A great place to start when looking around for some inspiration (or huge gaping gaps).
This article is about social media and digital initiatives by pharmaceutical companies in the year 2012.
There has been a good deal of work to dig around and investigate the higher profile initiatives.
As usual with these articles the authors focus on English language initiatives as they're the easiest to spot and understand. Be aware that there are many more initiatives in different languages, many of them even more avant-gardist and driving real engagement.
BTW I've heard that Dose of Digital is updating its Wiki and will publish shortly - will be worth keeping an eye open (or simply RSS it) :-)