Drug Reactions on the Rise

If you’ve ever gotten a rash from taking an antibiotic or gained weight on an antidepressant, you know that taking medicine means balancing the benefit of the drug against the possible risk of unpleasant, and sometimes even dangerous, side effects. The U.S. Food and Drug Administration (FDA) calls these unwanted consequences “adverse events,” and once a drug is on the market, watches closely to see if it needs to reevaluate a drug’s safety. FDA does this in part through their MedWatch program, where health professionals and the general public can report any reactions or problems they suspect may have been caused by a medication. Medwatch reports and those submitted by drug manufacturers are combined into a single database for drug safety evaluation, the Adverse Event Reporting System (AERS).

According to a study recently published in the Archives of Internal Medicine, the reporting of serious adverse events through AERS (those that can lead to hospitalization, significant health problems, or even death) has increased dramatically in recent years — a 2.6-fold increase in serious events and a 2.7-fold increase in deaths reported between 1998 and 2005 (the last year for which data was available for the study).

In fact, half of the 2.2 million total reports in the database since its inception in 1969 were received in just the past 10 years, the study found, increasing at a rate of more than 11 percent per year. Slightly more women than men had adverse events (55 percent compared to 45 percent).

Does This Mean Our Medicines Have Become More Dangerous?

Not necessarily, says the study’s lead author, Sheila Weiss Smith, PhD, director of the Center for Drug Safety at the University of Maryland. The spike could be due to several factors:

  • Greater awareness of the reporting system
  • Access to the Internet, making it easier for people to report problems than the old system (in which you had to call, fax, or mail a report to FDA)
  • The fact that people are taking more drugs for longer periods of time (thus increasing the potential for side effects, as well as interactions between drugs)
  • The aging of the U.S. population (older people often experience more problems with drugs)

News reports of FDA action on a drug also tend to increase the number of reports, says Dr. Weiss Smith. Her research found that many reports about problems with the anti-inflammatory drug Vioxx came in after it was withdrawn from the market.

On the other hand, some newer drugs also have more inherent risks and side effects. Among the most frequently reported drugs in the study were several recombinant DNA drugs used to treat autoimmune diseases like rheumatoid arthritis. Because such drugs, such as Humira or Enbrel, are used for serious illnesses for which few other effective treatments are available, patients need to discuss with their doctors whether the benefits of treatment outweigh the risks (more on this below).

What Is the Adverse Event Reporting System?

The reporting system is designed as a safety net to flag potential drug problems, explains Robert Feroli, Pharm.D, medical safety officer at the Johns Hopkins Medical Center Department of Pharmacy. FDA has to perform a balancing act between getting drugs to the market quickly and learning as much as possible about potential adverse effects. Because drugs are tested on a relatively small number of people, only after a drug is released can you get a full picture of potential problems, based on a large, diverse population. For example, Vioxx was was tested on 5,000 people before it was approved, but many millions more took it after approval, when serious side effects like heart attacks began showing up.

If there is an unusually high number of reports on a drug, FDA will evaluate the claims and may request further studies, require changes to the drug’s labeling information, or rarely, remove the drug from the market, as with Vioxx.