Bad drug reactions send 700,000 to ER each year

CHICAGO — Harmful reactions to some of the most widely used medicines — from insulin to a common antibiotic — sent more than 700,000 Americans to emergency rooms each year, landmark government research shows.

Accidental overdoses and allergic reactions to prescription drugs were the most frequent cause of serious illnesses, according to the study, the first to reveal the nationwide scope of the problem. People older than 65 faced the greatest risks.

“This is an important study because it reinforces the really substantial risks that there are in everyday use of drugs,” said patient-safety specialist Bruce Lambert, a professor at the University of Illinois at Chicago’s college of pharmacy.

Even so, the study authors and other experts agreed that the 700,000 estimate was conservative because severe drug reactions can often be misdiagnosed.

The study found that a small group of pharmaceutical mainstays was most commonly implicated, including insulin for diabetes; warfarin for clotting problems; and amoxicillin, a penicillinlike antibiotic used for all kinds of infections.

“These are old drugs, which are known to be extremely effective. We could not and would not want to live without them. But you’ve got to get the dose exactly right,” Mr. Lambert said. He was not involved in the research.

Those 65 and older faced more than double the risk of requiring emergency-room treatment and were nearly seven times more likely to be admitted to the hospital than younger patients.

The results, from 2004 to ‘05, represent the first two years of data from a national surveillance project on outpatient drug safety. The project was developed by the federal Centers for Disease Control and Prevention, the Food and Drug Administration and the U.S. Consumer Product Safety Commission. The study was published in today’s Journal of the American Medical Association.

The database included 63 nationally representative hospitals that reported 21,298 severe drug reactions among U.S. adults and children treated in emergency rooms during the two-year period. The tally is based on what emergency-room doctors said were complications from using prescription drugs, over-the-counter medicines, dietary supplements or herbal treatments.

The researchers said that when those numbers are extrapolated, it brings the total to 701,547 complications nationwide each year.

“Experts had thought that severe outpatient drug events were common, but no one really had good numbers” until now, said lead author Dr. Daniel Budnitz, a CDC researcher.

Complications included diabetics on insulin passing out from low blood sugar, excessive bleeding in patients on warfarin, and severe skin rashes in patients taking amoxicillin. Drug reactions were severe enough to require hospitalization in about 17 percent of patients.

“The numbers are quite troubling,” said Jim Conway, senior vice president at the Institute for Healthcare Improvement. The tally underscores that “there is a tremendous number of consumers in the United States taking medication.”