Oh, I see where you're coming from. You could be right about that.
I know I wouldn't be a good subject for a study like that because I have atypical reactions to medicine. You know the little 'also reported in .7% of the subjects' part on package inserts? That's me. When I first started having big trouble with pain I only used aspirin - until one day I used so many mg. my ears were ringing so loud I couldn't hear the air conditioning unit in my window; I was afraid of cutting myself and bleeding to death. That's when I started to use Tylenol & aspirin together. It was about 1996. Tylenol helps (somewhat) but it's slow to kick in. Aspirin kicks in fast, but it doesn't last as long. So there you have it.
That sounds like an interesting focus of research to persue; I'd like to hear what protocols you'd use to discover correlations.
I have heard and seen research on pain relievers losing effectiveness for people over time - that people need higher doses to get the same effect - but I hadn't heard of them actually making the pain worse. That's awful! Do you have any links to data where I can check that out? I'd be interested in knowing more about that.
Bioethics - a whole new realm of science for manufacturers to ignore.