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Medication therapy is becoming increasingly more complex as new drugs are developed and more therapeutic targets are elucidated. In addition, polypharmacy (≥5 scheduled medications) has become exceedingly common in geriatric patients and in patients with chronic disease states. As the complexity of drug therapy and the number of medications increase, patients are at a high risk for medication errors and adverse drug events (ADEs), or injuries resulting from medication. The National Coordinating Council for Medication Error Reporting and Prevention (NCC MERP) defines a medication error as “any preventable event that may cause or lead to inappropriate medication use or patient harm while the medication is in the control of the health care professional, patient, or consumer.”1 The Institute of Medicine (IOM) simplifies the definition by stating that a medication error is “any error occurring in the medication-use process.”2 Medication errors are particularly problematic when they lead to preventable ADEs, or injuries resulting from medication. The IOM estimated in 2006 that 25% of medication errors led to preventable ADEs. While the majority of ADEs are nonpreventable, it is still imperative that hospitalists recognize the seriousness of preventable ADEs and how these ADEs can be prevented.

Accounting for the true number of medication errors and ADEs is difficult since many go unrecognized or are not reported. Even though many databases are anonymous and nonpunitive, many professionals do not report medication errors and ADEs out of fear; institutions then cannot identify system failures and address the problems. In 2006, the IOM released Preventing Medication Errors: Quality Chasm Series and published staggering statistics about the number and cost of medication errors. The IOM estimated that each hospitalized patient experiences an average of one medication error daily. Though not all of these medication errors result in preventable ADEs, the IOM estimated that 1.5 million ADEs occur annually with 390,000–450,000 occurring within the hospital setting. Another study at a large academic medical center found that 2 of every 100 admitted patients experienced a preventable ADE resulting in $2.8 million in additional costs to the institution. Due to underreporting and underrecognition, these estimates likely under-estimate the true number of medication errors and ADEs. Billions of additional dollars are spent each year as a result of medication errors and preventable ADEs. Identifying common error types and implementing strategies that reduce preventable errors and ADEs are the first steps to reducing the number and cost of errors.

There are two ways to classify medication errors: commission errors that result from an action (ie, wrong dose or wrong route) and omission errors that result from no action (ie, missed doses or untreated indications). Both of these error types may occur during any step in the medication use process; however, most errors occur during prescribing and medication administration.

Prescribing Errors


Hospital prescribing errors occurred at a rate of 0.3 per patient per day as reported by ...

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