The Dr didn't believe me and gave me 2 tylenol suppositories for my fever in the ER because I had had motrin 2 hours before(which does work)-later when my fever whent up instead of down-he said i guess you're right. For some reason twighlight drugs don't work on me either-I remember every second of my colonoscopy and will never have another! I remember hearing something on a radio dr show that it is common for someone who is immune to Tylenol to be immune to twighlight drugs also because of the way they work. I can't find anything about it anymore -Have you heard of this? I'm so scared my Dr won't believe me and try to use a twighlight drug for my wrist surgery.