any in depth information about my query any where and i am needing some assistance please as my prescriptions are about to exhaust and are due in a few days and i do not want to keep getting the wrong medication if for fact the sr is different from the er pills. i have just noticed this switch and i am hoping that my pharmacy isn't taking and short cuts with my medications. please someone out there please help set my mind at ease. and if it cant be put to ease than at least inform me of the differences in these medicines. i will be anxiously awaiting someone to answer my dilemma.