I previously mentioned Kalman Applbaum's excellent post on conflicts of interest, and he has since produced a wonderful series of posts on pharmaceutical marketing, capitalism, and medicine.
Excerpting them will not be helpful, IMO, as they should be read in their entirety.
The series consists of three posts: here, here, and here.
As someone with a pronounced interest in matters related to conflicts of interest, I have found over the past few years social science approaches to be especially useful in framing some of the inquiries and illuminating key pieces of data. For example, the primary evidence suggesting that even small gifts are troubling from an ethical perspective stems from the extensive social science literature on the effect of gifts in producing social cohesion. Gifting accomplishes this by promoting reciprocity among the gifter and the giftee, which is, of course, exactly the point of doing so in the relationships between prescribers and pharmaceutical/medical device companies.
Analyses of this quality usually languish behind a paywall at a publisher, so take advantage, and go read Applbaum.
