Medication Dispensing Errors and Prevention

In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2024 Jan.


Close to 6,800 prescription medications and countless over-the-counter drugs are available in the United States. To further complicate a practitioner's responsibility during patient care, there are thousands of health supplements, herbs, potions, and lotions used by the public regularly to treat their health problems. With the number of substances on the market, it is conceivable that mistakes can be made when practitioners prescribe or dispense drugs. Added to this is the high risk of interaction between substances.

Each year, in the United States alone, 7,000 to 9,000 people die due to a medication error. Additionally, hundreds of thousands of other patients experience but often do not report an adverse reaction or other complications related to a medication. The total cost of looking after patients with medication-associated errors exceeds $40 billion each year, with over 7 million patients affected. In addition to the monetary cost, patients experience psychological and physical pain and suffering as a result of medication errors. Finally, a major consequence of medication errors is that it leads to decreased patient satisfaction and a growing lack of trust in the healthcare system.

The most common reasons for errors include failure to communicate drug orders, illegible handwriting, wrong drug selection chosen from a drop-down menu, confusion over similarly named drugs, confusion over similar packaging between products, or errors involving dosing units or weight. Medication errors may be due to human errors, but it often results from a flawed system with inadequate backup to detect mistakes.


Medication Error

While there is no uniform definition of a medication error, The National Coordinating Council for Medication Error Reporting and Prevention defines a medication error as: “… any preventable event that may cause or lead to inappropriate medication use or patient harm while the medication is in the control of the healthcare professional, patient, or consumer. Such events may be related to professional practice, health care products, procedures, and systems, including prescribing; order communication; product labeling, packaging, and nomenclature; compounding; dispensing; distribution; administration; education; monitoring; and use.” However, there is no widely accepted uniform definition. Unfortunately, untoward medical errors and underreported medication errors result in significant morbidity and mortality.

Adverse Drug Reaction

The World Health Organization defines an adverse drug reaction as “any response that is noxious, unintended, or undesired, which occurs at doses normally used in humans for prophylaxis, diagnosis, therapy of disease, or modification of physiological function.” Adverse drug reactions are expected negative outcomes that are inherent to the pharmacologic action of the drug and not always preventable, while medication errors are preventable.

Adverse Drug Event

An adverse drug event is an injury from a medication or a missed or inappropriately dosed medication. An adverse drug event causes morbidity or mortality to a patient. The difference between an adverse drug reaction and an adverse drug event is that in an adverse drug event, the patient must be exposed to a medication with a negative consequence, which may or may not be expected. For adverse drug events, the patient suffers a negative consequence from receiving a drug in the usual manner it was intended, did not receive a medication that was required, or received the medication in a manner that was inappropriate such as too high or low a dose.

Medication Misadventure

A medication misadventure is an iatrogenic incident that is inherent to medication therapy. Medication misadventure includes medication errors, adverse drug reactions, and adverse drug events. It is created through omission or commission of medication administration. Medication misadventures always are undesirable and unexpected; they may or may not be independent of preexisting pathology; and might be due to human or system error, idiosyncratic, or immunologic response.

Sentinel Event

The Joint Commission defines a sentinel event as “an unexpected occurrence involving death or serious physical or psychological injury, or the risk thereof. Serious injury specifically includes loss of limb or function. The phrase ‘or the risk thereof’ includes any process variation for which a recurrence would carry a significant chance of a serious adverse outcome.” Sentinal events may include medication errors, adverse drug events, and medication misadventures. Sentinel events cause significant morbidity or mortality and are possibly preventable.

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