Chances are you didn't, and neither did your doctor. Much of what the Food and Drug Administration knows about a drug's safety and effectiveness is not included on the label, say two drug safety experts who are calling on the agency to make that information more accessible.
In this week's issue of the New England Journal of Medicine, researchers from Dartmouth College argue that drug labels don't reflect the nuanced decisions the FDA makes when deciding to approve a drug. The editorial from Drs. Lisa Schwartz and Steven Woloshin recommends easy-to-read fact boxes to help patients weigh the benefits and risks of medications.
If drug labels sometimes exaggerate benefits and play down drug risks, the authors say there's a very good reason: they are written by drugmakers.
While FDA must approve the final labeling, the actual language is drafted by the manufacturer, with input from FDA scientists.
The labeling is based on results from company studies, which generally compare results for patients taking the drug versus those taking placebo.
If FDA decides the drug's ability to treat or prevent a disease outweighs its side effects, the agency is obligated to approve it. But Schwartz and Woloshin point out that benefits may be slim and potential harms may not be fully understood.
"The take home point is that just because a drug is approved doesn't mean it works very well," said Schwartz, in an interview with the Associated Press. "You really need to know more to see whether it's worth the cost."
Schwartz and Woloshin say FDA labeling frequently fails to provide a full picture of a drug's effects.
In the case of Sepracor Inc.'s blockbuster sleeping pill Lunesta, it's virtually impossible to tell how well the drug works based on the labeling, which only indicates that it worked better than placebo, or a dummy pill.
Only by wading through the FDA's 403-page internal review of Lunesta do the details emerge: patients fell asleep 15 minutes faster and slept 37 minutes longer, on average.
"Lunesta patients still met criteria for insomnia and reported no clinically meaningful improvement in next-day alertness," the authors state.
Despite that lackluster finding, the drug has grown into a $600 million-a-year drug for Sepracor, helped by the company's advertisements featuring a green Lunesta moth.
FDA review documents can also hide critical safety information.
The authors point to the example of Novartis' Zometa, which was approved in 2001 to prevent skeletal fractures in cancer patients with brittle bones. The drug was approved in both 4-mg and 8-mg doses, despite FDA findings of increased kidney damage and death with the higher dose.
FDA went back and added language about kidney toxicity in 2008, but the information about death rates is still missing from the label.
While FDA reviews are posted online, they are often hundreds of pages long and written in extremely dense medical language.
Woloshin and Schwartz recommend FDA provide reader-friendly summaries of its drug reviews, to supplement industry-drafted drug labeling.
Earlier this year, the FDA's panel of communication experts recommended the agency adopt fact boxes for all announcements about drug risks and benefits. Woloshin and Schwartz said they have met with FDA leadership to discuss the proposal.
A spokeswoman for the FDA declined to comment Wednesday afternoon.
In a study comparing comprehension of drug benefits, patients showed significantly better understanding with fact boxes versus traditional drug advertising. Seventy percent of patients viewing the boxes correctly identified a superior heart burn medication, versus just 8 percent who viewed drug advertisements, according to the 2006 study by Schwartz and Woloshin.