As medical errors are a major problem in the UK and many other countries, policy initiatives have been implemented to reduce them.1^–4 In the UK, an estimated 850 000 adverse events occur annually in NHS hospitals, resulting in £2 billion in direct costs for additional hospital days alone, of which half may be avoidable.2 In addition, there may be great personal costs to those involved including patients, their families and staff. Public confidence is also undermined.

MEDICATION ERRORS

Medication errors are considered to be the commonest type of medical error.1^–3 In the current literature, large variations in the definitions and categories of medication errors, the methodologies of research, study settings and countries mean reported error rates differ greatly.5 A definition of medication errors accepted by the UK Department of Health and the US National Co-ordinating Council for Medication Error and Prevention reads as follows4:

… any preventable event that may cause or lead to inappropriate medication use or patient harm, while the medication is in the control of the health care professional, patient, or consumer. Such events may be related to professional practice, health care products, procedures and systems including: prescribing, order communication, product labelling, packaging and nomenclature, compounding, dispensing, distribution, administration, education, monitoring, and use.

As studies may report on prescribing, transcribing, dispensing and/or drug administration errors, comparisons of results must be interpreted with caution. It is acknowledged that the true incidence of medication errors in the UK is unknown.6

PAEDIATRICS

To date most medication error studies have been carried out in adults. However, potential adverse drug events (this term includes adverse drug reactions and medication errors) may be up to three times more common in children than in adults.7 Most potential reported adverse drug events are dosing errors and errors involving intravenous drug administration. The UK Department of Health has recognised that children are a particularly challenging group of patients as regards the safe use of medicines.4 8

Recently published literature reviews have established that medication errors are a significant problem in paediatric practice.5 9 Another review has also suggested that the true incidence of paediatric dosing errors could be approximately 500 000 per year in England. There is, therefore, an urgent need to minimise such errors.10 The British National Formulary for Children (BNFC) has provided some useful general guidance on the writing of prescriptions and the supply and administration of medicines.11 The guidance is useful for the individual prescriber, nurse and pharmacist. The American Academy of Pediatrics (AAP) has also recognised the importance of identifying and managing medication errors in children. The AAP Committee on Drugs and Committee on Hospital Care emphasise the importance of systems change in detecting and preventing medication errors in inpatients. They make a large number of recommendations covering not only prescribers, pharmacists and nurses but also the hospital system and parents.12

CAUSES OF PAEDIATRIC MEDICATION ERRORS

It is important to understand the risk factors and causes of paediatric medication errors so that effective error reduction strategies can be proposed. We will briefly discuss the causes below.

Individualised dosing

Drug doses in the paediatric population are usually calculated individually, based on the patient’s age, degree of prematurity in neonates, weight or body surface area, and clinical condition. This leads to increased opportunities for dosing errors.13 14

Calculation errors and lack of appropriate formulations

Evidence confirms that some healthcare professionals have difficulty calculating the correct dose.15^–17 Ten-fold and greater dosing errors occur due to calculation mistakes, misplacement of the decimal point, the omission of zeroes before the decimal point, the use of trailing zeroes, incorrect expression of the dosage regimen and incorrect units (eg, milligrams instead of micrograms or millilitres).

This is compounded by the fact that many formulations are designed for use in adults, with few drugs being commercially available in suitable dosage forms18 or, more importantly, the correct strength, for children. As a result, complex calculations and dilutions are required to arrive at the appropriate formulation and dose for children19 20

Unfamiliarity with the paediatric population and/or treatment

It should be apparent that clinicians should not prescribe for children if they are not familiar with the paediatric population and/or the drugs they are using. However, junior doctors are frequently left by senior clinicians to prescribe medicines for children and lack of training,21 22 experience and supervision can lead to devastating errors.23

Interface issues

Confusion can result when a paediatric patient is discharged from hospital on an unlicensed medicine. Good communication between the hospital, the community pharmacy and the medical practitioner is essential in order to maintain an appropriate supply of the child’s medicine.24 In some cases, it may be necessary to purchase the medicine from a “specials” manufacturer or prepare it extemporaneously. However, such preparations are patient specific and information about dosing regimes, formulations and monitoring requirements are often not readily available in the community. Errors have occurred where patients have been prescribed incorrect strengths and doses, resulting in serious medication errors and hospitalisation.18 The BNFC provides valuable information to community pharmacists and general practitioners to minimise the risk of prescribing and dispensing errors.11

EXAMPLES OF COMMON MEDICATION ERRORS

Table 1 lists the medicines most commonly responsible for different types of medication errors.25

Prescribers should take particular care with these medicines and hospitals should implement systems to minimise the risk of error. For example, limiting the types of intravenous fluids available may decrease the risk of hyponatraemia caused by the infusion of hypotonic solution. Also, removing concentrated potassium chloride for injection from ward stock decreases the chance of accidental intravenous injection and subsequent cardiac arrest.26

Sedatives including opiates and benzodiazepines can cause under- and oversedation. Severe neurological outcomes and respiratory depression as a result of oversedation can be minimised by an appropriate hospital policy.27 Many of the medicines used for sedation have a narrow therapeutic window and a small error in calculating the dose or the child’s weight can result in respiratory arrest. Appropriate monitoring and follow-up of patients who have received sedatives can prevent adverse outcomes by quickly identifying over-sedation or prolonged sedation. Under-sedation can very occasionally lead to procedures being abandoned with potential risks to the patient, a situation which should also be covered by hospital policy.

STRATEGY TO MINIMISE MEDICATION ERRORS IN CHILDREN

Electronic prescribing and computerised physician order entry (CPOE)

Electronic prescribing and computerised physician order entry (CPOE) systems allow physician orders to be entered on a computer rather than on paper. These systems generally contain some clinical decision support systems, such as patient allergy alerts or suggestions for drug doses and frequencies. A recently completed systematic review commissioned by the Department of Health in England concluded that most electronic prescribing and CPOE had resulted in significant reductions in medication errors in the paediatric inpatient population.28 Furthermore, a recently published study in the UK also demonstrated that electronic prescribing can reduce medication errors in a paediatric nephrology outpatient clinic.29 However, as pointed out by Walsh et al, the introduction of computers into hospitals simply moves the opportunity for error to the man–machine interface. The overall rate of errors is reduced, but new errors, such as typographical mistakes, emerge.9 Therefore, it is important to continue to monitor errors by pharmacists and rectify problems by making appropriate changes to the computer programme as soon as problems appear.

The cost of developing and implementing electronic prescribing is high and requires total commitment from hospital management, clinical and IT staff. The UK is in the early stages of widespread introduction of CPOE systems involving the NHS Connecting for Health Programme which is working to introduce electronic prescribing systems in hospital and primary care settings.30 It is likely that a few more years are needed for the NHS Connecting for Health Programme to fully implement electronic prescribing for children in the UK. In the meantime, some other useful strategies can be employed to minimise medication errors in children.

Clinical pharmacy service

Another recently published systematic literature review31 has found that pharmacists play an important role in paediatric medication error reduction. Almost all the studies reviewed have shown that pharmacists reduce adverse drug events. In another inpatient paediatric medication errors study, physician raters estimate that 81% of errors could have been avoided with pharmacist monitoring and that 47% could have been avoided by improved communication between physicians and pharmacists.32

Prescriber

Paediatric prescribers should be familiar with both children and the drug that they are prescribing; hence appropriate continuous professional development and training are essential to minimise medication errors.22 Drug allergies should be checked and noted on the drug chart. The clinician should also confirm that the patient’s weight is correct and recorded on each drug chart. The weight-based dose should not exceed the recommended adult dose. Finally, it is important to write legible prescriptions.

Calculation

For critical and high risk medicines, prescribers should document the calculation so that it can be checked. Then if possible, the calculation should be double checked by other staff depending on local policy.

Administration

Nurses and clinicians should check the drug, the dose, patient identity and any other relevant information before administering medicine. As mentioned in the previous section, 10-fold overdoses in children, particularly neonates can occur; therefore, such tasks should be carried out by nurses and prescribers who are competent in paediatric practice. Last but not least, when a query arises as to whether a drug should be administered, the patient, parent or caregiver should be listened to attentively, their questions should be answered, and the prescription should be double checked with the prescriber.

Hospital environment

Hospitals should provide sufficient qualified staff and a suitable work environment for the safe and effective use of medicines. Staff should also receive adequate training and continuous education in the use of paediatric medication, including regular testing of their ability to calculate paediatric doses.

The introduction of standardised equipment (eg, a hospital-wide standard infusion pump, use of smart programmable pumps) and measurement systems should eliminate many calculation errors and reduce the time required for dose calculation.

A well developed medication errors reporting system will allow hospitals to collect vital information for root cause analysis and risk assessment. It is therefore important to eliminate barriers to reporting and encourage a non-punitive culture by emphasising that the information will be used to improve clinical practice and ultimately patient care. The National Patient Safety Agency (NPSA) in England has set up the National Reporting and Learning System (NRLS) for anonymous reporting of patient safety errors and systems failures by health professionals across England and Wales. These confidential data are regularly analysed by the NPSA to identify national patient safety trends and priorities and to develop practical solutions33 with the aim of helping the NHS to learn from mistakes. As of March 2008, over 2 million patient safety incidents have been reported to the NRLS33 and several safety warnings have been issued based on these reports.34

Error reporting systems are known to underestimate the incidence of medication errors and the reporting rate can be greatly affected by the reporting culture. Although they are helpful for developing practical solutions, such systems are not useful tools for epidemiological research.

Finally, every hospital should develop and maintain a system for informing families of errors and providing feedback to staff.

Communication

At present, there is little information that improved communication between professionals or with patients will prevent paediatric medication errors.35 However, there is evidence from projections based on analysis of the types of current errors that improved communication could potentially reduce errors.35 Fortescue et al noted that 47% of all inpatient drug errors could have been prevented by improved communication between doctors and pharmacists,32 and furthermore that improved communication between doctors and nurses could have prevented 17.4% of all errors. Communication between health professionals is also crucial, particularly when patients are being transferred between secondary and primary care; medication errors are not uncommon due to poor or even a complete lack of written communication. Patient information leaflets and discharge summaries can be very useful to prevent medication errors.24

Sources of prescribing information

One of the overriding problems in prescribing for children is the lack of official prescribing information.36 It is well documented that many common medications are used off label in children as the product information offers no paediatric guidance. Therefore, for such medications, the dose should be checked against that recommended in the BNFC,11 which is an annually revised compendium of current dosing information for children. It is available as a hard copy and electronically.37 For the rare occasion where the prescriber is using a medicine not covered by the BNFC, other useful resources include Micromedex,38 The Medical Letter,39 the Merck Pediatrics manuals40 and the Drugs and Therapeutics Bulletin.41 Alternatively, prescribers can contact the pharmacy of their local children’s hospital for further information.

PRIORITISING STRATEGIES FOR PREVENTING MEDICATION ERRORS

Strategies should be prioritised according to local needs and resources. For example, in England, the NHS Connecting for Health Programme will eventually implement CPOE in all NHS trusts and hence CPOE is unlikely to be high priority for individual hospitals in England. On the other hand, it could be a top priority for hospitals in other parts of the world. There is sufficient evidence31 32 to recommend the setting up of clinical pharmacy services, particularly ward-based prescription monitoring services, as a second priority; this will also improve communication between health professionals. The third priority is the education and training of health professionals in the use of paediatric medicines. Standardisation of equipment should also be implemented should resources be available.

CONCLUSION

Medication errors are common and children are at particular risk. Children, because of their variable size and physiology, are vulnerable to overdose as well as underdose. Furthermore, their inability to self-advocate may increase their vulnerability. A systematic approach to the prevention of medication errors is needed in the paediatric setting.