Insulin, warfarin and amoxicillin are involved the most.
CHICAGO (AP) -- 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 over 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 bad drug reactions are likely often misdiagnosed.
The study found that a small group of pharmaceutical warhorses were most commonly implicated, including insulin for diabetes; warfarin for clotting problems; and amoxicillin, a penicillin-like antibiotic used for all kinds of infections.
Those aged 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 2004-05, 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 Wednesday's Journal of the American Medical Association.
The database included 63 nationally representative hospitals that reported 21,298 bad 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 it translates to 701,547 complications nationwide each year.
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.
"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."
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