I was on the Fentanyl patch, starting at 25mg and worked up to 100mg. It did help with the pain; however, there was one serious side effect: rather than release the medication into my body over a period of 72 hours, I would get a full three day dose in a matter of 24 hours. Thinking it was the brand of patch, my doctor wrote the script for another brand. Same thing happened. I obviously had to stop the use of Fentanyl all together as it was poisioning me. Has anyone else had this problem?