There seems to be an emerging consensus not only that Vioxx is a bad drug, but that Merck has known for years about Vioxx’s cardiovascular side effects.

If this were true, why would Merck voluntarily conduct a study that measured Vioxx’s effect on cardiovascular outcomes? Wouldn’t it have been smarter, if Merck knew about Vioxx’s problems all along, simply to sell the drug without conducting any new clinical trials?

This Medpundit post is a good antitode to emerging conventional wisdom. As Medpundit explains, the clinical trial now being touted as proof that Merck knew about Vioxx’s problems compared Vioxx to naproxen rather than placebo. Merck has said all along that it was not clear whether the elevated risk of cardiovascular problems among Vioxx users in that study was attributable to the dangers of Vioxx or to a cardioprotective effect of naproxen. Faced with a flood of lawsuits, Merck will argue (quite reasonably) that the issue was not settled conclusively until new placebo-controlled trial results came in a few weeks ago.

Many thoughtful posts on the Vioxx recall at Derek Lowe’s site and RangelMD. An excerpt from one of Lowe’s posts:

I see that some of the Merck/Vioxx coverage has been along the lines of “Company Finally Heeds Warnings of Unsafe Drug.” Boy, the tort attorneys have to love that sort of thing. It’s true that Merck had some signs that Vioxx could have cardiovascular problems, but there are a lot of drugs, unfortunately, that show rumblings of this sort. Some of them turn out to be false alarms, and some of them turn out to be real. This one turned out to be real with fangs.

If we immediately pulled every drug that showed any indication of trouble, it’s for sure that no patients would come to harm. But we wouldn’t have very many drugs, either. It’s possible that Merck could have moved more aggressively to see if Vioxx had these problems or not – but if companies immediately ran fully-powered studies to address every red light that comes on, we’d have even more enormous costs to make up than we do already. Nothing’s free.