Read this extensive post at Naked Capitalism entitled "'The Drugs Don't Work': How the Medical-Industrial Complex Systematically Suppresses Negativess Studies." Here's a very brief excerpt:
[Although] the overt corruption of science at work in the drug arena … comes to light from time to time, often in the
context of litigation, the lay public is largely ignorant of how
systematic and pervasive the efforts are to undermine good research
practice in order to foist more, expensive, and sometimes dangerous
drugs onto patients.