All have to remember, all drugs act different. Just because one didn't work for U may work for someone else. Fentanyl worked great for me, morphine was hell. Some are allergic to drugs and don't know it until they are tried. So, all is best to say talked to your Dr. a lot. As soon as you feel bad with any drug, tell Dr. right away. There are many to use and mixed to find the right formula for U. Never give up on pump, Once U take out, U can't put in.