The FDA just announced new regulations for pharma and biotech companies that wish to promote their drugs via Twitter (Nasdaq: TWTR). Companies cannot brag about a drugs benefits without also tweeting about the associated risks of taking it. There aren't a lot of companies currently promoting in 140 characters, but given clear guidlines we could see an increase in sponsored tweets.

In this episode of Market Check-Up, the Motley Fool's health care focused investing show, analysts David Williamson and Michael Douglass, discuss the new FDA regs, why stocks like Ariad (Nasdaq: ARIA) and VIVUS (Nasdaq: VVUS) will have trouble in this new medium, and the most likely to use this new marketing avenue. Watch and find out.