Fentanyl is what the Russian police resorted to when Chechen Mooselimb terrorists took over a theater in Moscow in 2002.
It worked fine. Put the terrorists and the theater-goers to sleep. Russian police then shot the sleeping terrorists.
But, unfortunately, not all the theater-goers woke up.
Somebody on here wrote - “Keith Richards quit using heroin because he could obtain pure heroin any longer”
Which explains (at least to me it does) why Keith Richards hasn’t expired yet.