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Labelling and packaging practices: A summary of some of the evidence
Version 1.0, January 2013
Look-alike sound-alike errors
The existence of confusing drug names is considered one of the most common causes of medication error and is of concern worldwide, with many drug names looking or sounding like other drug names. It has been recognised by the WHO as a significant issue to be addressed (WHO, 2007).
There are numerous published examples of errors attributed to look-alike sound-alike names, labels and packaging (Teplitsky, 1969; Hargett et al, 1977; Lessard, Mathieu & Farfard, 1993; USP Quality Review, 2001; Drug Topics, 2003; Reines, 2005; Dunlop, 2009; Kay, 2011; O’Donoghue, 2012). A recent Australian review was conducted by Ostini et al (2012), with the objective of developing strategies to enhance patient safety and minimise clinical risk associated with look-alike sound-alike names. From the 32 publications reviewed, Ositini et al (2012) identified that a multi-faceted approach involving all aspects of the medication process, from manufacture, prescribing, dispensing and through to administration, is required to minimise the risks to consumer safety from this issue and labelling more broadly.
Table 1, from the review, summarises potential ways to minimise harm from medications.
The recommendation of a multifaceted approach is supported by the previous studies of Cohen (1995), Hoffman & Proulx (2003), Berman (2004) and Emmerton & Rizk (2012). All of these reviews recognised the risk potential at the various stages of the medication cycle and the need to consider behaviour at each step.
In the approvals stage of the medication cycle, electronic screening of look-alike sound-alike names is considered to be most effective using a combination of orthographic and phonetic measurements, such as that developed by Kondrak and Dorr (2006) and used by the US Food and Drug Administration. This approach to preventing medication errors caused by confusion between similar drug products is further analysed and discussed by Lambert et al (2004).
Prescribing and dispensing are the next steps in the medication cycle where errors may result from look-alike sound-alike names. As the likelihood of name confusion is reduced by the distinctiveness of the name, it has been suggested that use of the active ingredient and brand name, should be used when referring to medicines with known potential for confusion (Berman, 2004).
Tall man lettering is another method of differentiating confusable names, using capitalisation of letters within the medication name (Australian Commission on Safety and Quality in Healthcare, 2011a). A number of studies have been conducted to evaluate the effectiveness of tall man lettering in error reduction (Filik et al, 2004; Filik et al, 2006; Gabriele, 2006; Van de Vreede et al, 2008; Filik et al, 2010; ISMP, 2011; Australian Commission on Safety and Quality in Healthcare, 2011a). Many of these studies found that the use of tall man lettering may have reduced selection error due to similar names being easier to distinguish (Filik et al, 2004; Filik et al 2006; Van de Vreede et al, 2008). However, in many of these studies a standardised version of tall man lettering was not used, and capitalisation may have been applied in a variety of ways, and there was no consistency in the evaluation methods (Gerrett et al, 2009; Australian Commission on Safety and Quality in Healthcare, 2011b). Furthermore, the capitalisation was found to be only of real value when participants were aware of the purpose of tall man lettering (Filik et al, 2006; Gabriele, 2006; ISMP, 2011; Ostini, 2012). Concerns were also raised regarding the potential reduction in effectiveness of tall man lettering that may result if it is over-used (Gabriele, 2006; ISMP, 2011; Australian Commission on Safety and Quality in Healthcare, 2011b).
For these reasons the Australian Commission on Safety and Quality in Healthcare (2011a), recommended use of the National Tall Man Lettering Standard in prescribing and dispensing software to assist pharmacists and doctors reduce the risks associated with look-alike sound-alike drug names, but not more widely. Only medicine names included on the standard list of tall man names would be incorporated into medical software.
From a consumer perspective, the risk associated with look-alike sound-alike names, in the final step of the medication cycle, is best reduced through education and awareness, in particular in relation to the active ingredient, as well as the indication or illness a medicine for which a medicine is being taken (Ostini, 2012).
Australian Commission on Safety and Quality in Health Care, National Standard for the Application of Tall Man Lettering. Australian Commission on Safety and Quality in Health Care, Sydney 2011a.
Australian Commission on Safety and Quality in Health Care, Evaluating the Effect of the Australian List of Tall Man Names. Australian Commission on Safety and Quality in Health Care, Sydney 2011b.
Berman A, Reducing medication errors through naming, labelling and packaging. Journal of Medical Systems, 2004;28:9-29.
Ostini R, Roughead EE, Fitzpatrick CMJ, et al, Quality Use of Medicines – medication safety issues in naming; look-alike, sound-alike medicine names. International Journal of Pharmacy Practice 2012; doi: 10.1111/j.2042-7174.2012.00210.x (first published online 18 May 2012).
Cohen MR, Drug product characteristics that foster drug-use system-errors. Am J Health-Sys Pharm, 1995;52:395-399.
Dunlop C, Medicinal mishap: Atropt-Azopt Substitution, Australian Prescriber, 2009;32:138-139.
Emmerton LM & Rizk MFS, Look-alike and sound-alike medicines: risks and 'solutions'. Int J Clin Pharm, 2012;34:4-8.
FDA Safety Page, Generic Name Confusion, Drug Topics, 2003;October:90.
Filik R, Purdy K, Gale A & Gerrett, Drug name confusion: evaluating the effectiveness of capital ("Tall man") letters using eye movement data. Social Science & Medicine, 2004;59:2597-2601.
Filik R, Purdy K, Gale A & Gerrett, Labeling of medicines and patient safety: evaluating methods of reducing drug name confusion. Human Factors, 2006;48:39-47.
Filik R, Price J, Darker I, et al, The influence of Tall Man Lettering on drug name confusion. Drug Safety, 2012;33:677-687.
Gabriele S, The role of typography in differentiating look-alike/sound-alike names. Healthcare Quarterly, 2006;9 88-95.
Gerrett D, Gale AG, Darker IT et al, Tall Man Lettering Final Report of the use of tall man lettering to minimise selection errors of medicine names in computer prescribing and dispensing systems. ITQ Invitation Reference No: ER-07-0612. Loughborough University Enterprises Ltd. National Health Service, United Kingdom.
Hargett NA, Ritch R, Mardirossian J, et al, Inadvertent substitution of acetohexamide for acetazolamide. Am J Ophthamology, 1977;84:580-583.
Hoffman JM & Proulx, Medication errors caused by confusion of drug names. Drug Safety, 2003;26:445-452.
ISMP Medication Safety Alert, ISMP Updates is list of Drug Name Pairs with TALL Man Letters, ISMP Medication Safety Alert Posted 02/08/2011.
Kay, E (ed), Coversyl and Coumadin: new packaging to reduce potential for dispensing errors. Australian Prescriber, 2011;34:48.
Kondrak G & Dorr B, Automatic identification of confusable drug names. Artificial Intelligence in Medicine, 2006;36:29-42.
Lambert BL, Yu C, Thirumalai M, A system for multiattribute drug product comparison. Journal of Medical Systems, 2004;28:31-56.
Lessard MR, Mathieu M, Fafard M, Similarity of drug labels predisposes to drug errors. Can J Anaesth 1993;40:1109-11.
O'Donoghue N, Look-alike/sound-alike confusion could be lethal: study. Pharmacy News, 21 May 2012.
Reines SA, Look-alike sound-alike drug errors with Reminyl and Amaryl. Am J Health-Syst Pharm, 2005;62:35-36.
Tepltisky B, Confusing drug names. JAMA, 1969;207:2440.
US Pharmacopeia, USP Quality Review: Use Caution - Avoid Confusion, March 2001, No 76.
Van de Veerde M, McRae A, Wiseman M, Dooley MJ, Successful introduction of tallman letters to reduce medication selection errors in a hospital network. J Pharm Pract Res, 2008;38:263-266.
WHO Collaborating Centre for Patient Safety Solutions, Look-Alike Sound-Alike Medication Names. Patient Safety Solutions, 2007;1: Solution 1.