After a really bad car crash, not my fault, it was the other persons, I have been on lots of opoids from my doctors. My educated guess is that 1) you will "feel" warm amd fuzzy at 1st 2) you will start to get sleepy 3) you will fall asleep. 4) then respiratory depression will start in. 5) finally you will stop breathing. NOt the way that I would want to ctb. Becasue if found and given narcan, waking up from it can be nasty. ALSO, forgot to mention, if you have fantanyl in pill form, one has to be careful NOT to have it in the open and have it start to having flakes or small pieces come off the pills and one breaths it in, fentanyl is powerful enough to make a person potentially od just from that. Be careful with the fentanyl.