he English language uses theLatin alphabet with 26 lettersand a numeric system with 10numerals. These alphanumeric

symbols (letters and numerals) workwell most of the time to communicateinformation. However, problems mayarise duringwritten or electronic com-munication because of similarities inappearance of the alphanumeric sym-bols we use. For example, the lowercase letter l looks exactly like thenumeral 1. The upper case letter Olooks like the numeral 0. Since manyof the symbols share similar, or evenidentical, physical characteristics, dif-ferentiation often poses a challenge.Table 1 lists examples of commonlyconfused alphanumeric symbols.

HHaannddwwrriitttteenn iinnffoorrmmaattiioonnMistaken letters and numerals play alarge part in errors when readinghandwritten drug names and doses.Cursive writing is most susceptible toillegibility and carries the greatest vul-nerability to error, as the various sym-bols often lack distinctiveness.1 A fewexamples of misinterpreted alphanu-

meric symbols that happened whenreading handwritten medicationorders follow.2

LLoowweerr ccaassee ll llooookkss lliikkee nnuummeerraall 11. Anurse misread an order for 2 mg ofAAMMAARRYYLL (glimepiride) as 12 mg(Figure 1).3 The lower case l at theend of the drug name, along withinsufficient space between the lastletter of the drug name and the dose,led the nurse to misread the dose as12 mg. The pharmacist processed theorder correctly as 2 mg, and the errorwas detected when the nurse calledto question why only 2 mg was dis-pensed. Similar dosing errors haveoccurred with other drugs with namesthat end in the letter l (see Figure 2for another example).4,5

LLoowweerr ccaassee ll llooookkss lliikkee uuppppeerr ccaassee II.While reviewing an order for a newlyadmitted patient, a pharmacist readIIOODDIINNEE in the space for allergies.Another pharmacist thought the aller-gy listed was LLOODDIINNEE (etodolac).The pharmacist contacted the

To prevent confusion with alphanum-eric symbols, consider the following:

Use lower case letters.Whilethere are several handwritten lowercase letters that are difficult to distin-guish (see Table 1), lower case lettersin general offer more differentiationthan upper case letters.

Use mixed case letters. Mixedcase letters (as with tall man lettering)also provide better distinction amongletters than using all upper case or alllower case letters.

Use block printing. Encourage pre-scribers to use block printing instead ofcursive writing for handwritten orders.

Use lightly lined forms. Lines onorder forms should be lightly shaded,making them visible to prescribers, yetstill light enough to prevent interfer-ence with written letters or numerals.

Use symbolic differentiation.Symbolic differentiation is another wayto distinctively convey a symbols mean-ing.1 For example, in Europe its com-mon to see a zero written with a slashthrough it () to differentiate it from theletter O. The numeral 7 and the letter Zcan be written with a bar (7 or Z) to pre-vent confusion with numerals 1 and 2.

Put a space between the drugname and dose. Allow adequatespace between the drug name and thedose to prevent misreading the dose.

Determine if the drug and dosemake sense. When reading an order,determine if the dose is within a recom-mended range and strength prescribed.If not, follow-up with the prescriber maybe necessary. In the case of medicationorders, context may help raise a red flagif the order has been misread.

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NurseAdvise-ERRISMP Medication Safety Alert!

Educating the healthcare community about safe medication practices June 2010 Volume 8 Issue 6

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Table 1. Examples of letters and numerals commonly confusedLower case letter l and upper case letter I Upper case letter E and upper case letter FLower case letter l and numeral 1 Upper case letter Z and numeral 2Lower case letter o and numeral 0 Upper case letter O and numeral 0Lower case letter g and lower case letter q Upper case letter B and numeral 8Lower case letter m and lower case letter n Upper case letter D and numeral 0Lower case letter y and lower case letter z Upper case letter S and numeral 5Lower case letter c and lower case letter e Upper case letter S and numeral 8Lower case cursive letter l and lower case cursive letter b Upper case letter Z and numeral 7Lower case cursive letter i and lower case cursive letter e Upper case letter T and numeral 7Lower case cursive letter a and lower case cursive letter o Numeral 5 and numeral 8Upper case letter T and upper case letter I Numeral 5 and numeral 3Upper case letter D and upper case letter O Numeral 7 and numeral 1

Figure 1. A 2 mg dose of Amaryl misread as 12 mg. Figure 2. Sildenafil 25 mg dose misread as 125 mg.4

Misidentification of alphanumeric symbols in both hand-written and computer-generated information

continued on page 2AAllpphhaannuummeerriicc

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NurseAdvise-ERRAAllpphhaannuummeerriicc continued from page 1 patients physician who identifiedLodine as the actual allergy.2 Thepatient was not harmed, but failureto document the correct allergycould have risked serious harm.

EElleeccttrroonniicc iinnffoorrmmaattiioonnElectronic medical records, medica-tion administration records, and com-puterized prescriber order entry canhelp overcome many of the problemsencountered with handwritten infor-mation. Fortunately, use of such tech-nology is growing. However, eventyped or computer generated physi-cian orders may not prevent confu-sion among certain alphanumericsymbols. For example, even a clearlytyped prescription for 25 mcg ofLLEEVVOOXXYYLL (levothyroxine) could bemisread as 125 mcg if it appears with-out proper spacing as Levoxyl25 mcg,especially since both strengths areavailable for this medication.

Information that contains bothnumerals and letters including anemail address or medication orderisparticularly prone to errors. Whilecontext can sometimes enhance sym-bol recognition, it can also detractfrom recognition. For example, if yousaw a Z, I, or O amid an array ofnumerals, you could easily mistake the

symbols as the numbers 2, 1, or 0.Additionally, word recognition soft-ware often has difficulty distinguish-ing L and I, Z and 2, and other look-alike symbols.

Research conducted by Bell Labora-tories found that some symbols aremore vulnerable than others tomisidentification.1 In the study, thesymbols l and 1, O and 0, Z and 2,and 1 and 7 accounted for morethan 50% of the errors caused bysymbol misidentification.

There are various ways to help copewith the inadequacies of alphanu-meric symbols that are prone toconfusion. To prevent confusionwith alphanumeric symbols, con-sider the recommendations listed inthe checkitout! column.RReeffeerreenncceess:: 11)) Nierenberg GI. Do it right the first time. New York:John Wiley and Sons 1996:154-162.22)) ISMP. Misidentification of alphanumeric symbols.ISMP Medication Safety Alert! Acute Care Edition2000;5(1):1. 33)) ISMP. Misidentification of alphanumeric charac-ters. ISMP Medication Safety Alert! Community/Ambu-latory Care Edition 2003;2(1):3. 44)) Pennsylvania Patient Safety Authority. What the lis the dose? PA PSRS Pat Saf Advis 2006;3(3):19- 20. 55)) ISMP. Tricks but no treats: Illusions and medicationerrors. ISMP Medication Safety Alert! Acute CareEdition 2002;7(22):1-2.

Free customized medication safety alerts for consumers and caregivers. Details at: www.consumermedsafety.org.

Patient education required.A diabetic patient was hospital-

ized with a sudden loss of control ofher blood glucose. The patient hadrecently started using a NOVOLOGMIX 70/30 FLEXPEN (insulin aspartprotamine suspension and insulinaspart injection, [rDNA origin]). Whenspeaking with the patient, a diabeteseducator discovered that the patientdid not know how to use the pen cor-rectly despite having read the manu-facturers directions. The patient wasable to measure her dose accuratelybut she was not pushing down on thebutton/plunger, nor was she holdingthe pen in place (with the needle inthe injection site) for at least 6 seconds.Once the diabetes educator workedwith the patient to correct her injec-tion technique, the patient requiredless insulin to control her blood sugar.Patients who will be using a new typeof insulin pen require direct educationby healthcare providersencouragingthe patient to read the literature thataccompanies the pen should be usedto reinforce the healthcare providerseducation, but should not be the solemeans of providing it. Dont assumepatients who are discharged withorders to use an insulin pen knowhow to correctly use it. Have thepatient demonstrate appropriate useof the pen prior to discharge.

Total amount may be mis-read. A 100 mg/mL unit dose

cup of levetiracetam (an anti-seizuremedication) from VistaPharm containsa total of 500 mg in the 5 mL cup. How-ever, the mg/mL dose could be misun-derstood as the total dose in the cup

because the5 mL volumein the cup islisted on thelabel in anarea far re-moved from

the concentration. If five cups were mis-takenly given to a patient for a 500 mgdose, the patient would actually receive

safetywires

continued on page 3 safetywires

Special solutions are used for organperfusion, flushing, and cold storageof harvested organs prior to kidney,liver, and pancreastransplantation.These solutions,such as VVIIAASS--PPAANN and SSPPSS--11,contain extremelyhigh amounts ofpotassium, and areavailable in plasticbags that resembleIV infusion con-tainers (Figure 1).

In 2005 (Organ storage solution.ISMP Medication Safety Alert! June30, 2005) a pharmacist reported thata plastic liter bag of ViaSpan cold

storage solution was among variousproducts and IV bags returned forcredit to the hospital pharmacy.

Upon investiga-tion, the pharma-cist learned thatan organ procure-ment team hadjust visited thehospital to retrieveorgans. The teamdid not use allthe ViaSpan theyhad brought withthem. Somehow,

one bag had been inadvertentlyplaced in the pharmacy return binbecause it looked so much like an IVsolution bag.

Confusion between organ preservation solutions and IV containers

Figure 1. ViaSpan cold storage solution is fatal ifgiven IV (photo from Teva Web site).

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NurseAdvise-ERR

2,500 mg. The pediatric hospital phar-macist who reported this feels thatthe risk of a dose miscalculation ishigh, and we agree. Weve askedVistaPharm to revise the label.

Report bad advertising. Incase you havent heard, the FDAs

Division of Drug, Marketing, Advertising,and Communications (DDMAC) launch-ed its Bad Ad Program (www.fda.gov/badad) on May 11 with a dual purpose:1) to educate healthcare providersabout the steps FDA is taking to pre-vent misleading or inaccurate promo-tion of prescription drugs by drug com-panies; and 2) to request help fromhealthcare providers in identifying andreporting these activities. Pharmaceuti-cal companies spend up to three timesmore on advertising directly to health-care professionals than on advertisingto consumers. Such detailing occursprimarily in medical offices, hospitals,and at medical meetings and symposia.Informative and responsible promotion-al efforts can provide professionals withvaluable information about the latestdrug therapies. However, informationthat may affect prescribing decisionsmust be accurate and balanced. FDA isasking practitioners to report misleadingprescription drug promotion by calling(877) RX-DDMAC (877-793-3622) oremailing a summary of the incident toBadAd@fda.gov. If you are unsure aboutwhat constitutes misleading promotion,please call DDMAC at (301) 796-1200.

safetywires contd from page 2

IISSMMPP MMeeddiiccaattiioonn SSaaffeettyy AAlleerrtt!! NNuurrsseeAAddvviissee--EERRRR (ISSN 1550-6304) 22001100IInnssttiittuuttee ffoorr SSaaffee MMeeddiiccaattiioonn PPrraaccttiicceess((IISSMMPP)).. Permission is granted to subscribersto reproduce material for internal newslet-ters or communications. Other reproductionis prohibited without written permission.Unless noted, published errors were receivedthrough the ISMP Medication ErrorsReporting Program. EEddiittoorrss:: Judy Smetzer,RN, BSN, FISMP; Ann Shastay, RN, MSN,AOCN; Michael R. Cohen, RPh, MS, ScD;Russell Jenkins, MD. IISSMMPP,, 220000 LLaakkeessiiddeeDDrriivvee,, SSuuiittee 220000,, HHoorrsshhaamm,, PPAA 1199004444--22332211..Tel.: 215-947-7797; Fax: 215-914-1492;EMAIL: nursing@ismp.org.RReeppoorrtt mmeeddiiccaattiioonn eerrrroorrss ttoo IISSMMPP aatt

11--880000--FFAAIILL--SSAAFF((EE))..

SSoolluuttiioonnss continued from page 2 Recently, the California Departmentof Public Health received com-plaints about this product andpassed them on to the CaliforniaHospital Association Patient SafetyOrganization (CHA PSO). As aresult, the CHA PSO sent Californiahospitals an alert about these solu-tions entering hospitals throughmaterials management and bypass-ing the pharmacy. Inadvertent IVadministration of the solution wouldalmost certainly cause cardiac arrestdue to the high potassium content(about 125 mEq/L). The bag has aport that will accommodate IV tubingwhich could allow this to happen.

We have contacted Teva, the manu-facturer of ViaSpan, to ask the com-pany to improve product safety withenhanced label warnings. The labelon the bag warns that the solution isnot for direct injection, and that thepotassium content is high. However,the warning, printed in small black

letters, is easily lost in the otherinformation listed on the front label.We have also contacted theAssociation of Organ ProcurementOrganizations to enlist its help ingetting the word out to transplantstaff to never leave unused cold stor-age solution containers on locationafter organ harvest.

Please alert operating room staff atyour hospital regarding this possiblerisk. While we are not aware of anactual incident, a harmful error ispossible in any hospital where organsmight be harvested. For hospitalswhere these products are routinelystored, be sure to sequester the solu-tions away from IV solutions. Askpharmacy or operating room staff toapply auxiliary warning labels to theouterwrap that reflect the potentialdanger of IV administration, notingthat this concentrated electrolytesolution is to be used only for storageor flushing of harvested organs.

Special Announcements

ISMP Webinar: Join us on June 30 for a special webinar that taps into the heart ofISMP staffs expertise in medication safety, Risks encountered during ISMP hospi-tal safety assessments. ISMPs interdisciplinary consulting team has been invitedinto hundreds of hospitals across North America to assess risk and provide individuallytailored support for medication safety improvements. Join the consulting team as theydiscuss common but serious system-based risks encountered in many of these hospi-tals and share innovative and proven best practice recommendations that organiza-tions can implement. To register, please visit: www.ismp.org/educational/webinars.asp.

Nursing Leadership Webinars. June 23: The Patient Safety Plan: Design, Implement and GrowLearn about creating and sustaining a culture of safety, which may be one of the bestways to deal with increasing regulatory demands, transparency, and declining reim-bursements.

August 26: Health Information Exchange for Promoting Patient SafetyLearn how one hospital system is meeting the challenge of providing a connected careexperience for patients who have clinical data in disparate ambulatory and acute-careelectronic medical records.

Free medication safety videos. The latest medication error-related FDA PatientSafety News videos (created in coop-eration with ISMP) are available forfree viewing or downloading at:www.ismp.org/Tools/fdavideos.asp.Just a few of the videos are listed inthe table to the right, with manymore available on our Web site!

May 2010 Avoiding Maalox Mix-upsMarch 2010 Medical Errors from Misreading Letters

and NumbersFebruary 2010 Mix-ups between Kapidex and CasodexJanuary 2010 Never Use Parenteral Syringes for Oral

Medications

Free customized medication safety alerts for consumers and caregivers. Details at: www.consumermedsafety.org.