Skip Navigation U.S. Department of Health and Human Services
Agency for Healthcare Research Quality
Archive print banner

Feature Story

This information is for reference purposes only. It was current when produced and may now be outdated. Archive material is no longer maintained, and some links may not work. Persons with disabilities having difficulty accessing this information should contact us at: Let us know the nature of the problem, the Web address of what you want, and your contact information.

Please go to for current information.

System and equipment changes could reduce hospital medication errors

Adverse drug events (ADEs) cause nearly one out of five injuries or deaths to hospital patients each year. Although some ADEs are not preventable, those due to physician, nurse, or pharmacy error can be prevented. Overhauling the system rather than punishing personnel is the way to reduce these errors, according to two studies that were supported in part by the Agency for Health Care Policy and Research (HS07107). Findings from these studies indicate that many ADEs could be avoided if hospitals upgraded their computer systems, standardized drug ordering and administration procedures, and improved communication between departments.

Led by Lucian L. Leape, M.D., of the Harvard School of Public Health, researchers studied all adults admitted to 11 nursing units at two large Boston hospitals over a 6-month period from February through July 1993. Nurses and pharmacists reported incidents to nurse investigators, who also reviewed patient charts to detect actual or potential drug-related incidents. During this time, the researchers found 247 ADEs, of which 70 (28 percent) were preventable and 194 potential ADEs of which 83 (43 percent) were intercepted before the drug was given. The adjusted rates per 100 nonobstetric admissions were 6.5 for ADEs and 5.5 for potential ADEs. Errors resulting in preventable ADEs occurred most often at the stages of drug ordering (56 percent) and administration (34 percent). Errors in transcribing the doctor's order (6 percent) and pharmacy dispensing (4 percent) were less common.

As part of the study, the researchers performed a systems analysis to identify and evaluate the systems failures underlying the errors that caused the ADEs and potential ADEs. Dosing errors were by far the most common type of error, accounting for 28 percent of all errors. Most of the wrong-dose errors (50 of 95) occurred in the physician ordering stage and were primarily due to the physician's lack of knowledge about the drug or about the patient for whom it was prescribed.

The most common systems failure was in the dissemination of drug knowledge, particularly to physicians, accounting for 29 percent of errors. Inadequate availability of patient information, such as the results of laboratory tests, was associated with 18 percent of errors. Failures in seven hospital systems accounted for 78 percent of errors: drug knowledge dissemination, dose and identity checking, patient information availability, order transcription, allergy-alert system, medication order tracking, and interservice communication.

More details are in "Incidence of adverse drug events and potential adverse drug events," by David W. Bates, M.D., M.Sc., David J. Cullen, M.D., Nan Laird, Ph.D., and others, and in "Systems analysis of adverse drug events," by Dr. Leape, David W. Bates, M.D., M.Sc., David J. Cullen, M.D., and others, as well as a related editorial, "Above all 'do no harm:' How shall we avoid errors in medicine?" by Katherine L. Kahn, M.D., all of which appear in the July 5, 1995, issue of the Journal of the American Medical Association 274(1), pp. 29-34, 35-43, and 75-76.

Return to Contents
Proceed to Next Section

The information on this page is archived and provided for reference purposes only.


AHRQ Advancing Excellence in Health Care