The Pattern of Abbreviation Use in Prescriptions: A Way Forward in Eliminating Error-Prone Abbreviations and Standardisation of Prescriptions

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1 Send Orders for Reprints to Current Drug Safety, 2014, 9, The Pattern of Abbreviation Use in Prescriptions: A Way Forward in Eliminating Error-Prone Abbreviations and Standardisation of Prescriptions N.R. Samaranayake *,1,2, P.R.L. Dabare 2, C.A. Wanigatunge 3 and B.M.Y. Cheung 1 1 Department of Medicine, Faculty of Medicine, The University of Hong Kong, Hong Kong 2 Department of Medical Education and Health Sciences, Faculty of Medical Sciences, University of Sri Jayewardenepura, Sri Lanka 3 Department of Pharmacology, Faculty of Medical Sciences, University of Sri Jayewardenepura, Sri Lanka Abstract: Introduction and Objectives: Inappropriate abbreviations used in prescriptions have led to medication errors. We investigated the use of error-prone and other unapproved abbreviations in prescriptions, and assessed the attitudes of pharmacists on this issue. Methods: A reference list of error-prone abbreviations was developed. Prescriptions of outpatients and specialty clinic patients in a teaching hospital in Sri Lanka were reviewed during one month. An interviewer administered questionnaire was used to assess attitudes of pharmacists. Results: 3370 drug items (989 prescriptions) were reviewed. The mean (standard deviation) number of abbreviations per prescription was 5.9 (3.5). The error-prone abbreviations used in the hospital were, µg (microgram), mcg (microgram), u (units), cc (cubic centimeter), OD (once a sign, d (days/daily), m (morning) and n (night), and among all prescriptions reviewed, they were used at a rate of 17.4%, 0.1%, 1.9%, 0.2%, 0.2%, 4.9%, 23.5%, 4.4% and 15.8% respectively. Among the 103 types of abbreviations observed, 71 were not standard acceptable abbreviations. Multiple abbreviations were used to indicate a single drug item/ instruction (N = 7). The abbreviation d was used to denote daily as well as days. All pharmacists believed that using error-prone abbreviations will always (5.3%) or sometimes (94.7%) lead to medication errors. Conclusions: Error-prone abbreviations and many other unapproved abbreviations are frequently used in hospitals. There is a need to educating health care professionals on this issue and introduce an in-house error-prone abbreviation list for their guidance. Keywords: 'Do Not Use' list, error-prone abbreviations, Medication errors, prescriptions; Sri Lanka, unapproved abbreviations INTRODUCTION The use of inappropriate abbreviations in prescriptions may alter intended therapeutic outcomes and even cause unnecessary harm to patients [1, 2]. Many safety organisations have cautioned this malpractice and have even highlighted some abbreviations that are frequently associated with medication errors [3-5]. Despite these warnings, errorprone abbreviations continue to be used [6]. The rapid evolvement of electronic prescriptions have minimised this problem to an extent [7], but hand-written prescriptions will continue to be used, especially in developing countries [8, 9]. Therefore eliminating error-prone abbreviations and standardising acceptable abbreviations is an urgent need. In order to achieve this goal, it is first important to identify the types and frequencies of inappropriate abbreviations used in prescriptions. Secondly, it is important to assess the attitudes of prescription interpreters, mainly *Address correspondence to this author at the Department of Medical Education and Health Sciences, Faculty of Medical Sciences, University of Sri Jayewardenepura, Sri Lanka; Tel: ; nithushisamaranayake@yahoo.com pharmacists, to determine the difficulties associated with reading and interpreting abbreviations. Unfortunately, abbreviations are not used consistently and may differ by country, setting or hospital [10-13]. Therefore, even if similar studies exist, these findings may not be completely applicable to all settings. Many safety organisations have introduced Do Not Use lists; lists that specify error-prone abbreviations that should be avoided by doctors when prescribing [3-5]. Although our previous work has suggested that this intervention is effective [14], the success would largely depend on introducing a comprehensive error-prone abbreviation list that would target inappropriate practices of a particular setting. As the pattern of using abbreviations vary among different settings, directly adopting error-prone abbreviation lists from other countries may not always be appropriate. Therefore we first compared error-prone abbreviations lists introduced by several internationals safety organisations [3-5, 15] in order to compile a comprehensive reference list. Using this reference, we aimed to identify error-prone abbreviations used in prescriptions of the study hospital. We also aimed to identify other potentially dangerous unapproved abbreviations (not listed as error-prone /14 $ Bentham Science Publishers

2 2 Current Drug Safety, 2014, Vol. 9, No. 1 Samaranayake et al. abbreviations), identify multiple abbreviations used to denote the same drug or instruction, and to identify instances where a single abbreviation has multiple intended meanings. We then aimed to ascertain attitudes of pharmacists regarding the use of inappropriate abbreviations in prescriptions. Using this information, we aimed to determine the suitability of developing an in-house error-prone abbreviation list against directly adopting lists recommended in other countries. METHODS The study was conducted in a university affiliated tertiary care hospital (herein after referred to as the study hospital) with 34 wards, 7 specialty units, 12 operating theaters and a bed strength of 1073 beds. Apart from the in-patient care, the hospital s out-patient services include the operation of 35 specialty clinics, accident & emergency, trauma and outpatient care department (OPD). The pharmacy department is mainly divided as indoor and outdoor pharmacies. The outdoor pharmacy dispenses drugs to the clinic patients and OPD patients, while the indoor pharmacy distributes drugs to the wards. As the hospital adopts a ward-stock method of drug distribution, pharmacists in the indoor pharmacy do not come into direct contact with prescriptions. Therefore only prescriptions and pharmacists related to the outdoor pharmacy were included in this study. We included prescriptions dispensed to OPD patients and 13 specialty clinics (medical, surgery, cardiology, neurology, endocrinology, skin, diabetes, peadiatrics, psychiatry, gastroenterology, cancer, asthma and hypertension clinic). THE STUDY PROCESS Development of an Error-Prone Abbreviations Reference List Error-prone abbreviations introduced by the Institute of Safe Medication Practices [3], the Joint Commission on Accreditation of Healthcare Organizations of the USA [4], Hospital Authority of Hong Kong SAR [15] and Australian Commission on Safety and Quality in Healthcare [5] were compared and a reference list of error-prone abbreviations was prepared by the study pharmacists. The comparison of error-prone and standard abbreviations introduced by different safety organisations are shown in Table 1. According to the comparison, the Institute of Safe Medication Practices [3] and the Australian Commission on Safety and Quality in Healthcare [5] introduced a wide list of error-prone abbreviations compared to the lists introduced by the Joint Commission [4] and the Hospital Authority of Hong Kong. Of note, abbreviations IU (international units), QD (once daily), QOD (every other day), u (units), trailing zero and lack of leading zero were highlighted by all four lists. µg (microgram) and OD (once daily) were highlighted in three lists. The reference list of error-prone abbreviations developed for this study incorporated abbreviations specified in all four lists (Table 2a). Two clinical pharmacologists reviewed and endorsed the reference list. The Prescription Review Process Abbreviations used in prescriptions were reviewed by two study pharmacists and were recorded in a predetermined data collection form. Abbreviations used for indicating drug names, instructions, route of administration and frequencies were documented. The prescriptions were randomly selected at any stage during the dispensing cycle. Prescriptions applicable to the latest clinic date were reviewed in patients who maintained a clinic book, and all reviewed prescriptions were tagged to avoid selecting the same prescription again. The audit was conducted for a period of one month on weekdays. Conducting the study for one month ensured that a representative sample of all clinic prescriptions was included, as generally all clinic patients revisit the clinic once a month. A sample of 50 prescriptions was reviewed and recorded by both study pharmacists, the records were compared and % of agreement was calculated using the kappa value. Discrepancies were discussed and a uniform method of interpreting prescriptions and recording were agreed upon. This ensured that variances in the ability to read and interpret handwritten prescriptions did not differ among the two study pharmacists. Error-prone abbreviations were determined according to the developed reference list. Abbreviations that were not categorised as error-prone, but did not comply with, the standard abbreviation list of the Hospital Authority of Hong Kong (Table 2b), and the list of acceptable terms or abbreviations of the Australian Commission on Safety and Quality in Healthcare [5] were grouped as other unapproved abbreviations. Abbreviations that had more than one intended meaning and full names that were represented by more than one abbreviation were also noted. Sample Size Determination Approximately, 103,235 patients visit the outdoor pharmacy every month and using a 5% margin of error, 95% confidence interval and a 50% response distribution, 383 prescriptions were calculated as a representative sample for review (Raosoft. Inc, 2004, Seattle, WA). The proportions of prescriptions to be included from the OPD and the different specialty clinics were determined based on the out-patient and clinic attendance, and through expert opinion. The Survey Process To complement the prescription review process and obtain qualitative data, a survey was conducted. An interviewer administered questionnaire was developed and all 19 pharmacists who were attached to the outdoor pharmacy were invited for the survey. Demographic information and attitudes on abbreviations were assessed in the questionnaire. The English version of the questionnaire was validated by five academic pharmacists (not included as study participants) before conducting the survey. Each question was validated on its relevance to the objective, appropriateness of response options, clarity to the reader, whether testing what was intended by researcher, and if rewording was needed, using a five point ordinal scale. According to their comments, two questions were modified

3 The Pattern of Abbreviation Use in Prescriptions Current Drug Safety, 2014, Vol. 9, No. 1 3 Table 1. Comparison of Error-Prone Abbreviations Listed by Different Safety Organisations Error-Prone Abbreviation Intended Meaning ISMP JCAHO HAHK ACSQH µg Microgram ü ü ü mcg Microgram ü ü BID or bid Twice a day ü AD, AS, AU Right ear, left ear, each ear ü OD, OS, OU Right eye, left eye, each eye ü OW Once week ü p/f Per fortnight ü BT Bedtime ü ü cc Cubic centimeters ü ü D/C Discharge or discontinue ü ü e/ E Eye ü gtt or gutte Drops ü IJ Injection ü ü IN Intranasal ü ü IT Intrathecal ü HS or hs Half-strength at bedtime, hours of sleep ü ü IU** International units ü ü ü ü o.d. or OD Once daily ü ü ü OJ Orange juice ü ü Per os By mouth, orally ü Pulv Powder ü q.d. or QD** Every day ü ü ü ü q.h Every hour ü qhs Nightly at bedtime ü ü qn Nightly or at bedtime ü q.o.d. or QOD Every other day ü ü ü ü q1d Daily ü q6pm, etc. Every evening at 6 PM ü ü SC, SQ, sub q Subcutaneous ü ü SL Sublingual ü ss Sliding scale (insulin) or ½ (apothecary) ü ü SSRI Sliding scale regular insulin ü ü SSI Sliding scale insulin ü ü i/d, i/d One daily ü ü TIW or tiw Three times a week ü ü TID Three times a day ü U or u** Unit ü ü ü ü UD As directed ( ut dictum ) ü Ung Ointment ü M or m Morning ü N or n Night ü

4 4 Current Drug Safety, 2014, Vol. 9, No. 1 Samaranayake et al. (Table 1) contd.. Error-Prone Abbreviation Intended Meaning ISMP JCAHO HAHK ACSQH Occ or oc Eye ointment ü Mist Mixture ü Trailing zero - ü ü ü ü Lack of leading zero - ü ü ü ü Large doses without properly placed commas 100,000 units 1,000,000 units ü ü APAP acetaminophen ü ARA A vidarabine ü AZT zidovudine (Retrovir) ü CPZ compazine (prochlorperazine) ü DPT Demerol-Phenergan-Thorazine ü DTO Diluted tincture of opium, or deodorized tincture of opium ü HCl hydrochloric acid or hydrochloride ü HCT hydrocortisone ü HCTZ hydrochlorothiazide ü MgSO4 magnesium sulfate ü MTX methotrexate ü PCA procainamide ü PTU propylthiouracil ü T3 Tylenol with codeine No. 3 ü TAC triamcinolone ü TNK TNKase ü ZnSO4 zinc sulfate ü Nitro drip nitroglycerin infusion ü Norflox norfloxacin ü IV Vanc intravenous vancomycin ü x3d For three days ü ü > and < Greater than and less than ü ü / (slash mark) Separates two doses or indicates per ü At ü ü & And ü ü + Plus or and ü ü Hour ü ü. o r. zero, null sign ü MS Morphine sulphate or magnesium sulphate ü ü MSO 4 Morphine sulphate ü ü 6/24 Every six hours ü 1/7 For one a day ü ½ Half ü 10 6 One million ü ü, present ; ISMP, Institute of Safe Medication Practices; JCAHO, Joint Commission on Accreditation of Healthcare Organization; HAHK, Hospital Authority of Hong Kong; ACSQH, Australian Commission on Safety and Quality in Healthcare.

5 The Pattern of Abbreviation Use in Prescriptions Current Drug Safety, 2014, Vol. 9, No. 1 5 Table 2a. Reference List of Error-Prone Abbreviations Error-Prone Abbreviation Intended Meaning (Table 2a) contd... Error-Prone Abbreviation Intended Meaning µg Microgram Mcg Microgram BID or bid Twice a day AD, AS, AU Right ear, left ear, each ear OD, OS, OU Right eye, left eye, each eye OW Once week p/f Per fortnight BT Bedtime cc Cubic centimeters D/C Discharge or discontinue e/ E Eye gtt or gutte Drops IJ Injection IN Intranasal IT Intrathecal HS or hs Half-strength at bedtime, hours of sleep IU International units o.d. or OD Once daily OJ Orange juice Per os By mouth, orally Pulv Powder q.d. or QD Every day q.h Every hour qhs Nightly at bedtime qn Nightly or at bedtime q.o.d. or QOD Every other day q1d Daily q6pm, etc. Every evening at 6 PM SC, SQ, sub q Subcutaneous SL Sublingual ss Sliding scale (insulin) or ½ (apothecary) SSRI Sliding scale regular SSI Sliding scale insulin i/d, i/d One daily TIW or tiw Three times a week TID Three times a day U or u Unit UD As directed ( ut dictum ) Ung Ointment M or m Morning N or n Occ or oc Mist Trailing zero - Lack of leading zero - Large doses without properly placed commas APAP ARA A AZT CPZ DPT DTO HCl HCT HCTZ MgSO4 MTX PCA PTU Night Eye ointment Mixture 100,000 units 1,000,000 units acetaminophen vidarabine zidovudine (Retrovir) compazine (prochlorperazine) Demerol-Phenergan-Thorazine Diluted tincture of opium, or deodorized tincture of opium hydrochloric acid or hydrochloride hydrocortisone hydrochlorothiazide magnesium sulfate methotrexate procainamide propylthiouracil T3 Tylenol with codeine No. 3 TAC TNK ZnSO4 Nitro drip Norflox IV Vanc x3d triamcinolone TNKase zinc sulfate nitroglycerin infusion norfloxacin intravenous vancomycin For three days > and < Greater than and less than / (slash mark) Separates two doses or indicates & At And + Plus or and Hour. o r. zero, null sign MS MSO 4 Morphine sulphate or magnesium sulphate Morphine sulphate 6/24 Every six hours 1/7 For one a day ½ Half 10 6 One million

6 6 Current Drug Safety, 2014, Vol. 9, No. 1 Samaranayake et al. Table 2b. Standard Abbreviation List of the Hospital Authority of Hong Kong Approved Abbreviations for Drug Names Full Name Acetomenaphthone Vit K 4 Adenosine Triphosphate Adrenocorticotrophic Hormone Adsorbed Diphtheria & Tetanus Vaccine Adsorbed Diphtheria, Tetanus & Pertussis Vaccine Alpha Tocopheryl Acetate Alpha Tocopheryl Nicotinate Ascorbic Acid Bacillus Calmette Guerin Vaccine Calcium Carbonate Abbreviation ATP ACTH DT DTP Vit. E Vit. E Vit. C BCG Vaccine CaCO3 Calcium Chloride CaCl 2 Carmustine Cisplatin Cyanocobalamin Cytarabine Desmopressin Ergocalciferol, Calciferol Erythropoietin Etoposide Ferrous Sulphate Filgrastim Fluorouracil Glyceryl Trinitrate Hepatitis B Immune Globulin Isoniazid Lomustine BCNU CDDP Vit. B12 Ara-C DDAVP Vit. D2 EPO VP-16 FeSO4 G-CSF 5-FU GTN, TNG HBIG INAH CCNU Magnesium chloride MgCl 2 Magnesium Sulphate Measles/Mumps/Rubella Vaccine Mercaptopurine Methotrexate Molgramostim Phenoxymethylpencillin Phytomenadione Potassium Chloride Potassium Iodide Potassium Permanganate Propylthiouracil Prostaglandin E2 Pyridoxine Hydrochloride MgSO4 MMR Vaccine 6-MP MTX GM-CSF Pencillin V Vit. Kl KCl KI KMnO4 PTU PGE2 Vit. B6 (Table 2b) contd.. Riboflavine Sodium Bicarbonate Sodium chloride Teniposide Thiamine Approved Abbreviations for Drug Names Full Name Thyrotrophin-releasing hormone Thyroxine Liothyronine Sodium Zinc Oxide Balance Salt Solution Dihydrocodeine Tartrate Expectorant Stimulant Hydrocortisone 1% & Clioquinol 3% Multivitamin Vitamin B Complex Intradermal Intramuscular Intravenous Intraperitoneal Nasogastric Per oral Per rectum Per vagina Subcutaneous Sublingual Abbreviation Vit. B2 NaHCO3 NaCl VM-26 Vit. B1 TRH T4 T3 ZnO BSS DF118 MES H1V3 MV Vit.B Co Approved Abbreviations for Route of Administration Full Name I.D. I.M. I.V. I.P. Abbreviation N.G. P.O. P.R. P.V. S.C. S.L. and one question was added. The questionnaire was translated to Sinhalese language and the validity of the translation was assessed by a back translation method. Ethical approval was obtained from the Ethics Review Committees of the Faculty of Medical Sciences, University of Sri Jayewardenepura, Sri Lanka and the Colombo South Teaching Hospital, Sri Lanka. Informed consent was obtained from all participants before the survey. Statistical Analysis Data were analysed using SPSS 19.0 (IBM Corporation, Armonk, NY). The number of drug items prescribed in each phase was used as the denominator for calculating percentages in the prescription review study and the number of pharmacists that responded to the survey was used as the denominator when analysing survey results.

7 The Pattern of Abbreviation Use in Prescriptions Current Drug Safety, 2014, Vol. 9, No. 1 7 RESULTS 989 prescriptions that included 3370 drug items were reviewed in the study hospital. The mean (standard deviation) number of abbreviations per prescription was 5.9 (3.5). According to the reference list, the types of error-prone abbreviations used by prescribers and the rate of usage are shown in Table 3. µg (microgram), d (days/daily) and n (night) were the most commonly used error-prone abbreviations in the study hospital. Among the 103 types of abbreviations observed, 71 were unapproved (Table 3). Multiple abbreviations were used to indicate a single drug item/ instruction in 7 instances (Table 4). The abbreviation d was used to denote daily as well as days. Table 3. Error-Prone and Some Other Unapproved Abbreviations Used in the Study Hospital Abbreviation Error-Prone Abbreviations Percentage of Usage* d (days/daily) 23.5 µg (microgram) 17.4 n (night) 15.8 m (morning) sign 4.9 u (units) 1.9 cc (cubic centimeter) 0.2 OD (once a day) 0.2 mcg (microgram) 0.1 Some Frequently Used Unapproved Abbreviations pcm/pcm (paracetamol) 5.2 LA (local application) 2.2 MS (methyl salicylate) 1.9 o (oral) 1.5 syr/sy (syrup) 1.3 BCo (vitamin B complex) 0.8 DFS (diclofenac sodium) 0.7 HCT (hydorchlorothizide) 0.7 ISMN (isosorbide mononitrate) 0.7 tsp/ TSP (teaspoon) 0.6 EOD (every other day) 0.5 FA (folic acid) 0.5 α or 1α (1α colecalciferol) 0.3 ASP (Aspirin) 0.3 MSLA (methyl salicylate local application) 0.3 ISDN (isosorbide mononitrate) 0.2 *The number of drug items reviewed (N= 3370) was used as the denominator. Only 1/9 error-prone abbreviations used in the study hospital was cautioned by all four error-prone abbreviation lists. 2/9 error-prone abbreviations were cautioned by 3 of the lists and 4/9 were cautioned by 2 lists. All the pharmacists (N=19) who were invited, responded to the survey. Their demographic characteristics are shown in Table 5. Most pharmacists were years of age and most were females. The minimum qualification required to be recruited as a pharmacist in a Sri Lankan hospital is a Certificate of Proficiency awarded by the Ceylon Medical College Council of Sri Lanka. All pharmacists believed that using abbreviations will always (5.3%) or sometimes (94.7%) lead to medication errors. The reasons they believed that may lead to medication errors are shown in Fig. (1). Other reasons include, the ambiguity due to incomplete prescriptions, prescriptions not conforming to a uniform standard, different styles of hand-writing used by prescribers, and the use of non-standard abbreviations formed by different prescribers which would especially be unfamiliar to junior pharmacists. All pharmacists strongly agreed or agreed that confusing or misleading abbreviations should not be used in prescriptions and all acceptable abbreviations should be standardised. DISCUSSION In this study we aimed to study the use of error-prone abbreviations and other inappropriately used abbreviations in prescriptions. Approximately 69 error-prone abbreviations are used per every 100 drug items prescribed. Similar to our study, Dooley et al., also observed 76.9 error-prone abbreviations per every 100 patients and 8.4 error-prone abbreviations per every 100 prescriptions [6]. Further, abbreviations are used rather inconsistently in prescriptions. A large number abbreviations used are not standard or acceptable. Some drug items or instructions are identified by several abbreviations, and some abbreviations have more than one intended meaning. An example of an abbreviation that had more than one intended meaning from this study is the abbreviation d which was used to mean days as well as daily. It would not be surprising if a pharmacist interpreted 2d as two tablets daily when it was meant to read one tablet for 2 days. In such a case, the consequences to the patient, especially if the drug has a narrow therapeutic index would be significant. The use of inappropriate abbreviations may not only affect health care professionals but may cause problems to patients, particularly older patients when managing their numerous drugs [16]. Although technical abbreviations are not expected to be interpreted by patients, simple abbreviations such as the letter l used for liter could easily be misinterpreted as number one. Similarly, patients may misread number 1 as number 7, letter o as number 0, and letter z as number 2 [17]. Therefore we emphasise the importance of eliminating error-prone abbreviations and standardising the use of acceptable abbreviations as a vital necessity in hospitals that use handwritten prescriptions. Error-prone abbreviations were used in prescriptions of the study hospital but most were not identified in some of the error-prone abbreviation lists that already exist in other countries [3-5, 15]. In fact, most error-prone abbreviations

8 8 Current Drug Safety, 2014, Vol. 9, No. 1 Samaranayake et al. Table 4. Multiple Abbreviations Used to Denote the Same Drug Name/Instruction Drug Name or Instruction Abbreviation 1 % * Abbreviation 2 % * Abbreviation 3 %* Diclofenac sodium DF 0.1 DFS 0.7 Diclo Na 0.1 Folic acid FA 0.5 F.acid Glyceryle trinitrate GTN 0.7 TNT Paracetamol P.mol 0.03 PCM 5.2 Par 0.03 As needed PRN 0.1 SOS Thyroxine T T 0.1 Thy 0.03 Microgram µg 5.1 mcg Nocte n 4.7 Nt 0.1 Noc 0.03 Methyle salicylate MS 1.9 MSLA Vesper (evening) v 0.1 ves *The number of drug items observed (N=3370) was used as the denominator. Table 5. Demographic Characteristics of Survey Participants in the Study Hospital Characteristic N = 18 Age Groups, % Sex, % Men 27.8 Women 72.2 Higher Education Level *, % Certificate of Proficiency only 88.9 Diploma in Pharmacy 22.2 Degree in other discipline 16.7 Postgraduate 5.6 Years of Experience as a Pharmacist, % < 1 years years years 22.2 >10 years 55.6 *Percentages do not add up to 100% as some pharmacists had more than one qualification. Demographic data was missing in one participant. used in the study setting, were not included in the JCAHO and HAHK lists. Furthermore, many other potentially dangerous unapproved abbreviations used in prescriptions have not even been identified as error-prone. An example is the use of O to mean oral which could also be read as a zero. Pharmacists also pointed out that using O is too vague as they sometimes could not differentiate between the tablet and capsule forms. Sometimes the intended meaning of an abbreviation could vary by country. For example, MS is an error-prone abbreviation specified for morphine sulphate or magnesium sulphate in the ISMP and JCAHO lists, but is used to mean methyle salisylate in the study hospital. Hence it is clear that an error-prone abbreviation list intended for one setting is not always applicable to another. It would therefore be more prudent to develop an inhouse list of error-prone abbreviations that target inappropriate practices of the respective setting. Attitudes of pharmacists are an important source to determine difficulties associated with illegible prescriptions and ambiguous abbreviations. Therefore it is very important to involve practicing pharmacists in the development of error-prone abbreviation lists. Further, awareness programs should aim at informing prescribers of the difficulties created on their account. There are some limitations to this study. Firstly the study involved only one major government hospital in Sri Lanka and hence may not reflect the overall pattern of using errorprone and other unapproved abbreviations in the country. However, this need not affect our conclusion as similar findings were observed in other studies [6] and our previous unpublished audits in Hong Kong. Secondly, our prescription sample did not include in-ward prescriptions but as in-ward doctors participate in clinics, their pattern of using abbreviations was also reflected in our findings. The inappropriate abbreviations encountered in this study and the error-prone abbreviations specified by Do Not Use lists are in English or Latin. Abbreviations may differ depending on the language and country and hence the findings of this study may only apply to countries where prescriptions are written in English. The number of pharmacists who were attached to the outdoor pharmacy was limited. Therefore the sample of participants who were surveyed was small but included all the pharmacists in the out-patient pharmacy. A 100% response rate was achieved, but the responses may have been biased. The pharmacists were well aware of the aims and objectives of the study which may have influenced their attitudes on using unapproved abbreviations. Therefore, it must be borne in mind that the attitudes of this small group of pharmacists may not be generalisable. Care should be

9 The Pattern of Abbreviation Use in Prescriptions Current Drug Safety, 2014, Vol. 9, No. 1 9 Fig. (1). Reasons why abbreviations may lead to medication errors. The percentages do not add up to 100% because each pharmacist may have suggested more than one reason. taken when interpreting the survey results until supported by more larger and representative studies. We conclude that error-prone abbreviations are used in prescriptions and more than half the abbreviations used in prescriptions are unapproved. Some drugs or instructions are identified by multiple abbreviations, while some abbreviations have several interpretations. Unfortunately, the pattern of using unapproved abbreviations by prescribers is inconsistent and changes by hospital or country. Pharmacists who are involved in interpreting prescriptions agree that this erratic use of abbreviations may lead to medication errors. Therefore hospitals that use hand-written prescriptions should inform prescribers of this danger and develop in-house error-prone abbreviations list for their guidance. Further, the use of acceptable abbreviations should be standardised by introducing a standard abbreviations list. CONFLICT OF INTEREST The authors confirm that this article content has no conflict of interest. ACKNOWLEDGEMENTS BMY Cheung received support from the Faculty Research Fund, Li Ka Shing Faculty of Medicine, University of Hong Kong. N.R. Samaranayake holds a University Postgraduate Fellowship and a Postgraduate Scholarship from the University of Hong Kong. N.R. Samaranayake also holds the Wong Ching Yee Medical Scholarship for PATIENT CONSENT Declared none. REFERENCES [1] von Eschenbach AC. Eliminating error-prone notations in medical communications. Expert Opin Drug Saf 2007; 6(3): [2] Benjamin DM. Reducing medication errors and increasing patient safety: Case studies in Clinical Pharmacology. J Clin Pharmacol 2003; 43: 768. [3] Institute of Safe Medication Practices. ISMP's list of error-prone abbreviations, symbols and dose designations [Updated 2013 January 1: Cited 2013 July 1]; Available from: [4] The Joint Commission. Facts about the official Do Not Use list [Updated 2013 June 18: Cited 2013 July 1]; Available from: [5] Australian Commission on Safety and Quality in Healthcare. National terminology, abbreviations and symbols to be used in the prescribing and administering of medicines in Australian hospitals [Updated 2006 October; Cited 2013 July 1]; Available from: [6] Dooley MJ, Wiseman M, Gu G. Prevalence of error-prone abbreviations used in medication prescribing for hospitalised patients: Multi-hospital evaluation. Intern Med J 2012; 42(3): e [7] Miasso AI, Oliveira RCD, Silva AEBDC, et al. Prescription errors in Brazilian hospitals: a multi-centre exploratory survey. % Cad Saude Publica 2009; 25: [8] Myers JS, Gojraty S, Yang W, Linsky A, Airan-Javia S, Polomano RC. A randomized-controlled trial of computerized alerts to reduce unapproved medication abbreviation use. J Am Med Inform Assoc 2011; 18(1): [9] Whyte M. Computerised versus handwritten records. Pediatr Nurs 2005; 17(7): [10] Kuhn IF. Abbreviations and acronyms in healthcare: When shorter isn't sweeter. Pediatr Nurs 2007; 33(5): [11] Kushlan JA. Use and abuse of abbreviations in technical communication. J Child Neurol 1995; 10(1): 1-3. [12] Dunn EB, Wolfe JJ. Let go of Latin!. Vet Hum Toxicol 2001; 43(4): [13] Sheppard JE, Weidner LCE, Zakai S, Fountain-Polley S, Williams J. Ambiguous abbreviations: an audit of abbreviations in paediatric note keeping. Arch Dis Child 2008; 93(3): [14] NR Samaranayake, STD Cheung, W Chui, Cheung. B. Reducing the use of inappropriate abbreviations in prescriptions. Hong Kong Med J 2012; 18(Supplement 1): 45. [15] Medication Incident Reporting Program Bulletine. Update of Do Not Use list. Hong Kong Hospital Authority 2010 [cited 2010 August]; Available from: [16] D Fialová, G Onder. Medication errors in elderly people: contributing factors and future perspectives. Br J Clin Pharmacol 2009; 67(6): [17] Institute of Safe Medication Practices. Medical errors from misreading letters and numbers [Updated 2010 March; Cited 7 December 2013]; Available from: how=96#7 Received: October 17, 2013 Revised: December 11, 2013 Accepted: December 13, 2013 DISCLAIMER: The above article has been published in Epub (ahead of print) on the basis of the materials provided by the author. The Editorial Department reserves the right to make minor modifications for further improvement of the manuscript.