7. Phenylpropanolamine
Phenylpropanolamine, or PPA, was a psychoactive drug that saw many uses over its 60-year history on the market. What is unique about this one is the fact that the FDA never formally approved it.
For six decades, it was used for everything from cold medication to the treatment of psychological disorders to dieting, having a kind of status where it was neither banned nor entirely endorsed.
That is, until researchers from Yale University in 2000 discovered its connection with stroke and cardiac events, particularly in women. The FDA estimates that up to 500 strokes per year would have been prevented if the drug was replaced with something that presented fewer risks.
