I want to know the difference between oxycodone ER and morphine sulfate ER. I was taking oxycodone ER 80mg tablets, 5 times a day and I had to pay for them. My doctor now wants to prescribe me morphine sulfate 100mg 2 tablets, 3 times in a day. Will it take care of my pain issues like oxycodone did. Please give your valuable inputs. Oxy is so helpful in relieving my pain, but my doctor says its time to make the switch atleast temporarily.