Thursday, November 12, 2009

Headlines Underscore Drug Risks

Recent headlines underscore the risks associated with drugs, including drugs popularly understood to be relatively safe. The stories show not only the inherent risks of drugs, but also the difficulty people have acknowledging those risks.

The first story involves aspirin. A standard-of-care revision in the United Kingdom takes back that country’s previous recommendation of a daily aspirin regimen to prevent cardiovascular disease. Aspirin is not as effective at this as previously thought, creating a negligible decline in deaths. A review panel concluded that for most patients, the benefits are less than the risks, specifically the risk that daily aspirin could cause internal bleeding. That too is an uncommon occurrence, but more common than the benefit an aspirin regimen might provide. Aspirin may still be used in this way in patients who already have cardiovascular disease, especially in patients who have had heart attacks, but doctors need to weigh the risks and benefits in each case.

Acetaminophen, once thought to be safer than aspirin, is also under scrutiny again. Four months ago, the Food and Drug Administration added new restrictions on the popular pain reliever because of its capacity to cause liver damage. Acetaminophen has been shown to cause fatal liver damage on rare occasions even if the drug is used in the intended doses and only for a day or two, but the risks become emphatic when people exceed the recommended amounts — easy to do, as acetaminophen is an additive in thousands of drugs, and that fact is not always clearly disclosed.

A risk of liver damage is bad enough, but now we learn that acetaminophen may trigger asthma. A study at the Vancouver Coastal Health Research Institute reviewed data on 425,000 subjects and found that acetaminophen use increases the risk of developing asthma in the following year by 60 percent in children and 75 percent in adults. There were higher risks with higher amounts of the drug, hinting that the drug may be the cause of many cases of asthma.

A separate study last month found that acetaminophen appeared to reduce the effectiveness of childhood immunizations. It has long been known that drugs can interfere with each other, but this particular combination created an effect that had not been anticipated. It is a concern that is particularly relevant now as acetaminophen may be undermining the ongoing influenza immunization campaign.

Finally, there are the many recent investigations into the deaths of public figures that ultimately concluded that the deaths were simple adverse drug experiences. The prescription drugs involved, it turned out, had been properly prescribed and used in accordance with the prescription, or nearly so. In some of these cases, prosecutors were absolutely convinced that some kind of abuse must have taken place, not wanting to believe that a person could drop dead from a routine prescription drug. All the evidence pointed in that direction, though, and charges against the prescribing physicians could not be pursued. Although there has been a flurry of these cases in recent months, each one seems to involve a different drug, or combination of drugs — telling us that it is not a single drug that is risky, but drugs in general.

None of this, of course, should come as a surprise. People have been cautious about the use of drugs since ancient times, long before there was any science to validate that caution. National authorities limit the availability and packaging of most drugs specifically because of the dangers involved. Most drugs in common use have been only lightly studied, so it is to be expected that scientists would continue to learn new information about their effects.

I don’t believe that we are headed for a future in which drugs become less important, but we may be using drugs more systematically in the future. As we learn more about the circumstances in which drugs can be used to good effect and those in which drugs are better avoided, we will be able to use them more successfully, and not so much in the pattern of trial and error that is the rule today.