As someone who's not a drug addict or around people who use substances that might be tainted with it, I don't want this. If I'm in a car accident or a serious condition where I need immensely powerful pain-killers I sure as you know what want Fentanyl to work.
Not really. There are people for whom Fentanyl is the only real choice for use _during_ surgery. I'm one of them, and I don't want doctors mucking about inside my chest without ample pain relief.
Fentanyl (and the derivative the vaccine works on) have very short half-lives, which is ideal for _minimal_ dosing during surgery. Any drug that lengthens the QT interval, or fucks with the S wave will bring about catastrophic heart failure in people with conduction channel issues. The only time alternative anesthetics are given to me for example is to induce heart failure in order to test new leads.
I find the idea of a vaccine that makes therapeutic drugs fail to work quite scary personally.