Addyi, a drug that made a splash when it was approved in the summer of 2015 as the first “female Viagra,” is back. Its rise, fall, and rise again is an example of shrewd pharmaceutical marketing and the potential dangers it can pose to patients.

Three years ago, a small pharmaceutical company with a big agenda created a fake feminist group so that they could get a bad drug approved by the Food and Drug Administration. The story of how this happened is a case study in how industry affects medical discourse, the subject of a PharmedOut confere...