The Medical Toxicologist and Medication Errors

Charles A. McKay MD*

Director, Medical Toxicology Fellowship,

Associate Professor of Emergency Medicine,

University of Connecticut School of Medicine

Associate Medical Director, Connecticut Poison Control Center

Chair, Practice Committee, American College of Medical Toxicology


Jason Vena MD

Medical Toxicology Fellow,
University of Connecticut School of Medicine

Int J Med Toxicol 2004; 7(1): 1


Errors in medical practice occur on a daily basis in all practices and institutions. Often, these errors are inconsequential, representing clinically insignificant errors in diagnosis and treatment. At times, potentially significant errors are detected and corrected. Unfortunately, some errors are not detected and/or corrected, and patients are harmed. Regardless of whether a patient is harmed or not, these errors provide an opportunity for us as practitioners to improve our systems of delivering care. The highly touted, yet often criticized, Institute of Medicine report entitled "To Err is Human: Building a Safer Health System" concludes that 44,000-98,000 Americans die yearly as a result of healthcare errors (1). Even with subsequent critiques claiming true attributable deaths of only 10% this number (2), the important messages of the IOM report should not be lost, namely:

  • Errors will occur;
  • Errors are usually multi-factorial and often represent problems with systems;
  • Many errors can be prevented by focusing on system issues;
  • A non-punitive environment is more likely to lead to solutions.

As Medical Toxicologists, we are often called upon to diagnose and treat patients with symptoms related to medication interactions or errors. How may we use these cases as opportunities to investigate the causes of the errors? Such "root cause analyses" are a component of most hospital adverse drug reaction reports, but these routinely suffer from incomplete reporting. Spurred on by reactions to the publication of the Institute of Medicine report and others, at least 15 state legislatures have passed laws requiring reporting of serious adverse events occurring in hospitalized patients to their respective departments of public health (e.g. Connecticut Public Act 02-125). Additionally, Federal legislation has been proposed. Although a response to the problem of preventable medical errors is certainly appropriate, it would surely be better for the medical profession to ensure the timely correction of our own systems that we recognize as flawed, but have previously accepted as immutable.

The Patient Safety Subcommittee of the American College of Medical Toxicology Practice Committee is instituting a forum for Medical Toxicologists to bring forward examples of errors and error prevention. In agreement with the editors of the Internet Journal of Medical Toxicology, we will publish reviews on error prevention, as well as representative cases of medical error and a systems approach to their correction.

This article will serve as a framework to visualize the many steps in the process of patient care that can lead to error. Our emphasis will be on medication and device errors, as these represent a majority of preventable errors (3).

System-Oriented Error Recognition and Reduction

Root cause analysis identifies common missteps in the systems that are invoked to carry out a variety of orders. If different physicians, nurses, or pharmacists make the same mistakes with different medications because of a defined system problem, that system should be changed. If a given medication or situation is frequently associated with errors, that particular medication or situation should be defined as "high-risk" and safeguards built into its use.

A medication error can occur at several different levels from the prescription, transcription, dispensing, or administration of the drug. Within each of these processes, there is the potential for errors in the selection of the drug or its dosage, the route and time of administration, and the patient to whom it should be administered. These have been quoted as the "right drug, right dose, right route, and right time for correct patient" rules. Obviously, the more steps in a process, the more room there is for mistakes. As an example, an illegible order may be transcribed incorrectly, leading to the dispensing of an incorrect drug or dose, which may then be administered to the patient. If the nurse questions the medication, this will lead to delays in administration and a break to workflow, resulting in problems for other patients. If the physician responds to questions defensively or arrogantly, the pharmacist or nurse will be dissuaded from questioning other orders, removing a potential system check. While each of these steps provides opportunities for system improvements, providing legible orders with a check-back system on administration (to the original order) would address the true cause of error. This type of analysis has led to a number of recommendations to decrease error at this point in the process, which may account for 1/3 of all medication errors (written communication, Michael Cohen, Institute for Safe Medication Practice). Some of these rules of order writing are noted in Table 1.

A number of other system responses have high yield in reducing medication errors. Examples include reducing the reliance on memory or vigilance by using protocols or computerized decision tools, and improved information display (4). Standardizing and centralizing error-prone medications or practices, such as with intrathecal chemotherapy, and reducing the number of hand-offs, whether it be information or people, are also important.

The Institute for Safe Medication Practices (ISMP) has promoted a systems approach for several decades, accumulating examples of errors that are amenable to the corrections listed above. While education is often touted as a method to improve care, its major role is to sensitize providers to the common problems. Changing behavior is more dependent on forcing functions and constraints, automation and standardized protocols, and checklists. Some of the areas open for improvement are listed in Table 2.

A framework utilizing these concepts is based on the "Swiss cheese" model of system incidents in Figure 1a, published by Reason (5). It emphasizes the multi-factorial nature of errors and the concept that several failures are necessary for such an error to reach the patient. While some errors are the result of a single individual thwarting these processes, or an unavoidable idiosyncratic reaction, the majority of errors are a failure of one or more systems. Each of theses systems may be considered a "defensive layer", whether comprising engineered controls (alarms, etc.), human controls, or procedural/ administrative controls (5). Applying this model to medication error yields Figure 1b; here, an error can occur only if each layer, composed of one of the controls discussed above, is breached (red line).

Examples of such system failures are manifold. One such system failure can be seen in the occurrence of benzocaine-induced methemoglobinemia (6). Failure occurs at the manufacturer's safeguard level with poorly-worded instructions. A portion of the instructions state that "Spray in excess of two seconds is contraindicated," a separate section states that "maximum anesthesia is produced in one minute," and therefore a healthcare professional may easily misinterpret the instructions as a one-minute spray. With a subsequent administrative safeguard failure (lack of a clear procedural policy) and a human safeguard failure (lack of awareness due to lack of feedback from previous failures), it is understandable that topical anesthetic-induced methemoglobinemia has been estimated to occur at 1 in 7,000 bronchoscopies (6). Certainly, all medical toxicologists involved with poison control centers are aware of calls from endoscopy suites regarding this adverse medication event. Yet how many of us have responded with specific region- or state-wide protocols or advisory letters to prevent future occurrences?

Another example of system failure occurs in the use of methylprednisolone in two forms, Solu-MedrolTM (methylprednisolone succinate) and Depo-MedrolTM (methylprednisolone acetate). A 3 year-old organ transplant recipient was due to receive 140 mg of Solu-Medrol daily on an outpatient basis. The patient had received an intravenous dose of Depo-Medrol instead, after the nurse had double-checked that Depo-Medrol and Solu-Medrol were both "methylprednisolone." This error was detected by the patient's mother only upon administration of the next day's dose, when she noticed that the correct formulation was "clear" while the previous (erroneous) dose had been "cloudy." While the child did not suffer an untoward event, failures in the system had to occur at multiple system safeguards: education, labeling (the warning against IV use of the depot form is in small print, Figure 2), and dispensing at the pharmacy and the bedside (7).

IJMT Educational Effort Towards Medication Error Reduction

Utilizing the framework of Figure 1b, we encourage ACMT members to submit case vignettes to the Internet Journal of Medical Toxicology (IJMT) that demonstrate these problems. These vignettes can be in the form of a short paragraph, with graphics provided for transcription errors, look-alike or sound-alike medications. The ideal submission would include a proposal of how this problem is or can be prevented from occurring again. It should be remembered that technology itself can introduce new sources of error (8). Reports of newly introduced sources of error from correction attempts would also be welcomed. Lack of knowledge and familiarity are often cited as proximate causes to preventable medication errors (9). Therefore, we encourage ACMT members to use these examples in their own educational efforts and review these system issues for adaptation to their own practices or institutions. We also thank those authors who have previously submitted manuscripts that have addressed patient safety and medication error issues. Links to these manuscripts are provided after the references.


1. Kohn LT, Corrigan JM, Donaldson M. To Err Is Human: Building a Safer Health System. Washington, DC: Institute of Medicine; 1999.

2. McDonald CJ, Weiner M, Hui SL. Deaths due to medical errors are exaggerated in Institute of Medicine report. JAMA 2000; 284(1): 93-5.

3. Leape LL. Error in medicine. JAMA 1994;272(23):1851-7.

4.       Bates DW,  Gawande AA. Improving safety with information technology.  NEJM 2003;348(25):2526-34.

5.       Reason J.  Human Error: models and management.  BMJ 2000;320(7237):768-770.

6.       Institute for Safe Medical Practice. Benzocaine-containing topical sprays and methemoglobinemia., October 3, 2002. (last accessed September, 2003)

7.       Institute for Safe Medical Practice. Mind your "Medrols"., May 29, 2003. (last accessed September, 2003)

8.       Ballentine AJ, Kinnaird D, Wilson JP.  Prescription errors occur despite computerized prescriber order entry. American Journal of Health-System Pharmacy 2003;60(7):708-9.

9.       Leape LL, Bates DW, Cullen DJ, et al: Systems analysis of adverse drug events. JAMA 1995; 274:35-43.


Further Reading
  1. Becker C. Scanning for higher profits. The FDA's plan to require bar codes on commonly used medical products will do more than improve patient safety. Modern Healthcare 2003;33(24):6-7,16.
  2. Bizovi KE, Beckley BE, et al. The effect of computer-assisted prescription writing on emergency department prescription errors. Acad Emerg Med 2002; 9(11):1168-75.
  3. Cucchiara B, Messe S, Kasner SE. Danger of treatment protocols. Stroke 2003;34(5):E19.
  4. Freedman JE, Becker RC et al. American Heart Association. Council on Clinical Cardiology Subcommittee on Acute Cardiac Care, Council on Cardiopulmonary and Critical Care, Council on Cardiovascular Nursing, and Council on Stroke. Medication errors in acute cardiac care: An American Heart Association scientific statement from the Council on Clinical Cardiology Subcommittee on Acute Cardiac Care, Council on Cardiopulmonary and Critical Care, Council on Cardiovascular Nursing, and Council on Stroke. Circ 2002;106(20):2623-9.
  5. Freund PR, Posner KL. Sustained increases in productivity with maintenance of quality in an academic anesthesia practice. Anesth Analg 2003; 96(4):1104-8.
  6. Gandhi TK, Weingart SN, et al. Adverse drug events in ambulatory care. NEJM 2003;348(16):1556-64.
  7. Kaushal R. Shojania KG. Bates DW. Effects of computerized physician order entry and clinical decision support systems on medication safety: a systematic review. Arch Int Med 2003;163(12):1409-16.
  8. Kozer E, Scolnik D et al. Variables associated with medication errors in pediatric emergency medicine. Pediatrics 2002;110(4):737-42.
  9. Lesar T, Mattis A, et al. VHA New England Medication Error Prevention Initiative Collaborative. Using the ISMP Medication Safety Self-Assessment to improve medication use processes. Joint Commission Journal on Quality & Safety 2003;29(5):211-26.
  10. Meadows M. Strategies to reduce medication errors. How the FDA is working to improve medication safety and what you can do to help. FDA Consumer 2003;37(3):20-7.
  11. Morrissey J. Encyclopedia of errors. Growing database of medication errors allows hospitals to compare their track records with facilities nationwide in a nonpunitive setting. Modern Healthcare 2003;33(12):40, 42.
  12. Peth HA Jr. Medication errors in the emergency department: a systems approach to minimizing risk. Emerg Med Clin North Amer 2003;21(1):141-58.
  13. Seifert SA, Jacobitz K. Pharmacy prescription dispensing errors reported to a regional poison control center. J Tox - Clin Tox 2002;40(7):919-23.
  14. Sherman FT. Older patients and the aging Columbia shuttle. Examining organizational accidents to prevent disastrous outcomes. Geriatrics 2003;58(3):13-4.
  15. Tierney WM. Adverse outpatient drug events--a problem and an opportunity. NEJM 2003;348(16):1587-9.
  16. Tranum D, Grasha AF. Susceptibility to illusions and cognitive style: implications for pharmacy dispensing. Perceptual & Motor Skills 2002; 95(3 Pt 2):1063-86.


We would like to thank our colleagues who have contributed previous articles to IJMT with regard to general issues of medication and patient safety, including:

Joshua G. Schier, MD
Lewis S. Nelson, MD
Robert S. Hoffman, MD
An Acetaminophen Dosing Error in A Child
Int J Med Toxicol 2003; 6(2): 7

Heather Long, MD
Lewis S. Nelson MD, FACMT, FACEP
Robert S. Hoffman, MD
Ketamine Medication Error Resulting in Death
Int J Med Toxicol 2003; 6(1): 2

Howard Greller, MD
Lewis S. Nelson MD, FACMT, FACEP
Physician-Patient Miscommunication Results in Medication Error
Int J Med Toxicol 2003; 6(1): 3

Bernhard Kuhn, M.D.
Kirsten Bechtel, M.D.
Carl Baum, M.D., FACMT

Dispensing Error: Calcium-Channel Blocker Substituted for Neuroleptic
Int J Med Toxicol 2001; 4(4): 26

The American College of Medical Toxicology

Medication Errors and Adverse Drug Reactions or Events (Position Statement)
Int J Med Toxicol 2001; 4(3): 23

Jennifer A. Lowry, MD
John C. Vandover, MD
Jan DeGreeff, RN
Anthony J Scalzo, MD
Unusual Presentation of Iatrogenic Phenytoin Toxicity in a Newborn
Int J Med Toxicol 2001; 4(1): 1

Kenneth Kulig, MD

Medication Errors and Adverse Drug Reactions or Events
Int J Med Toxicol 2001; 4(1): 13

William O. Robertson, MD
1999 Matthew Ellenhorn Award Lecture: Lessons from Medical Toxicology
Int J Med Toxicol 2000; 3(2): 3

Bruce Ruck, PharmD
Thelma Jennis MPH
Steven Marcus MD
Few NACCT Abstracts of Adverse Drug Reactions are Reported to MEDWATCH
Int J Med Toxicol 2000; 3(2): 4

Karen R. Schlafer, Doctor of Pharmacy Candidate
Christine M. Stork, PharmD., ABAT
Dermal Application of Nitroglycerin Ointment in Place of NystatinTM Ointment Results in Fatality
Int J Med Toxicol 2000; 3(2): 5

A Tentanus Look-alike Error
Int J Med Toxicol 2000; 3(2): 6

Bradley Moyer, MD
Walter Shrading, MD
Keith K. Burkhart, MD, FACMT
CELEXATM for CELEBREXTM ? A Case of Medication Sample Error
Int J Med Toxicol 2000; 3(2): 7

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