Medication errors: prescribing faults and prescription errors (2024)

Abstract

Keywords: drug monitoring, drug prescription, fault, medication error, training

Prescribing faults and prescription errors are major problems among medication errors. They occur both in general practice and in hospital, and although they are rarely fatal they can affect patients' safety and quality of healthcare. A definition states that a ‘clinically meaningful prescribing error occurs when … there is an unintentional significant reduction in the probability of treatment being timely and effective or increase in the risk of harm when compared with generally accepted practice’[1]. This definition is clearly oriented to the outcome of the error. However, it does not take into account failures that can occur during the whole process of prescribing, independently of any potential or actual harm [2]. Prescription errors encompass those related to the act of writing a prescription, whereas prescribing faults encompass irrational prescribing, inappropriate prescribing, underprescribing, overprescribing, and ineffective prescribing, arising from erroneous medical judgement or decisions concerning treatment or treatment monitoring [3, 4]. Appropriate prescribing results when errors are minimized and when the prescriber actively endeavours to achieve better prescribing: both actions are required.

Prevalence

The prevalence of prescribing faults and prescription errors has been quantified in prospective and retrospective cohort studies. Internal or external reviews of prescriptions, performed mostly by experienced pharmacists, or direct interviews or voluntary reports from prescribers have been used as sources of information [4, 5]. Depending on the reference parameters used, the observed incidence varies greatly. It is usually higher in process-oriented studies, which evaluate the presence in the prescription of potentially harmful errors, than in outcome-oriented studies, which mostly evaluate the incidence of preventable adverse drug effects. Prescription errors account for 70% of medication errors that could potentially result in adverse effects. A mean value of prescribing errors with the potential for adverse effects in patients of about 4 in 1000 prescriptions was recorded in a teaching hospital. Such errors are also frequent in ambulatory settings [4–6]. However, given the inconsistency of the criteria used to identify errors and the various definitions used, it is not surprising that a recent meta-analysis showed that the range of errors attributable to junior doctors, who are responsible for most prescriptions in hospitals, can vary from 2 to 514 per 1000 prescriptions and from 4.2 to 82% of patients or charts reviewed [7].

Sources

All procedures related to prescribing are error-generating steps. A prescribing fault can arise from the choice of the wrong drug, the wrong dose, the wrong route of administration, and the wrong frequency or duration of treatment, but also from inappropriate or erroneous prescribing in relation to the characteristics of the individual patient or co-existing treatments; it may also depend on inadequate evaluation of potential harm deriving from a given treatment [3, 8]. Errors in dose selection occur most commonly, and represent >50% of all prescribing faults.

Inaccuracy in writing and poor legibility of handwriting, the use of abbreviations or incomplete writing of a prescription, for example by omitting the total volume of solvent and duration of a drug infusion, can lead to misinterpretation by healthcare personnel. This can result in errors in drug dispensing and administration. Unintended omissions – or failure to withdraw a drug – are also frequent. A critical point is the transcription of previous treatments at the time of admission to hospital, so-called ‘medication reconciliation’. Unintended omission or changes in the dosing regimen are frequent, and account for 15–59% of medication errors [9]. Inaccurate medication history taking can cause omission of treatment, resulting in potential harm in more than one-third of patients taking more than four drugs [10]. Transfer of a patient's care within the same institution or between a hospital and a general practitioner also favours prescribing faults due to omission [11].

Why do these errors occur? According to the theories of human error, errors in prescribing, as in any other complex and high-risk procedure, are occasioned by and depend on failure of individuals, but are generated, or at least facilitated, by failures in systems [12]. It might therefore be expected that the larger the number of prescriptions, and the more steps in the prescribing procedure, the higher the risk of error.

Prescription errors are typically events that derive from slips, lapses, or mistakes [2], for example, writing a dose that is orders of magnitude higher or lower than the correct one because of erroneous calculation, or erroneous prescription due to similarities in drug brand names or pharmaceutical names [13]. Human factors may therefore be the first identifiable causes of error. However, in most cases, analysis of error-inducing conditions shows an unsafe environment as the ‘latent condition’ that contributes to the accident. According to Reason's ‘Swiss cheese’ model of accident causation, sequential failures in the system and insufficient defences and counteractions are required for the event to occur [14]. In the case of prescribing errors, inadequate feedback control or lack of cooperation between doctor and nurses, with undefined roles concerning responsibility in prescribing, generate a cascade of errors that can lead to an adverse effect. Among doctors, stressful conditions, a heavy workload, a difficult work environment, insufficient communication within the team, and not being in good physical and mental condition are among the primary causes of prescribing faults and prescription errors [8].

Inappropriate prescribing most often derives from a wrong medical decision, because of lack of knowledge or inadequate training. Junior doctors often work in stressful circ*mstances that are perceived as routine by experienced doctors. Errors are more frequently made by junior members of staff and inadequate knowledge or training often underlie inappropriate prescribing and other faults [3, 8]. Inadequate staffing, lack of skills and knowledge of relevant rules, tasks outside the routine, or taking care of another doctor's patient have also been identified as conditions associated with prescribing faults [8].

Adverse outcomes can be related to lack of knowledge or skill. Even the apparently simple act of transcribing previous medications and collecting information as part of the medication history requires a knowledge of pharmacotherapy as well as adequate information about the patient's clinical condition. Equally, the choice of dose requires information about the patient's clinical status and immediate verification of the appropriateness of treatment.

Factors related to patients can also result in errors, leading to adverse effects, since these are associated in most cases with identifiable clinical conditions, such as reduced renal and hepatic function or a history of allergy requiring atypical or unusual dosage and frequency [3, 15]. Polypharmacy and management of elderly patients or children are associated with inappropriate or potentially inappropriate prescribing and errors [15]. Monitoring of drug action is necessarily part of the prescribing process, to allow optimization or adjustments of doses or treatments. In ambulatory care, prescribing faults are mostly related to the use of inappropriate doses and inadequate monitoring [16].

Prevention

Acquisition of information through error-reporting systems is a prerequisite for preventing prescribing faults and prescription errors, as is the adoption of shared criteria for the appropriateness of procedures. Error-reporting systems, both internal and external to healthcare institutions, have been widely used [14, 17–19]. Reporting is usually voluntary and confidential, but must be timely and evaluated by experts, in order to identify critical conditions and allow systems analysis. Prescribers should be informed and become aware of errors that have been made in their environment and of the conclusions of the analysis.

Spontaneous reporting is about 10 times less effective in detecting errors and potential adverse effects than active interventions, such as chart review and patient monitoring [20]. Active, systems-oriented interventions aimed at improving processes, rather than individual performance, should therefore be advocated [14, 21]. Three major intervention strategies can be adopted:

• reduction of complexity in the act of prescribing by the introduction of automation;

• improved prescribers' knowledge by education and the use of on-line aids;

• feedback control systems and monitoring of the effects of interventions [22].

Conclusion

Errors and faults in prescribing are in most cases preventable. Intervention strategies should be primarily focused on education and the creation of a safe and cooperative working environment, to strengthen defence systems and minimize harm to the patient.

Systems-oriented interventions increase awareness of risk among healthcare personnel [14]. Interventions aimed at improving knowledge and training, and reducing complexity, and the introduction of strict feedback control and monitoring systems are highly advisable. However, large-scale information on the beneficial effects of interventions aimed at reducing harm from prescribing faults and prescription errors is not yet available and is needed.

Competing interests

None to declare.

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