At least 1.5 million Americans are injured or killed every year by medication errors at a direct cost of billions of dollars, according to a report issued Thursday by the prestigious Institute of Medicine in Washington, D.C.
For hospitalized patients, the report said that on average, one medication error per day was caused by confusion in drug names, wrong doses, failure to deliver drugs or a host of other problems.
The study is a follow-up to a 1999 report from the institute, which is part of the National Academies, that outlined all medical errors and claimed that as many as 98,000 people were killed each year as a result of medical errors -- 7,000 of them as a result of medication errors.
"We were initially quite surprised by the number of mistakes, but the more we heard, the more convinced we were that these are actually serious underestimates," said panel member Dr. Kevin Johnson of Vanderbilt University School of Medicine.
The study lays out a detailed series of recommendations for new procedures and research to minimize the risk of future medication errors, emphasizing computerization of prescribing and administering drugs and data acquisition.
Betsy Lehman, a health reporter for the Boston Globe, was one patient who was killed as a result of such errors, according to the report. The 39-year-old wife and mother of two was being treated for breast cancer in an experimental program at Boston's 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. Lehman died when nurses administered that total each day, overwhelming her system.
The hospital had no system 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.
Such mistakes happen all too frequently, the report said. Each year, there are an estimated 400,000 preventable drug-related injuries in hospitals, costing at least $3.5 billion.
There also are 800,000 medication-related injuries in nursing homes and other long-term care facilities, and about 530,000 among Medicare recipients in outpatient clinics. The report provided no estimate on the cost of the errors in those facilities.
"We've made significant improvements since 1999 ... but we still have a long way to go," said J. Lyle Bootman of the University of Arizona College of Pharmacy, who co-chaired the panel.
"The current process by which medications are prescribed, dispensed, administered and monitored is characterized by many serious problems that threaten both the safety and positive outcomes of patients."
With more than 4 billion prescriptions being 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 said. It cited a 2002 study from the United States Pharmacopeia that found these five drugs accounted for 28% 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 any more," said Dr. Wilson W. Pace of the University of Colorado.
Another is the similarity between drug names, which often results in the wrong drug being given. For example, the osteoporosis drug Fosamax could be mistaken for Flomax, which is given to improve urination in patients with an enlarged prostate.
Other problems cited by the panel include the legendary bad handwriting of physicians, nurses giving patients drugs meant for another patient, pharmacists dispensing the wrong drugs and patients not understanding how to take the drugs.
The report cites one middle-aged man who was not helped by his new asthma inhaler. Demonstrating how he used it, the man puffed the inhaler into the air in front of him and inhaled -- just as his doctor had done. Because the man was illiterate, he was not able to read the package instructions, which said to puff it directly into his lungs.
"If you are not sure of something, ask," said panelist Dr. Albert W. Wu of Johns Hopkins University. "It may be a little bit of an annoyance to providers, but we will get used to it."
The report said patients also share some of the blame, frequently withholding information about supplements and herbal medications that they are taking -- some of which can have serious interactions with prescription drugs. The panelists also noted studies showing that only about 55% of patients take all their drugs.