The way it generally works is that Big Pharma releases a new "2.0" version (often a cis-isomer or the same molecule with a non-functional dangly bit on it), then hands out a bunch of money to get a portion of doctors to quit prescribing the old one, and floods the market with advertising about how amazing the new one is, without letting anyone in on the fact that it's actually functionally identical (or, as Cushman points out, sometimes marginally less effective).