Why do different pain killers have different effects on people?

Question

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?

Answer 1

Biologic variation is a common phenomenon. There are several possible reasons why certain drugs work and other do not for a particular individual. In your case, you didn't mention the type of pain killer, i.e. the class nor did you mention the type of pain. Not all pain killers work for all types of pain. Also, some pain killers rely on the original drug to be metabolized before they work, and different people have different levels of enzymes that metabolize the drug. If you are a "low metabolizer", those drugs are less likely to work for you. Of course, this is a fairly vast subject, so the above is only a brief discussion of the issue.