Medication errors


From Rx-wiki

A medication error is any incorrect or wrongful administration of a medication, such as a mistake in dosage or route of administration, failure to prescribe or administer the correct drug or formulation for a particular disease or condition, use of outdated drugs, failure to observe the correct time for administration of the drug, or lack of awareness of adverse effects of certain drug combinations. Causes of medication error may include difficulty in reading handwritten orders, confusion about different drugs with similar names, and lack of information about a patient's drug allergies or sensitivities.

The National Coordinating Council for Medication Error Reporting and Prevention (NCC MERP) has organized medication errors into four major groupings encompassing a total of nine categories (categories A through I):

  • No Error
    • Category A: Circumstances or events that have the capacity to cause error
  • Error, No Harm
    • Category B: An error occurred but the error did not reach the patient (An "error of omission" does reach the patient)
    • Category C: An error occurred that reached the patient but did not cause patient harm
    • Category D: An error occurred that reached the patient and required monitoring to confirm that it resulted in no harm to the patient and/or required intervention to preclude harm
  • Error, Harm
    • Category E: An error occurred that may have contributed to or resulted in temporary harm to the patient and required intervention
    • Category F: An error occurred that may have contributed to or resulted in temporary harm to the patient and required initial or prolonged hospitalization
    • Category G: An error occurred that may have contributed to or resulted in permanent patient harm
    • Category H: An error occurred that required intervention necessary to sustain life
  • Error, Death
    • Category I: An error occurred that may have contributed to or resulted in the patient’s death

Prescription error facts

The following are some sobering facts related to medication errors.

  • The Institute of Medicine (IOM) estimates that up to 98,000 people die annually in the United States from medical errors and does not include those seriously injured.
  • To go further, a study conducted by The Leapfrog Group estimates that 7,000 of these deaths are due to medication errors.
  • According to Franklin et al, 1.5 million people in the United States are sickened, injured, or killed each year due to prescription errors.

Causes of errors

According to a study of prescription errors conducted by MEDMARX and released in 2005, the following is a quick breakdown about the causes of these errors:

  • Performance deficit (failure to act in accordance with education and training)- 38%
  • Procedure/protocol not followed - 17%
  • Transcription inaccurate/omitted - 13%
  • Computer entry - 12%
  • Documentation lacking/inaccurate - 12%
  • Knowledge deficit - 10%
  • Communication - 9%

Error reporting

The National Medication Errors Reporting Program, operated by the Institute for Safe Medication Practices (ISMP MERP), is a confidential voluntary program that provides expert analysis of system-based causes of medication errors. Through various media outlets, the Institute for Safe Medication Practices (ISMP) communicates recommendations for improving safety. ISMP MERP's voluntary reporting is available at

It is also useful to report medication misadventures to the Food and Drug Administration's MedWatch program at, excluding vaccines. Adverse events involving vaccines should be reported to Vaccine Adverse Event Reporting System (VAERS) at which is ran by both the FDA and the CDC. Much like ISMP MERP, MedWatch is also voluntary, but VAERS is actually mandatory.

Error prevention

There are a broad array of error prevention tools out there including using the five rights (some times also expanded to the seven rights), using extra precautions with respect to high-alert medications, adopting system wide use of Tallman lettering, avoiding error prone abbreviations, and using barcoding technology.

See also

Five rights
Drug recalls
Vaccine Adverse Event Reporting System
Tallman lettering
High-alert medications
Barcoding technologies
Risk evaluation and mitigation strategies
Patient package insert
Medication safety


  1. TheFreeDictionary, Medication error,
  2. NCC MERP, NCC MERP Index for Categorizing Medication Errors,
  3. To Err Is Human, Building a Safer Health System, Linda T. Kohn, Janet M. Corrigan, and Molla S. Donaldson, 2000
  4. JAMA, Incidence of Adverse Drug Events and Potential Adverse Drug Events. Implications for Prevention, DW Bates et al, vol 274, pp 29-34, 1995
  5. Drug Saf, The incidence of prescribing errors in hospital inpatients, BD Franklin, C Vincent, M Schachtner, N Barber, vol 28, pp 891-900, 2005
  6. The Commonwealth Fund, Medication Mistakes: Types and Causes,