1.5 million Americans a year affected by medication errors

WASHINGTON — At least 1.5 million Americans are sickened, injured or killed each year by avoidable errors in prescribing, dispensing and taking medications, the influential Institute of Medicine concludes in a major report released Thursday.

Mistakes in giving drugs are so prevalent in hospitals that, on average, a patient will be subjected to a medication error each day he or she fills a hospital bed, the report says.

Following up on its 2000 report on medical errors of all kinds, the institute, a branch of the National Academy of Sciences, undertook the most extensive study ever of medication errors at the request of Congress when it passed the Medicare Modernization Act in 2003.

The report found errors to be not only harmful and widespread, but costly as well. The extra medical cost of treating drug-related injuries occurring only in hospitals was estimated to be at least $3.5 billion a year.

"The frequency of medication errors and preventable adverse drug events is cause for serious concern," said Linda Cronenwett, dean of the School of Nursing at the University of North Carolina at Chapel Hill, and co-chair of the panel that researched the report. She and other panel members said the problem requires immediate action.

"Everyone in the health-care system knows this is a major problem, but there's been very little action and it's generally remained on the back burner," panel member Charles Inlander said. "With this report, we hope to give everyone involved good, hard information on how they can prevent medication errors, and then create some pressure to have them implement it."

The report endorsed much wider use of electronic prescribing, which it says reduces errors, and encouraged technology improvements so the many computer programs used by doctors, hospitals and drugstores are compatible.

The errors the institute studied included doctors writing illegible prescriptions, nurses giving one patient medication intended for another, and a local pharmacist dispensing 100-milligram pills rather than the prescribed 50 milligrams.

The report spotlighted the case of Betsy Lehman, a health reporter for The Boston Globe. The 39-year-old wife and mother of two was being treated for breast cancer in an experimental program at the Dana-Farber Cancer Institute in 1994.

A medical fellow wrote a prescription for the cancer drugs citing the total amount she was to receive over four days, the report said. She died when nurses administered that total each day, overwhelming her system. The hospital had no system in place to monitor dosages, and her family argued that staff did not pay attention to her complaints about the effects of the overdose, according to the report.

The report did not address whether some drugs should be pulled from the market because of their intrinsic risks or whether the Food and Drug Administration does an adequate job of ensuring that approved drugs are safe for general use. That is the subject of another study expected to be released soon by the institute.

With more than 4 billion prescriptions written each year in the United States, even a very small error rate can translate into a large number of problems.

Among the drugs most commonly associated with errors in hospitals are insulin, morphine, potassium chloride and the anticoagulants heparin and warfarin, which have a high risk of patient injury when dispensed incorrectly.

The report cited a 2002 study from the United States Pharmacopeia that found that these five drugs accounted for 28 percent of all errors that resulted in extended hospitalizations. Insulin alone accounted for a third of that total.

The panel cited a variety of causes for the problems.

One is unexpected drug interactions. With more than 15,000 prescription drugs in use and 300,000 over-the-counter products, "it is virtually impossible for a human to track all the interactions anymore," said Dr. Wilson Pace of the University of Colorado.

Another is the similarity between drug names, which often results in the wrong drug being given. For example, Fosamax, the osteoporosis drug, could be mistaken for Flomax, given to improve urination in patients with an enlarged prostate.

Other problems include patients not understanding how to take the drugs.

The report said errors in hospitals and long-term-care facilities generally are not reported to patients or family members unless they result in injury or death. The panel said all health-care organizations should report medication errors to patients whether they cause harm or not.

Based on existing studies, the panel estimated that drug errors cause at least 400,000 preventable injuries and deaths in hospitals each year, more than 800,000 in nursing homes and facilities for the elderly, and 530,000 among Medicare recipients treated in outpatient clinics. The report said the actual numbers are likely much higher.

Inlander, president of the People's Medical Society, a Pennsylvania consumer-health advocacy group, said that the institute panel sought information about how many people may have died as a result of drug errors, but that the estimates were so different — from 7,000 to 50,000 a year — that they were not included in the report.