Drug Safety

, Volume 33, Issue 8, pp 677–687 | Cite as

The Influence of Tall Man Lettering on Drug Name Confusion

A Laboratory-Based Investigation in the UK Using Younger and Older Adults and Healthcare Practitioners
  • Ruth Filik
  • Jessica Price
  • Iain Darker
  • David Gerrett
  • Kevin Purdy
  • Alastair Gale
Original Research Article


Background: Medication errors commonly involve confusion between drugs with similar names. One possible method of reducing error is to emphasize differences between the names using ‘Tall Man’ (uppercase) letters (e.g. cef-TAZidime vs cefUROxime). Previous studies investigating this issue have been conducted mainly on university students, and results have been mixed.

Objective: To investigate the influence of Tall Man lettering on drug name confusion in other key participant groups.

Study Design: Two separate experiments were conducted. In Experiment 1 (conducted at the University of Glasgow, Scotland, between January 2008 and May 2008), younger and older adults performed a same/different judgement task. In Experiment 2 (conducted at various sites in England between December 2008 and February 2009), healthcare practitioners performed a task based on electronic prescribing.

Results: In Experiment 1, both younger and older adults made fewer name confusion errors when names contained Tall Man letters. Response times suggested that Tall Man lettering drew participants’ attention to those letters, but that readers did not solely rely on these letters in making their response. In Experiment 2, healthcare practitioners made fewer name confusion errors when the names contained Tall Man letters.

Conclusions: Overall, results showed that Tall Man lettering reduced drug name confusion errors in a series of laboratory-based tasks, in both younger and older adults, and healthcare practitioners. Thus, the current findings offer some support for the use of Tall Man letters as a possible systems change that could be made by both pharmacies and manufacturers in an effort to reduce error caused by drug name confusion.


National Health Service Simple Main Effect Chlorpropamide Healthcare Practitioner Natural Case 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.



No funding was received for the conduct of Experiment 1. Experiment 2 was supported by funding from the UK NHS Connecting for Health initiative. The funding organization specified the issue to be investigated and advised on drug names that are often involved in error, but were otherwise not involved in the conduct of the study, interpretation of results or preparation of the manuscript. David Gerrett received consultancy remuneration to undertake specific tasks for this research. He continues to collaborate with the research team and is now working with the National Patient Safety Agency, which has an interest in furthering knowledge in this area. All other authors have no potential conflicts of interest to declare that are directly relevant to the content of this study.

Supplementary material

40264_2012_33080677_MOESM1_ESM.pdf (56 kb)
Supplementary material, approximately 57 KB.


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Copyright information

© Adis Data Information BV 2010

Authors and Affiliations

  • Ruth Filik
    • 1
  • Jessica Price
    • 2
  • Iain Darker
    • 3
  • David Gerrett
    • 4
  • Kevin Purdy
    • 3
  • Alastair Gale
    • 3
  1. 1.School of PsychologyUniversity of NottinghamUniversity ParkUK
  2. 2.Bioengineering UnitUniversity of StrathclydeGlasgowUK
  3. 3.Applied Vision Research CentreUniversity of LoughboroughLoughboroughUK
  4. 4.National Patient Safety AgencyLondonUK

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