How many hospital pharmacy medication dispensing errors go undetected?

Jt Comm J Qual Patient Saf. 2006 Feb;32(2):73-80. doi: 10.1016/s1553-7250(06)32010-7.


Background: Hospital pharmacies dispense large numbers of medication doses for hospitalized patients. A study was conducted at an academic tertiary care hospital to characterize the incidence and severity of medication dispensing errors in a hospital pharmacy.

Methods: Direct observation of dispensing processes was undertaken to determine presence of errors with review by a physician panel to determine severity.

Results: A total of 140,755 medication doses filled by pharmacy technicians were observed during a seven-month period, and 3.6% (5075) contalned errors. The hospital pharmacist detected only 79% of these errors during routine verification; thus, 0.75% of doses filled would have left the phannacy with undetected errors. Overall, 23.5% of undetected errors were potential adverse drug events (ADEs), of which 28% were serious and 0.8% were life threatening. The most common potential ADEs were incorrect medications (36%), incorrect strength (35%), and incorrect dosage form (21%).

Discussion: Given the volume of medications dispensed, even a low rate of drug distribution process translates into a large number of errors with potential to harm patients. Pharmacy distribution systems require further process redesign to achieve the highest possible level of safety and reliability.

Publication types

  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Academic Medical Centers
  • Boston
  • Humans
  • Iatrogenic Disease / epidemiology
  • Incidence
  • Medical Audit*
  • Medication Errors / classification
  • Medication Errors / prevention & control
  • Medication Errors / statistics & numerical data*
  • Medication Systems, Hospital / standards*
  • Pharmacy Service, Hospital / standards*
  • Pharmacy Service, Hospital / statistics & numerical data
  • Process Assessment, Health Care
  • Safety Management*
  • Task Performance and Analysis