What about twilight anesthesia? With my cardiac problem, I can't have general anesthetics, but I can have Fentanyl/Midazolam to sedate and numb up a bit. Saying "it's specific to fentanyl" doesn't help those for whom fentanyl is a life saving drug.
The reply above that the real issue is WHY Americans like fentanyl so much is on the money in my opinion.