A medication error is an unintentional failure in the medicinal product therapy process that results in, or may result in, harm to the patient. The error lies in the process of prescribing, dispensing, preparation, or administration, and not necessarily in the intrinsic effect of the medicinal product. In European risk management, medication errors are considered separately because product design, name, strength, packaging, or the delivery system can facilitate incorrect actions.
Sources of error along the therapy process
Risks can arise as early as from similar medicinal product names, strengths that are difficult to distinguish, or ambiguous labelling. Further sources include dispensing, reconstitution, dose calculation, preparation, and administration. For example, a device may suggest incorrect handling, or a liquid medicinal product may be administered incorrectly without a suitable dosing aid. For assessment, it is important which element of the product or process enabled the error and which clinical outcome actually or potentially results from it.
The EMA distinguishes between incorrect actions with an adverse reaction, errors without harm, and intercepted potential errors. Reports without harm can also be relevant for risk management because they can reveal a recurring design or use problem. Marketing authorisation holders should capture such cases systematically and assess them scientifically, even if they do not meet the criteria for a reportable individual case safety report. Patterns should be included in the periodic safety evaluation.
Risk management and prevention
A mere collection of error reports is not sufficient. The RMP should consider potential sources of error throughout the entire product life cycle, including those arising from development. If error reports with adverse consequences are available, the error, together with the specific outcome, can be classified as an identified risk. Situations with a possible error but unclear harm may constitute a potential risk. If relevant to the benefit–risk balance or public health, this can become an important safety concern.
Depending on the cause, routine or additional risk minimisation measures may be appropriate. Clearer labelling, modified packaging, a dosing aid, training, or controlled dispensing can address different error mechanisms. Selection should be tailored to the observed process: for example, patient-facing material does not resolve a mix-up risk in storage, while a packaging change does not compensate for missing instruction on a complex device.
Distinction from adverse reaction and off-label use
With an adverse reaction, the focus is on the harmful and unintended reaction to a medicinal product; with a medication error, the starting point is an unintentional incorrect action in the therapy process. The two can coincide if an error causes an adverse reaction. Pharmacovigilance processing must then capture both the clinical outcome and the cause of the error.
Off-label use differs in that it is the deliberate use outside the authorised conditions. A medication error, by contrast, is unintentional. Prescribing the wrong strength may be an error; the intentional choice of a non-authorised indication is not. This distinction is essential for coding, root-cause analysis, and selecting appropriate preventive measures.
Root-cause analysis should distinguish between the immediate incorrect action and contributing conditions. An incorrect dose may result, for example, from an unclear concentration statement, a missing dosing aid, time pressure, or ambiguous training. Only this differentiation enables effective prevention. If reports are recorded solely as “user error”, product design deficiencies or systemic care problems remain invisible. In recurrent cases, it should also be assessed whether they reflect the same error mechanism or merely share the same clinical outcome; this determines whether a common risk measure is appropriate.
Ideally, prevention begins even before the first use in a patient. Human factors insights, feedback from trial sites, and experience with similar products can indicate weaknesses. After authorisation, this early assumption is tested against real-world error reports and, where necessary, corrected through changes to risk minimisation or product design.
Relevance for clinical trials
In clinical trials, medication errors often arise at interfaces between the investigational medicinal product, randomisation, reconstitution, dispensing, and patient training. Trial documents should therefore contain unambiguous instructions on dose, storage, preparation, and return. An error report needs information on the actual process, exposure, immediate actions taken, and the clinical outcome. Only then can it be determined whether the problem was caused by training, the protocol, packaging, or a product characteristic.
Full-service CROs such as Mediconomics provide support through error-capture processes, review of case report forms, training of trial sites, and analysis of recurring use patterns. They coordinate assessment with Medical Monitoring, Drug Safety, and clinical logistics, and help implement preventive changes in manuals, training materials, or trial processes in a traceable manner.
Frequently asked questions (FAQ)
Is an intercepted error relevant for pharmacovigilance?
Yes. Even without harm occurring, it can indicate a risk in the therapy process and should be considered for root-cause analysis.
When does a medication error become an important safety concern?
If its risk can affect the benefit–risk balance or public health, it may be included in the RMP as an important safety concern.
Can an adverse reaction occur without an error?
Yes. An adverse reaction can occur with correct use; a medication error, by contrast, requires an unintentional failure in the therapy process.
Regulatory references
- EMA “Medication errors” – describes capture, assessment, and the RMP link within the EU system.
- EMA Good Practice Guide “Risk minimisation and prevention of medication errors” – addresses sources of error and prevention approaches.
- Directive 2001/83/EC, Article 102 – includes suspected reports arising from medication errors.