Medication-prescribing errors in a teaching hospital. A 9-year experience

Improved understanding of medication prescribing errors should be useful in the design of error prevention strategies.

To report analysis of a 9-year experience with a systematic program of detecting, recording, and evaluating medication-prescribing errors in a teaching hospital.

All medication-prescribing errors with potential for adverse patient outcome detected and averted by staff pharmacists from January 1, 1987, through December 31, 1995, were systematically recorded and analyzed. Errors were evaluated by type of error, medication class involved, prescribing service, potential severity, time of day, and month. Data were analyzed to determine changes in medication-prescribing error frequency and characteristics occurring during the 9-year study period.

A total of 11,186 confirmed medication-prescribing errors with potential for adverse patient consequences were detected and averted during the study period. The annual number of errors detected increased from 522 in the index year 1987 to 2115 in 1995. The rate of errors occurring per order written, per admission, and per patient-day, all increased significantly during the study duration (P < .001). Increased error rates were correlated with the number of admissions (P < .001). Antimicrobials, cardiovascular agents, gastrointestinal agents, and narcotics were the most common medication classes involved in errors. The most common type of errors were dosing errors, prescribing medications to which the patient was allergic, and prescribing inappropriate dosage forms.

The results of this study suggest there may exist a progressively increasing risk of adverse drug events for hospitalized patients. The increased rate of errors is possibly associated with increases in the intensity of medical care and use of drug therapy. Limited changes in the characteristics of prescribing errors occurred, as similar type errors were found to be repeated with increasing frequency. New errors were encountered as new drug therapies were introduced. Health care practitioners and health care systems must incorporate adequate error reduction, prevention, and detection mechanisms into the routine provision of care.