The growing problem of medication errors

Transcription

1 ANTIRETROVIRAL MEDICATION ERRORS IN PATIENTS WITH HIV INFECTION John J. Faragon, PharmD * ABSTRACT Medication errors are a growing phenomenon in the management of HIV because it entails the use of complex antiretroviral medications that are associated with numerous adverse side effects and are likely to cause drug-drug interactions. Pharmacists can help minimize HIV-related medication errors by analyzing the types of errors that are currently happening and developing effective strategies that can be used to prevent these errors from reoccurring. Providing examples that are specific to HIV treatment, this article focuses on the different types of medication errors, including wrong drugs, wrong doses, incorrect dosing frequency, and drug interaction problems. Issues that are addressed in this article include the use of abbreviations for HIV medications, soundalike drugs, prescriptions that are devoid of dietary restrictions, and findings indicating that 82% of HIV-related prescribing errors involve underdoses or overdoses. In discussing dosing frequency errors, the increasingly common use of once-daily dosing regimens is cited as an example. Patients taking once-daily antiretroviral agents who are not consistent in taking medications on the same schedule each day may be at risk for subtherapeutic drug levels toward the end of the dosing interval. Also *Clinical Pharmacist HIV Medicine, Albany Medical Center, Albany, New York. Address correspondence to: John J. Faragon, PharmD, Clinical Pharmacist HIV Medicine, Albany Medical Center, 43 New Scotland Avenue, MC-158, Albany, NY faragoj@mail.amc.edu. included in this article are strategies for identifying and preventing medication errors, such as the use of standardized, preprinted order sheets that list the common dosages of antiretroviral therapy, updated references including online databases, and healthcare provider-targeted education. (Adv Stud Pharm. 2006;3(5): ) The growing problem of medication errors has been described by numerous studies in various patient care settings. 1-4 However, the magnitude of these incidents particularly comes to light in a July 2006 report from the Institute of Medicine (IOM), which provides an overview of the medication errors associated with prescription, over-the-counter, and herbal therapies. The IOM estimates that at least 1.5 million preventable adverse drug effects from medication errors occur in the United States each year and result in significant costs to the healthcare system. 5 Although this report does not specifically evaluate errors associated with antiretroviral therapy, it does highlight a problem that continues to hinder care and is inherent to many complicated disease states that involve polypharmacy. HIV is an ideal example of a disease that is particularly prone to the risk of medication errors because it requires the use of complex and interaction-prone antiretroviral agents, in addition to other medications for the treatment of associated comorbidities. Patient care is further complicated when HIV infection is managed by healthcare providers who are not HIV specialists and, University of Tennessee Advanced Studies in Pharmacy 179

2 therefore, lack the necessary experience in this therapeutic area. The consequences of these issues are best exemplified in a recent retrospective study that identified 61 uncorrected errors among 77 admissions in which HIV-infected patients received antiretroviral therapy. The most common types of errors included the wrong amount or frequency of dosage, combining antiretroviral drugs with a contraindicated medication, administration of 2 or less antiretroviral agents, and unexplained delay in continuing antiretroviral therapy. 6 Pharmacists, with their growing involvement in clinical practice and HIV management, can have a major impact on minimizing HIV-related medication errors. To successfully reduce HIV-associated medication errors, pharmacists must be aware of the types of medication errors that are currently happening and develop effective strategies that can be used to prevent them. Also critical is the ability to identify the appropriateness of an antiretroviral regimen based on currently accepted practice guidelines. APPROPRIATE ANTIRETROVIRAL REGIMENS The most recent guidelines for the treatment of HIV infection recommend that newly diagnosed patients with HIV receive a non-nucleoside reverse transcriptase inhibitor (NNRTI) or a ritonavir-boosted protease inhibitor (PI), in combination with 2 nucleoside reverse transcriptase inhibitors (NRTIs). 7,8 Tables 1 and 2 summarize the initial treatment of HIV infection in adults, based on practice guidelines from the US Department of Health and Human Services and the International AIDS Society. Although published guidelines provide clear recommendations for initial regimens, they are, unfortunately, less clear on subsequent regimens in cases of therapeutic failure resulting from HIV resistance. Because patients with resistance to PIs, NNRTIs, or NRTIs are more challenging to manage, providers often must utilize HIV resistance testing to determine which medications will be effective in patients with documented resistance to these drugs. When a regimen is selected based on resistance testing, it may be atypical, and may involve the use of numerous medications from various classes of HIV medications. MEDICATION PRESCRIBING ERRORS IN HIV The potential consequences of medication prescribing errors in the setting of HIV treatment have been highlighted by formal studies and published case reports In one of the first studies to assess medication errors in HIV, investigators found that among HIV-infected patients receiving care at an academic teaching hospital, medication prescribing errors increased from 2% in 1996 to 12% in Of greater concern is that in 82% of prescribing errors detected, an underdose or overdose would have been administered to the patients if the incorrect orders Table 1. HHS Guidelines: Antiretroviral Regimens Recommended for Treatment of HIV-1 Infection in Antiretroviral-Naive Patients NNRTI-based Efavirenz + (lamivudine or emtricitabine) + (zidovudine or tenofovir DF) PI-based Atazanavir/ritonavir OR Fosamprenavir/ritonavir OR lopinavir/ritonavir (coformulation) + (lamivudine or emtricitabine) + zidovudine HHS = US Department of Health and Human Services; NNRTI = nonnucleoside reverse transcriptase inhibitor; PI = protease inhibitor. Adapted from Guidelines for the Use of Antiretroviral Agents in HIV-1- Infected Adults and Adolescents. US Department of Health and Human Services. Available at: AdultandAdolescentGL.pdf. Accessed October 11, Table 2. IAS-USA Panel: Recommended Components of Initial Antiretroviral Therapy Nucleoside (nucleotide) RTI Non-nucleoside RTI Tenofovir DF/emtricitabine (or lamivudine) OR zidovudine/lamivudine (or emtricitabine) OR abacavir/lamivudine (or emtricitbine) Efavirenz or nevirapine Ritonavir-boosted Ritonavir-boosted lopinavir protease inhibitors Ritonavir-boosted atazanavir Ritonavir-boosted fosamprenavir Ritonavir IAS-USA = International AIDS Society-USA; RTI = reverse transcriptase inhibitor. Reprinted with permission from Hammer SM, Saag MS, Schechter M, et al. Treatment for Adult HIV Infection: 2006 Recommendations of the International AIDS Society - USA Panel. JAMA. 2006;296: Vol. 3, No. 5 December 2006

3 Table 3. Types of Prescribing Errors Type of Error Wrong drug/formulation Wrong dose Wrong dosing frequency Drug interactions Missing information Example Soundalike or lookalike medication names Abbreviations leading to dispensing the wrong medication Wrong dosage formulation dispensed leading to incorrect dosage Overdosing Underdosing Failure to adjust for renal/hepatic impairment Failure to adjust for patient weight Wrong dosage formulation dispensed leading to overdosage or underdosage Three times a day vs every 8 hours Too often Too infrequent Drug-drug interactions Drug-food interactions Drug-herbal interactions Dosage strength missing Dosage frequency missing Dietary restrictions missing Reprinted with permission from Faragon JJ, Lesar TS. Update on prescribing errors with HAART. AIDS Read. 2003;13: Copyright 2003, The AIDS Reader, CMP Healthcare Media, Cliggott Publishing Group. All rights reserved. In addition to the similarities between brand and generic names, the use of abbreviations for HIV medication has complicated prescribing. Reports have described instances where zidovudine, often abbreviated as AZT, is mistaken for azathioprine For this reason, use of abbreviations, especially those associated with the antiretroviral therapies, should be avoided and prescriptions written with these abbreviations should not be filled until clarified. This recommendation is supported by recent guidelines released from the Joint Commission on Accreditation of Healthcare Organizations. 24 When writing prescriptions, prescribers should consider providing the generic and the brand name of the product, avoiding 3-letter chemical names as abbreviations, and specifying dosage formulations required for the patient. These precautions should minimize dispensing errors when prescriptions are being filled. WRONG DOSE As mentioned earlier, errors leading to potential overdoses or underdoses have been known to account for as much as 82% of highly active antiretroviral therapy (HAART)-related prescribing errors. 9 Wrong doses may occur when prescribers fail to adjust dosages were actually filled. Another common problem identified in the hospital setting is the lack of proper dietary restrictions being provided on prescriptions. One study at an academic teaching hospital found that dietary restrictions were missing or incorrect in 73% of orders. 11 The types of prescribing errors common in HIV care are listed in Table 3 and include wrong drug, incorrect drug formulation, wrong dose, incorrect dosing frequency, and drug interactions. WRONG DRUG The assigning of similar names to unrelated drugs often creates confusion and results in prescribing errors. As an example, the NNRTI nevirapine (Viramune; Boehringer Ingelheim Pharmaceuticals, Inc., Ridgefield, CT) has been mistaken for nelfinavir (Viracept; Pfizer, New York, NY) because the generic and brand names for these products are similar Table 4 includes common examples of HIV-related, potentially confusing drug names. Table 4. Soundalike/Lookalike Drugs in HAART azidothymidine lamivudine nevirapine ritonavir saquinavir Viramune (Boehringer Ingelheim Pharmaceuticals, Inc., Ridgefield, CT) Viread (Gilead Sciences, Foster City, CA) zidovudine Kaletra (Abbott Laboratories, Chicago, IL) Prezista (Tibotec, Mechelen, Belgium) azathioprine lamotrigine nelfinavir Retrovir (GlaxoSmithKline, Pittsburgh, PA) Sinequan (Pfizer, New York, NY) Viracept (Pfizer, New York, NY) Viramune or Viracept Zovirax (GlaxoSmithKline, Pittsburgh, PA) Keppra (UCB, Smyrna, GA) Prevacid (TAP Pharmaceuticals, Lake Forest, IL) Reprinted with permission from Faragon JJ, Lesar TS. Update on prescribing errors with HAART. AIDS Read. 2003;13: Copyright 2003, The AIDS Reader, CMP Healthcare Media, Cliggott Publishing Group. All rights reserved. University of Tennessee Advanced Studies in Pharmacy 181

4 of antiretroviral drugs or other associated agents based on patients weight and/or renal/hepatic impairment, failure to use appropriate dose titration schedules, or failure to adjust doses to manage drugdrug interactions. Table 5 lists common dosage adjustments for weight and renal and/or hepatic impairment. For patients prescribed an agent at a lower than therapeutic dose, there is obvious concern about the possibility of treatment failure and HIV resistance. Table 5. Antiretroviral Agents Requiring Reductions in Dosage Because of Weight or Renal Impairment didanosine weight/renal ClCr (ml/min) >60 <60 kg mg QD 250 mg QD mg QD 125 mg QD mg QD 125 mg QD < mg QD 125 mg QD HD 125 mg QD 125 mg QD emtricitabine renal ClCr (ml/min) mg QD mg Q48H mg Q72H < mg Q96H HD 200 mg Q96H after dialysis lamivudine renal ClCr (ml/min) mg BID or 300 mg QD mg QD mg first dose, then 100 mg QD mg first dose, then 50 mg QD <5 Consider 150 mg first dose, then 50 mg QD stavudine weight/renal ClCr (ml/min) Wt 60kg Wt <60kg >50 40 mg BID 30 mg BID mg BID 15 mg BID mg QD 15 mg QD HD 20 mg QD 15 mg QD tenofovir renal ClCr (ml/min) mg QD mg Q48H mg twice weekly HD 300 mg once weekly zidovudine renal ClCr (ml/min) < mg TID HD 100 mg TID zidovudine/lamivudine renal Separate into individual components, dose adjust as needed zidovudine/lamivudine/ abacavir renal Separate into individual components, dose adjust as needed abacavir/lamivudine renal Separate into individual components, dose adjust as needed tenofovir/emtricitabine renal ClCr (ml/min) 50 1 tablet daily tablet Q48H <30 Separate into individual components, dose adjust as needed BID = twice a day; Q48H = every 48 hours; Q72H = every 72 hours; Q96H = every 96 hours; QD = once a day; QID = 4 times a day ; TID = 3 times a day. Adapted with permission from Rodriguez RA, McNicholl IR. Dosing of antiretroviral drugs in renal insufficiency and hemodialysis. AIDS Education and Training Centers National Resource Center Web site. Available at: Accessed September 27, Vol. 3, No. 5 December 2006

5 Not including dietary restrictions on prescriptions can also adversely affect care because levels of antiretroviral agents, in addition to certain adverse effects, can be dependent on food and fluid intake. If, for example, didanosine enteric-coated capsules are taken by patients on a full stomach, the absorption of the drug could be markedly impaired, resulting in treatment failure or NRTI resistance. Table 6 includes common dietary restrictions for medications used in the treatment of HIV. Conversely, if patients were to receive a prescribed overdose of an antiretroviral agent, they would be at risk for potential toxicities including increased gastrointestinal adverse events, pancreatitis, hepatotoxicity, renal toxicity, and metabolic complications. Wrong dose errors may also occur when different formulations are introduced into the market. As an example, the recent reformulation of lopinavir/ritonavir (Kaletra; Abbott Laboratories, Chicago, IL) from soft gelatin capsules to tablets has resulted in errors at our academic medical center because the old soft gelatin capsule formulation was dosed at 3 capsules twice daily (providing 400 mg of lopinavir and 100 mg of ritonavir per dose) whereas the new tablet formulation is dosed at 2 tablets twice daily (also providing 400 mg of lopinavir and 100 mg of ritonavir per dose). When pharmacists converted orders from the old to the new formulation, some patients erroneously received 3 tablets twice daily instead of 2 tablets twice daily. When new formulations are introduced into the market, prescribers and pharmacists must be diligently educated to prevent incorrect doses from being dispensed to patients. INCORRECT FREQUENCY Prescribing HAART at an incorrect frequency represents a significant medication error. One classic example involves the prescribing of the protease inhibitor indinavir at 3 times daily instead of every 8 hours. In many hospitals, the time of administration for 3 times daily is not spaced out evenly across the day, so patients may receive 3 doses within an 18-hour period. However, if the prescription for indinavir is written for every 8 hours, patients will receive 3 evenly spaced doses within a 24-hour period. Studies have found incorrect dosing frequency to occur in as many as 40% of patients receiving PI therapy. 9,10 The increasingly common use of once-daily dosing regimens in HIV is also associated with frequency errors but frequency errors that patients are more likely to make. Individuals taking once-daily antiretroviral agents who are not consistent in taking medications on the same schedule each day may be at risk for subtherapeutic drug levels toward the end of the dosing interval, which may place them at risk for HIV resistance and virologic failure. Therefore, patients unaccustomed to taking their medications at the same time each day must be educated about the importance of keeping a strict medication Table 6. Dietary Restrictions with Antiretroviral Agents Class/Medication Nucleoside/nucleotide RTI abacavir didanosine emtricitabine lamivudine stavudine tenofovir zalcitabine zidovudine Non-nucleoside RTI delavirdine efavirenz nevirpaine Protease inhibitor atazanavir darunavir fosamprenavir indinavir lopinavir/ritonavir nelfinavir ritonavir saquinavir-hgc tipranavir Dietary Restriction Alcohol increases ABC levels 41%. Take on an empty stomach. Take on an empty stomach. Take with a meal or snack. Take on an empty stomach or light snack. If taking with ritonavir, may be taken with food. Drink 1.5 L of water daily. Take within 2 hours of a meal. RTI = reverse transcriptase inhibitor. Adapted with permission from Wolbach-Lowes J, Jed S, Johnson S, et al. A pharmacist s guide to antiretroviral medications for HIV-infected adults and adolescents. Mountain Plains AIDS Educations and Training Center. Available at: Accessed September 27, University of Tennessee Advanced Studies in Pharmacy 183

6 Table 7. Contraindicated Medications with Protease-Inhibitor Based Regimens amiodarone astemizole bepredil cisapride ergotamine derivatives esomeprazole (do not use with atazanavir) flecainide lansoprazole (do not use with atazanavir) lovastatin midazolam omeprazole (do not use with atazanavir) pimozide propanone quinidine rabeprazole (do not use with atazanavir) rifampin rifapentine simvastatin St. John s Wort terfenadine triazolam Adapted with permission from New York State Department of Health AIDS Institute. HIV clinical resource. Available at: Type=txt. Accessed September 27, Copyright , New York State Department of Health AIDS Institute s Clinical Guidelines Development Program. administration schedule. Nursing and pharmacy staff also need to be cognizant of the importance of administering once-daily regimens at the same time each day. With the current use of ritonavir-boosted PIs, patients, nurses, and pharmacists must be aware that the ritonavir component of the regimens must be given at the same time as the PI being boosted. For example, patients receiving a ritonavir-boosted atazanavir regimen should take atazanavir and ritonavir at the same time. Administering atazanavir and ritonavir at separate times defeats the rationale for boosting PIs and may result in subtherapeutic atazanavir levels. DRUG INTERACTIONS Drug interactions often complicate HIV care because NNRTIs and PIs are metabolized by the cytochrome P450 (CYP450) enzyme system and can inhibit or induce the activity of CYP450 enzymes. As a result, certain prescription, over-the-counter, and herbal therapies are contraindicated or may require dosage adjustments when used concurrently with HAART. 25,26 Table 7 lists medications that are contraindicated with the use of PIs. More extensive reviews of drug interactions can be found in Piscitelli et al and Back. 27,28 IDENTIFICATION AND PREVENTION OF MEDICATION PRESCRIBING ERRORS IN HIV For the hospital pharmacist, identification of prescribing errors involving HIV medications can be a difficult challenge because, in many instances, the medications that patients receive outside the hospital may be unavailable or difficult to obtain. However, strategies that may be used to prevent or minimize the occurrence of medication errors are described below and included in Table 8. Pharmacists can identify and prevent medication orders in the hospital setting by systematically screening inpatient and discharge orders, in addition to providing an HIV pharmacy admission note. 29 The use of standardized, preprinted order sheets that list the common dosages of antiretroviral therapy can also reduce Table 8. Prevention Strategies Provide brand and generic names on prescriptions to avoid confusion associated with order transcription or dispensing. Avoid and discourage the use of abbreviations. Update knowledge on HIV-related drugs and provide current references to healthcare providers. Provide education to pharmacy and nursing staff regularly. Review medication administration record regularly, consider providing a pharmacy admission note, and consider use of preprinted order forms when ordering antiretrovirals. Encourage patients to fill prescriptions at 1 pharmacy. Use charts of antiretrovirals that include medication photographs and dosing to help identify regimens. Share information with the medical staff when frequent errors are occurring. Reprinted with permission from Faragon JJ, Lesar TS. Update on prescribing errors with HAART. AIDS Read. 2003;13: Copyright 2003, The AIDS Reader, CMP Healthcare Media, Cliggott Publishing Group. All rights reserved. 184 Vol. 3, No. 5 December 2006

7 medication errors. 30 To prevent confusion in filling orders, pharmacists should encourage prescribers, including training house staff, to provide generic and brand names on prescriptions, in addition to avoiding the use of abbreviations. Also, agencies responsible for naming new medications should make a concerted effort to avoid selecting names that are similar to drugs currently available on the market. In order for healthcare professionals to provide accurate and quality care to HIV-infected patients, access to updated references is essential. Because new information is constantly being presented at major HIV conferences, references must include online databases, which are likely to contain more recent information than printed resources. Pharmacy computer programs, particularly those that include drug-interaction detection programs, should be updated on a regular basis. Increased use of technology, including physician order entry, bar coding of medications, and Personal Digital Assistants, may also reduce the frequency of prescribing errors in medicine. 31,32 Patients also play a pivotal role in preventing errors from occurring; therefore, they should be encouraged to maintain a current list of their medications and use only 1 pharmacy when filling their prescriptions. Charts containing pictures of HIV medications can be used in inpatient settings to help identify patients regimens, especially when patients are unable to remember the names of their drugs. Finally, education for the healthcare provider is the mainstay of successful error detection and prevention in HIV care. Because new HIV information is constantly being introduced, providers must be educated about recent US Food and Drug Administration labeling changes, new medications, and new antiretroviral regimens being studied. Local training organizations, such as the AIDS Education and Training Centers, play a crucial role in providing education and updates to healthcare professionals working with HIV-infected patients. CONCLUSIONS Unfortunately, medication errors in HIV are a common problem. Pharmacists, however, can play a significant role in preventing their occurrence by recognizing appropriate HIV combinations, helping to identify potential drug-drug interactions, and ensuring that prescriptions are written with accurate dosing instructions. Consistent, ongoing training of pharmacists involved in HIV care is crucial in preventing medication errors. REFERENCES 1. Flynn EA, Barker KN, Pepper GA, et al. Comparison of methods for detecting medication errors in 36 hospitals and skilled-nursing facilities. Am J Health Syst Pharm. 2002;59: Barker KN, Flynn EA, Pepper GA, et al. Medication errors observed in 36 health care facilities. Arch Intern Med. 2002;162: Lesar TS, Lomaestro BM, Pohl H. Medication prescribing errors in a teaching hospital: a nine-year experience. Arch Intern Med. 1997;157: Lesar TS, Briceland LL, Delcoure K. Medication prescribing errors in a teaching hospital. JAMA. 1990;263: Anonymous. Preventing medication errors: Quality Chasm Series. Institue of Medicine Report. July Available at: 43.aspx. Accessed September 1, Rastegar DA, Knight AM, Monolakis JS. Antiretroviral medication errors among hospitalized patients with HIV. Clin Infect Dis. 2006;43: Anonymous. Guidelines for the use of antiretroviral agents in HIV-1 infected adults and adolescents. May 4, Available at: AdultandAdolescentGL_PDA.pdf. Accessed October 10, Hammer SM, Saag MS, Schechter M, et al. Treatment for adult HIV infection: 2006 recommendations of the International AIDS Society USA Panel. JAMA. 2006;296: Ungvarski PJ, Rottner JE. Errors in prescribing HIV-1 protease inhibitors. J Assoc Nurses AIDS Care. 1997;8: Purdy BD, Raymond AM, Lesar TS. Antiretroviral prescribing errors in hospitalized patients. Ann Pharmacother. 2000;34: Edelstein H, Wilson M. Antiretroviral medication errors were universal in hospitalized HIV-seropositive patients at a teaching hospital. J Acquir Immune Defic Syndr. 2001;28: Kakuda TN, Acosta EP, Fletcher CV. Potential confusion with antiretroviral drugs. Am J Health-Syst Pharm. 1998;55: Johnson JT, Dunn EB, Wolfe JJ. Two antiretroviral drugs likely to be confused. Am J Health-Syst Pharm. 1998;55: Max B, Mourikes N. Confusion of nelfinavir and nevirapine. N Engl J Med. 1998;338: Raffalli J, Nowakowski J, Wormser GP. Vira something: a taste of the wrong medicine. Lancet. 1997;350: Cohen M, Davis N. AZT is a dangerous abbreviation. Am Pharm. 1992;32: Landis SJ. Azathioprine or azidothymidine. CMAJ. 1990;143: Ambrosini MT, Mandler HD, Wood CA. AZT: zidovudine or azathioprine? Lancet. 1992;339: DeLorenze GN, Follansbee SF, Nguyen DP, et al. Medication errors in the care of HIV/AIDS patients: electronic surveillance, confirmation, and adverse events. Med Care. 2005;43(suppl):III University of Tennessee Advanced Studies in Pharmacy 185

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