Why do different pain killers have different effects on people?
I've noticed some pain killers working great for me, while others have no effect. I doubt there is much of a placebo effect at work, since most of these either did or did not work when I first took them, without having expectations either way.Why do some pain killers work while others don't?**Is there an underlying mechanism, that explains why some of these work while others don't? Does that predict if pain killers that I haven't used yet will work?