Patient Safety Advisory Reprinted from the PA-PSRS Patient Safety Advisory—Vol. 1, No.4 (December 2004) Produced by ECRI & ISMP under contract to the Pennsylvania Patient Safety Authority Drug Name Suffix Confusion is a Common Source of Errors M edications with delayed- or extended-release formulations can play a vital role in improving adherence to drug therapy. These unique dosage In an analysis of 402 prescribing errors, Lesar3 found that the most common type of error was fail- formulations avoid the need for multiple daily doses ure to specify the controlled-release formulation of a medication due to their delayed or sustained (280 cases, 69.7%). The Institute for Safe Medica- delivery of a total daily dose steadily throughout the tion Practices (ISMP) has received reports of confu- day. This is convenient for patients, may reduce sion between Abbott’s DEPAKOTE ER (divalproex certain side effects, and, on occasion, even allows sodium extended release) and DEPAKOTE use for different indications. However, the nomen- (divalproex sodium delayed release).4 Additional clature used for long- examples include GLUCOTROL and GLUCOTROL XL as well as GLUCOPHAGE and GLUCOPHAGE The nomenclature acting confusing, forms er- often dosage and is XR. used to distinguish rors may occur when the different drug for- same drug has several The most common examples of this type of error reported to PA-PSRS include mix-ups between mulations often fails oral dosage forms with products such as: different release rates. to provide “cues” regarding proper use The practice of adding • ADDERALL and ADDERALL XR of a dosage form. “suffixes” or “modifiers” • EFFEXOR and EFFEXOR XR (e.g., Depakote ER or • VICODIN and VICODIN ES Cardizem CD) to medica- tion names is used by manufacturers to maintain Additional examples include: brand awareness while signifying that the formula- tion is different from the immediate-release version • AUGMENTIN and AUGMENTIN XR of the product. However, there is no standardization • CARDIZEM and CARDIZEM CD of the terms for the many different kinds of long- • CIPRO and CIPRO XR acting formulations. As a result, there are many in- • DEPAKOTE and DEPAKOTE ER consistencies, allowing different suffixes to be used • DETROL and DETROL LA for an identical formulation by two different manu- • LOPRESSOR and LOPRESSOR XL (the XL facturers or even similar suffixes for dissimilar for- formulation is Toprol XL) mulations. In short, the nomenclature used for these • RYTHMOL and RYTHMOL SR formulations often fails to provide appropriate “cues” regarding proper use of a dosage form.1 • SENOKOT and SENOKOT S • SINEMENT and SINEMENT CR In addition to lack of standards, another problem is • verapamil and verapamil SR that health professionals have been known to com- municate drug names that have suffixes, but omit The confusion multiplies when there are two or the suffix. This occasionally results in patients get- more “extended” release formulations for the same ting the immediate-release version and thus, an en- products, which are not therapeutically equivalent tire day’s dose at one time, sometimes with adverse or “substitutable.” Some products have numerous effects. Practitioners have also been known to in- This article is reprinted from the PA-PSRS Patient Safety Advisory, Vol. 1, No. clude suffixes that do not exist for the specified 4—December 2004. The Advisory is a publication of the Pennsylvania Patient product.2 Additional contributing factors reported to Safety Authority, produced by ECRI & ISMP under contract to the Authority as part of the Pennsylvania Patient Safety Reporting System (PA-PSRS). PA-PSRS include similar packaging, overlapping dosages, and storage of the products next to each Copyright 2004 by the Patient Safety Authority. This publication may be re- other. These factors combine to allow confusion, printed and distributed without restriction, provided it is printed or distributed in inefficiencies, and medication errors at various its entirety and without alteration. Individual articles may be reprinted in their entirety and without alteration provided the source is clearly attributed. stages in the medication use system. To see other articles or issues of the Advisory, visit our web site at www.psa.state.pa.us. Click on “Advisories” in the left-hand menu bar. ©2004 Pennsylvania Patient Safety Authority Page 1 Reprinted from the PA-PSRS Patient Safety Advisory—Vol. 1, No. 4 (December 2004) Drug Name Suffix Confusion is a Common Source of Errors suffixes to differentiate formulations of the same staff about the differences where a high drug. For example, suffixes for various diltiazem risk of error exists or when a mix-up might products include SR, CD, XR, XT, and LA. ISMP be very serious. also has received reports where pharmacists dispensed METADATE ER instead of META- • Designing computer mnemonics to sepa- DATE CD. Similarly, ISMP has received a report rate the different formulations on computer where a prescription for METADATE CD 20 mg screens used during order entry. was dispensed as METADATE ER 20 mg. The pharmacists involved in these errors weren’t • Storing similarly named drugs separately aware that the METADATE CD product ex- and using auxiliary labels to differentiate isted.5 PA-PSRS has received reports noting the products in medication storage areas. confusion between medications such as the once-a-day formulation WELLBUTRIN XL • Verifying new prescriptions for any of these (bupropion extended-release) and WELL- medications where prescriber confusion BUTRIN SR (buproprion sustained-release), among suffixes has been reported. which is indicated for twice-daily dosing. Well- butrin mix-ups are especially likely since both • When communicating orders orally, using the SR and XL formulations are available in 150 the full words “extended release” or mg tablet strengths, and it’s not unusual for the “sustained release,” not abbreviations, es- SR formulation to be prescribed once daily. pecially for those medications that are available as an immediate release formula- Drug name suffixes are confusing enough with- tion. out coining them on our own. One report to ISMP involved a physician assistant that wrote a • Involving patients also may help. When prescription for a patient, which was misread by prescribing and dispensing one of these both the pharmacist and technician as VICODIN medications, practitioners may want to in- ES (hydrocodone 7.5 mg/ acetaminophen 750 form patients of the potential for confusion mg). However, on closer inspection, the suffix between the various formulations and suf- looked more like RS. The pharmacist called the fixes. physician assistant and learned that he had used “RS” to mean “regular strength.” VICODIN Notes (hydrocodone 5 mg/acetaminophen 500 mg) 1. Cohen MR, ed. Medication Errors. Causes, Preventions was then dispensed.6 and Risk Management. Sudbury (MA): Jones and Bartlett Publishers; 2000. In order to improve the landscape when suffixes 2. ISMP Medication Safety Alert! Community Phar- macy/Ambulatory Edition. 15 Jul 2004;(9)14. are used and reduce the risk of errors, nomen- 3. Lesar TS. Medication errors related to dosage formula- clature standards would help to diminish confu- tion issues. Medscape Pharmacists 2001. Available on sion between various formulations of the same Internet: drug.7 Standard suffixes or descriptive phrases http://www.medscape.com/viewarticle/408579_print might be incorporated directly into the drug 4. ISMP Medication Safety Alert! 7 Feb 2001;(6)3. name, or a unique brand name might be needed 5. ISMP Medication Safety Alert!. 28 Nov 2001;(6)24. to designate a different formulation property, as 6. ISMP Medication Safety Alert! [online]. 15 Nov was done with NEORAL (cyclosporine modified) 2004;(9)14. 7. Cohen MR. Medication error reports. Hosp Pharm. and SANDIMMUNE (cyclosporine). FDA is 1990;25:747-8. aware of these problems and will be examining ways to improve trademark nomenclature. Being mindful of the potential for this type of confusion when prescribing, storing, dispensing, and administrating such medications is just the first step in prevention. Other preventive strate- gies to consider include: • Selectively building flags into computer sys- tems and marking drug containers to warn Page 2 ©2004 Pennsylvania Patient Safety Authority Reprinted from the PA-PSRS Patient Safety Advisory—Vol. 1, No.4 (December 2004) An Independent Agency of the Commonwealth of Pennsylvania The Patient Safety Authority is an independent state agency created by Act 13 of 2002, the Medical Care Availability and Reduction of Error (“Mcare”) Act. Consistent with Act 13, ECRI, as contractor for the PA-PSRS program, is issuing this newsletter to advise medical facilities of immediate changes that can be instituted to reduce serious events and incidents. For more information about the PA- PSRS program or the Patient Safety Authority, see the Authority’s website at www.psa.state.pa.us. ECRI is an independent, nonprofit health services research agency dedicated to improving the safety, efficacy and cost-effectiveness of healthcare. ECRI’s focus is healthcare technology, healthcare risk and quality management and healthcare environmental management. ECRI provides information services and technical assistance to more than 5,000 hospitals, healthcare organizations, ministries of health, government and planning agencies, and other organizations worldwide. The Institute for Safe Medication Practices (ISMP) is an independent, nonprofit organization dedicated solely to medication error prevention and safe medication use. ISMP provides recommendations for the safe use of medications to the healthcare community including healthcare professionals, government agencies, accrediting organizations, and consumers. ISMP's efforts are built on a non-punitive approach and systems-based solutions. ©2004 Pennsylvania Patient Safety Authority Page 3