The marketing practices mentioned in the last posting sound a lot like radio-station payola - paying to get a song on the air. There was an interesting defense of this practice mounted recently over at Marginal Revolution (see the first three postings here.
Is there a difference in this case? (I mean, short of the "we're-talking-about-people's-lives-here" argument, which can be valid but ends things before you have a chance to do any potentially useful thinking.) I think there is, and it has to do with market efficiency.
Whether a song becomes a hit or not is based on a relatively quick aesthetic call by a large audience: "I like that." The pro-payola argument (or at least the non-anti-payola one!) is that you can't force a song to be a hit by paying for airplay - all you can do is pay enough to give it a chance to become one. There are historical examples of songs and artists that likely wouldn't have had a chance without someone opening their wallets.
But paying doctors to prescribe certain drugs is a different sort of market perturbation. For one thing, there's not such a good feedback mechanism as there is with listener choice. It takes a while before you can tell if most medications are working or not, days or weeks. And even then, it may not be apparent to the patient. Blood pressure therapies don't make you feel much different at all, even when they're lowering life-threatening hypertension. And most chemotherapy (to pick an extreme case) makes you feel absolutely worse, immediately and continuously, even if it's managing to put your cancer into remission.
And songs are more clearly differentiable, making their market more efficient. Listeners can pick out a new song by an established artist quickly, and if it's someone they've never heard before, they'll notice that, too. But the differences between, say, the different statins are more subtle. You won't feel your HDL increasing a bit more with one of them versus the other - heck, unless they look at a large statistical sample, physicians won't notice that, either. And there's the large question, in this case and others, of whether that real difference is enough to have a real clinical effect. No one's in doubt for very long about whether a song has accomplished what it's trying to do.
In radio payola, you're trying to seed a large market and hope that something will then take off through the free choice of the consumers. But who are the consumers in the prescription drug market? There are areas where direct-to-patient marketing works, in which case it's clear that the patients are regarded as the real consumer. The hope is that they'll storm their doctors offices clamoring for the latest therapy (much to the irritation of the doctors involved, I think!)
But in many other fields, it's the physician that's clearly the consumer and the target of advertising. Schering-Plough appears to have been paying for their interferon to be prescribed for hepatitis patients, among other things, and there's never been much (any?) direct-to-patient advertising there. One physician can write for a large number of patients, so the temptation for well-targeted payola is strong. And wrong.