Adverse Drug Reactions Cause 1.4 Million Emergency Room Visits in 2004 and 2005

Recent research found that hundreds of thousands of people, many of them elderly, have been treated in emergency rooms for adverse drug reactions such as allergic reactions, unintentional overdoses, or other complications related to the use of prescribed drugs. The findings were published in the October 18, 2006, issue of the Journal of the American Medical Association.

An estimated 701,547 patients were treated for adverse drug reactions in emergency rooms each year in 2004 and 2005, totaling 1.4 million visits to the emergency room. Of these, an estimated 117,318 patients were hospitalized each year, according to the study, which was funded by the Federal Centers for Disease Control and Prevention (CDC), the Food and Drug Administration (FDA), and the U.S. Consumer Products Safety Commission (CPSC).

A majority of emergency room visits were accounted for by two major kinds of problems. About one-third were the result of allergic reactions to drugs and another third were caused by unintentional overdoses.

Most of the emergency room visits that required hospitalization were due to unintentional overdoses.

These estimates were determined by using a national tracking system called the National Electronic Injury Surveillance System — Cooperative Adverse Drug Event Surveillance (NEISS-CADES). NEISS-CADES was developed by the CDC, FDA and CPSC to estimate the number of patients who visit emergency rooms annually because of adverse drug reactions. The system bases its estimates on information from 63 representative hospitals around the United States.

Drugs Most Frequently Implicated in Adverse Events

Overall, the five families of drugs most likely to cause adverse events in this study were insulins, painkillers containing narcotics, anticoagulants, antibiotics containing amoxicillin, and antihistamine cold products. These families of drugs accounted for about 28 percent of the adverse drug events.

According to the federal research, 18 drugs were each, either independently or in combination with other drugs, implicated in one percent or more of the estimated adverse drug events. These drugs are listed in the table that accompanies this article along with the annual estimates of adverse drug events.

The NEISS-CADES data also showed that drugs that routinely require monitoring to prevent acute toxicity were involved in 66 percent of unintentional overdoses requiring hospitalization. These drugs include antidiabetic drugs such as metformin (GLUCOPHAGE); the blood thinner warfarin (COUMADIN); heart drugs that regulate the rate and strength of the heartbeat (digitalis) such as digoxin (LANOXIN); theophylline, an asthma drug used less-commonly today than in the past; and lithium (LITHOBID), a drug used for manic depressive illness. In patients 65 or older, these drugs were responsible for more than 87 percent of the overdoses requiring hospitalizations.

What You Can Do

If you have been prescribed one of the drugs listed in the table above — or any drug, for that matter — check Public Citizen’s best-selling book Worst Pills, Best Pills; Worst Pills, Best Pills News; or this site, www.worstpills.org, before taking it. Use these tools to read about possible drug reactions and learn what steps to take should an adverse drug reaction develop.