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The Precautionary Principle in Action:
Is taking or not taking Vytorin 'precautionary'?
19 Feb 2008 in Regulatory Science, Regulatory Policy
A recent study raised doubt about the benefits of Vytorin, a patented combination of two anti-cholesterol drugs, ezetimibe and simvastatin. Some cardiologists say the study is sufficient evidence to stop prescribing it as widely; others disagree.
The decision whether to take Vytorin or its component drugs rests with patients, but they rely heavily on the advice of their doctors? How can patients makes sense of this debate?
An article in today's Washington Post by staff writer Rob Stein summarizes a debate about Vytorin and other new drugs including Avandia, a drug for Type 2 diabetes. On one side are the advocates of the drugs, including (unsurprisingly) the manufacturers (Merck and Schering-Plough Pharmaceuticals for Vytorin; GlaxoSmithKiline for Avandia), but also many cardiologists and endocrinologists. On the other side are doctors who say that these drugs should not be prescribed nearly as often, if at all.
How does a patient who is not a medical doctor or scientist sort out these competing recommendations?
First, Stein's article makes indirectly clear that the doctors on each side are, in fact, making recommendations. They are not simply providing objective scientific information and encouraging patients to make their own decisions based on their own preferences for precaution. Rather, they are trying to tell patients how much precaution they ought to take, and they are basing these recommendations on their own values, not the values of patients. (They are also trying to influence the federal Food and Drug Administration, which has statutory authority to substitute the agency's preferences for precaution for the preferences of patients themselves. We leave that issue for another day.)
Second, there is no reason why patients should assume that any of these doctors' preferences are at all similar to their own. An example from Stein's article is revealing. He cites Vytorin critic John Abramson:
In short, Abramson and Hadler have strong preferences about how patients should manage their health risks. These preferences are undoubtedly in tune with the preferences of many patients, but they are sure to be highly inconsistent with the preferences of many others.
Abramson and Hadler are both activist opponents of pharmaceuticals, and Abramson opposed drugs like Vytorin long before the recent study came out. The Publisher's Weekly promotion of his 2004 book -- Overdosed America : The Broken Promise of American Medicine -- shows that he has disliked anti-cholesterol drugs for a long time:
A promotional review of Hadler's 2004 book -- The Last Well Person: How to Stay Well Despite the Health-care System -- says "Hadler has an extremely high threshold by which to call something beneficial (for a hard outcome such as death, his preferred cutoff is an absolute-risk reduction of at least 5 percent." Under Hadler's definition, many effective drugs would not be allowed in the marketplace. Others might prefer a weaker test of effectiveness, or perhaps a test that accounts for the severity of the risk. Indeed, one can easily imagine a more demanding definition of effectiveness for drugs that treat minor ailments. Reducing the risk of toenail fungus 5% is much different than increasing by 5% the survivability of pancreatic cancer. In any case, these choices are value judgments, and they cannot be resolved by science or medicine. Does it make sense to vest medical doctors with the authority to make value judgments for their patients?
The choice whether to take anti-cholesterol drugs like Vytorin (and anti-diabetes drugs like Avandia) requires a sometimes complex risk-benefit trade-off. Risks include potential side-effects, some of which could be very serious, and very real financial costs: money spent on pharmaceuticals cannot be spent on other risk-reducing goods, services and activities. Benefits are never certain, but are described in terms of reduced probabilities of adverse events from cardiovascular disease or diabetes. Despite the best efforts of many advocates on both sides to try to simplify the choice, both risk and benefits will always be uncertain.
Faced with uncertainties on both sides, it is not at all clear which decision constitutes the "precautionary" choice. Choosing to take Vytorin or Avandia shows a preference for precaution about the risks these drugs are intended to reduce. Choosing not to take them shows a preference for precaution about their financial costs and potential side effects.
