To my understanding buprenorphine is used to "detox" patients off of opiate drugs. It is an opiate but is used in small doses to control ill effects of detox...kinda like suboxone and methadone. It is meant to block the effects of other opiates like heroin and such. Morphine I would believe is stronger. But if you take bup. why would you take morph.? Can you explain maybe some more? Are you asking for the "ceiling" because you are taking bup. but you want/need the effects of morphine to work while on bup.? If you are in "pain" then go to the hospital and they can administer the proper does of morphine,if medically necessary, being on the opiate antagonoist.