By PPN Staff

The Institute for Safe Medication Practices (ISMP) recently updated its list of drug names with tall man (mixed case) letters based on the results of a survey of healthcare providers.


Tall man lettering is used to differentiate unique letter characters of similar drug names that have been confused with one another, by capitalizing dissimilar letters. 

“The use of tall man lettering to accentuate a unique portion of a drug name with UPPERCASE letters, along with other means such as color, bolding or a contrasting background, can draw attention to the dissimilarities between look-alike drug names as well as alert healthcare providers that the drug name can be confused with another drug name,” the organization wrote.

 
The ISMP has maintained a list of drug names with uppercase and bolded tall man letters since 2008, which includes generic-generic drug name groupings as well as a few brand-brand or brand-generic name pairs. To help update the list, the organization conducted a survey between October and December 2022 of 298 healthcare providers, including pharmacists (57%), nurses (24%), pharmacy technicians (12%), physicians and other prescribers (2%), and others such as consultants and respiratory therapists (5%). 

The results indicated that tall man letters were widely used: 94% of respondents reported that their facility uses tall man letters, 74% consistently use tall man letters for organization-defined drug names in all required contexts (such as computer screens for pharmacy and prescribers), and 80% use tall man letters in all settings (such as pharmacy and surgical suites) and across multiple-facility settings. 

Additionally, the ISMP found that 95% of respondents thought tall man letters on product and carton labels helped to reduce drug selection errors, and 87% of survey respondents could recall one or more instances when tall man lettering prevented them from prescribing, transcribing, dispensing or administering the wrong medication. 

Examples of look-alike name pairs involved in these potential events included hydralazine and hydrOXYzine, levETIRAcetam and levoFLOXacin, and SOLU-Medrol and DEPO-Medrol. 

“Several respondents also told us that tall man lettering alerts them to the possibility of a drug mix-up, reminding them to be cautious,” the ISMP wrote. “They said that tall man letters are an effective alert system that quickly captures their attention and causes them to pause, read the drug name more carefully a second or third time, and make sure the drug is appropriate for the patient.” 

In the survey, the organization asked for feedback on 10 potential new drug name pairs or single drug names that might be confused with a drug name pair already on the list. Ultimately, the ISMP added the following drug names to its list:

• cycloPHOSphamide (confused with cycloSPORINE and cycloSERINE, already on the FDA list)
• droPERidol and droNABinol
• dexAMETHasone and dexmedeTOMIDine
• pyRIDostigmine and PHYSostigmine


Additionally, the ISMP reviewed respondents’ suggestions regarding other drug names not tested in the survey that could be confused with names already on the list. Based on this evaluation, the organization added the following names to its list:

• ALfentanil (confused with SUFentanil and fentaNYL, already on the ISMP list)
• BUPivacaine and ROPivacaine
• oxyBUTYnin (confused with oxyCODONE, OxyCONTIN and oxyMORphone, already on the ISMP list)

The ISMP also removed three name pairs that included brand names of discontinued drugs from the list:

• AVINza (discontinued) and INVanz
• SINEquan (discontinued) and SEROquel
• TRENtal (discontinued) and TEGretol

The ISMP also updated the list to include a medication that is not currently available in the United States:
• raNITIdine (not available) confused with riMANTAdine

The updated FDA and ISMP Lists of Look-Alike Drug Names with Recommended Tall Man (Mixed Case) Letters can be found on the ISMP website.