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What’s New in the Patient Safety World

July 2022

Five-Character Drug Search Has Problems, Too



In our April 12, 2022 Patient Safety Tip of the Week “A Healthcare Worker’s Worst Fear” we mentioned that, after the Vanderbilt neuromuscular blocking agent (NMBA) case, ISMP began recommending the entry of a minimum of five characters of a drug name during searches in ADC’s. ISMP’s “Guidelines for Safe Electronic Communication of Medication Information” also include that requirement for medication searches on other forms of electronic communication.


But ISMP also has seen reports where even entry of 5 letters has been associated with errors (ISMP 2021). For example:

·       You can still make a misspelling error in the first 5 characters of a drug’s name.

·       Some people have entered spaces or symbols to meet the 5-character requirement.

·       Combination drugs or parenteral fluids have been difficult to locate.

·       Some drugs are known by several different names.

·       In an emergency, some have forgotten the new requirement and entered fewer than 5 characters and been unable to promptly retrieve the emergency drug.

·       Some practitioners, unable to find their intended product, may scroll through an entire list of drugs using the inventory function rather than searching for a specific drug, a practice considered unsafe and time-consuming by ISMP.


ISMP offers some potential solutions:

·       For drug names with the same beginning characters beyond five letters, you might want to consider adding the therapeutic class to the drug name listing to help avoid drug selection errors (e.g., methylPREDNISolone [corticosteroid], methylphenidate [stimulant], methylnaltrexone [gastrointestinal agent], methylergonovine [ergot derivative]).

·       It is also reasonable to consider creating an alias/synonym for certain drugs on the override list that are commonly known by an alias/synonym. For example, NSS <space> <space> may be created as an alias for 0.9% sodium chloride solution. But each synonym created should be reviewed against other aliases/synonyms to ensure they are not too similar. 

·       ISMP also notes it might be safest to allow simultaneous drug name searches by the current brand and generic name. You’ll recall in the Vanderbilt NMBA incident, letters of a brandname drug were entered when the ADC only had the generic name.


There have also been suggestions that vendor functionality should be more tailored and specific to individual, problematic drugs that require the five-character search via override, rather than requiring an all-inclusive change for all drug name searches via override. Another suggestion is to allow users to “opt out” certain drugs from the five-character search rule but ISMP notes that could be confusing to require two different levels of drug name searches. ISMP also suggests that vendors might develop algorithms that would allow users to enter the exact number of characters to get only one unique drug name to appear on the screen, making emergency kits and key emergency drugs always accessible (ISMP notes that a separate code cart should always be maintained for emergency equipment and drugs to use during a cardiac and/or respiratory arrest).


As a precaution, ISMP recommends that before implementing the five-character search requirement for medications obtained from an ADC via override, hospitals should analyze the workflow, especially the searchability of emergency medications, and conduct a failure mode and effects analysis (FMEA) to identify and manage potential challenges (the ISMP article has some nice examples of risk points to consider during the FMEA). Prior to implementation, organizations must develop a robust and effective communication plan, and obtain feedback from frontline staff. After any changes, collect data to assess whether unintended consequences are occurring and make appropriate adjustments if needed.


And ISMP strongly recommends that, whenever possible, orders should be entered and verified by a pharmacist to allow medication or product removal within the patient’s profile, bypassing the requirement to enter five characters and limiting the necessity for ADC overrides.


The 5-letter entry requirement for drug searches on ADC’s or CPOE or any electronic medication system is certainly a step in the right direction. ISMP has done its usual great job of identifying barriers, challenges, and potential unintended consequences to implementing this important patient safety intervention.



Our prior columns related to ADC’s (automated dispensing cabinets):

December 2007           1000-fold Heparin Overdoses Back in the News Again

August 23, 2016         ISMP Canada: Automation Bias and Automation Complacency

December 11, 2018     Another NMBA Accident

January 1, 2019           More on Automated Dispensing Cabinet (ADC) Safety

February 12, 2019       From Tragedy to Travesty of Justice

April 2019                   ISMP on Designing Effective Warnings

June 11, 2019              ISMP’s Grissinger on Overreliance on Technology

September 7, 2021      The Vanderbilt Tragedy Gets Uglier

April 12, 2022             A Healthcare Worker’s Worst Fear






ISMP (Institute for Safe Medication Practices). Guidelines for Safe Electronic Communication of Medication Information. ISMP 2019; January 16, 2019



ISMP (Institute for Safe Medication Practices). Challenges with Requiring Five Characters During ADC Drug Searches Via Override. ISMP Medication Safety Alert! Acute Care Edition 2021; October 21, 2021





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