It works fine and has for decades as long as you keep in mind what it's purpose is.  Something you have to keep in mind is that the mortality or fortitude of a criminal today isn't any different than it was in the past, no matter how far back in time you go.  Drugs or not, people are still made of flesh, blood, and bone. 

I even argue that the real diehard criminals in the old days were far more brazen and were even much more mentally tough back then than some of these punk thugs are today.  Just think of those public enemies during the ganster era of the early great depression.  They didn't need a fix of PCP, meth anphedamines, or cocain to go against an army of lawmen.  They did it of their own fortitude, bare nerves, and guts, and often came out winning too.  Many of them even carried the .380 ACP as a back-up or conceal weapon.  Ammo today is much better than it was back then.  Hit someones centeral nervous system with anything and they'll be stopped no matter what exotic drug they're on.