Medication error is defined as any preventable event that may cause or lead to inappropriate medication use or patient harm while the medication is under the control of the healthcare professional, patient, or consumer.⁴ Medication errors can be classified by considering the types of errors occurring, such as wrong patient, dose, infusion rate, delivery route or medication.

Medication errors may occur during any phase of the drug delivery process from prescription to drug administration and at anywhere medications are administered.³ Errors may occur with any medication; however, chemotherapy presents unique dangers due to narrow therapeutic indices, potential toxicity even at therapeutic dosages, complex regimens, and a vulnerable cancer patient population.⁶

Generally speaking, wrong drug dosages can occur during all steps of the treatment process. During a 2-year period (2003-2004), Ford⁶ conducted a prospective study on the oncology ward of a large community hospital on medication errors. They identified 141 errors in total, thereof 38 were classified as “wrong dose”. Of these, one occurred during ordering / transcription, 20 during dispersion and 17 during application. Additional 18 errors were “medication not given”. 

Marked inaccuracies in IV fluid infusion rates are common, and do not seem to be perceived by staff as important. Metered pumps have been shown to improve accuracy. Rooker et al.¹³ studied the IV infusion rates in patients requiring continuous IV fluids during a four-week period. The periods over which iv crystalloid fluid bags were administered were compared with the time prescribed. 

Most of the chemotherapy regimes are given intravenously, i.e. directly into the venous system. Peripheral venous access may be suitable, however, given the high toxicity of the drugs, mostly central venous access are preferred.

Antineoplastic agents are mostly classified as high-alert medications. These are medications that pose an increased risk of patient harm when involved in medication errors.²⁴

A majority of wrong medication errors derives from prescriptions, one of the causes being sound-alike drugs (name similarity). 

Errors are also costly in terms of opportunity costs. Dollars spent on having to repeat diagnostic tests or counteract adverse drug events are dollars unavailable for other purposes. Purchasers and patients pay for errors when insurance costs and copayments are inflated by services that would not have been necessary had proper care been provided. It is impossible for the nation to achieve the greatest value possible from the billions of dollars spent on medical care if the care contains errors.

But not all the costs can be directly measured. Errors are also costly in terms of loss of trust in the system by patients and diminished satisfaction by both patients and health professionals. Patients who experience a longer hospital stay or disability as a result of errors pay with physical and psychological discomfort. Healthcare professionals pay with loss of morale and frustration at not being able to provide the best care possible and society, in general, pay in terms of lost worker productivity, reduced school attendance by children, and lower levels of population health status.²⁸

“It may be part of human nature to err, but it is also part of human nature to create solutions, find better alternatives and meet the challenges ahead”. On their landmark publication in 1999, Kohn and colleagues of Institute of Medicine (IOM) called the entire healthcare sector to action.²⁸ The IOM panel called for a transformation in the way health-care professionals understand medical error by applying principles from cognitive psychology and human factors, the study of human performance in work environments. Improvements in aviation and other safety-oriented industries, such as chemical engineering, manufacturing, and nuclear power, showed that complex systems, rather than individual practitioners, were the primary sources of error and a target for improvement opportunities through simplification, standardization, and technology.³⁰

This has in the same year been called “Swiss Cheese Model”, referring to multiple layers of safety shields to prevent errors (holes in the cheese) to reach the patient.²⁹ This model has been the conceptual foundation for the development of Critical Incident Reporting Systems for the reporting of and learning from critical incidents and near misses.

The American Society of Hospital Pharmacists (ASHP) consequentially developed a guideline on Preventing Medication Errors with Chemotherapy and Biotherapy in 2002 which has recently been updated.³² The guideline comprises recommendations for healthcare organizations, for multidisciplinary monitoring of medication use and verification, for prescribing systems and prescribers, for medication preparation and dispensing systems and roles for pharmacists, for medication administration systems and roles for nurses, for patient education, for manufacturers and regulatory agencies, and recommendations for identifying and managing medication errors.

Wrong administration techniques may comprise multiple aspects of the infusion. One example is discussed in the following: 

Particles arising from infusion therapy may induce or aggravate inflammatory response syndromes. They have been shown to generate thrombosis, impair microcirculation, and modulate immune response. Sources of particles include components of infusion systems, incomplete reconstitution of solutions or drug incompatibility reactions. Up to one million particles may be infused per patient per day. In-line filters incorporated into infusion lines retain particles and thereby nearly entirely prevent their infusion.³³

Others would be errors in assembling giving sets for secondary infusions with or without pumps, Luer access-devices unintentionally left open after use or needlestick injury due to needle-based manipulation. 

Incidents involving patient misidentification (e.g., “wrong patient” errors) are not uncommon in oncology practice. Many of these incidents are near-miss or close-call situations that are averted at some point prior to reaching the patient. Patient misidentification is under-reported and its incidence is unknown.³⁴