Medication errors

A medication error is 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 or patient. A prescribing error is a medication error related to an error in prescribing. Many ADRs are considered in retrospect to have been ‘avoidable’ with more care or forethought. In other words, an adverse event considered by one prescriber to be an unfortunate ADR might be considered by another to be a prescribing error. An administration error is related to a failure in the task of giving the medicine to the patient, even though the prescription that directs the administration is correct and the correct medicine has been supplied (e.g. the medicine is given by the wrong route). A dispensing error occurs when the prescription is correct but the wrong medicine is supplied, normally be a pharmacist.

Causes of prescribing errors

The causes of prescribing errors can be conveniently divided into those that relate to the individual prescriber and those relating to the system in which they work. In the past it was common to seek to attribute blame for errors on individuals it is now recognised that most errors result from a combination of individual (active) and systems (latent) failures. Healthcare organisations increasingly encourage reporting of errors within a ‘no blame culture’ so that they can be subject to ‘root cause analysis. A well known basis for analysis is Human Error Theory which seeks to categorise errors into those actions that are unintended, skill-based and avoidable by more thorough checking routines, and those that are intended and related to lack of knowledge or experience. Resource constraints mean that prescribers will always work in sub-optimal circumstances emphasising the need for rigorous training and attention to detail when prescribing which, will both enable them to cope with these shortcomings more effectively.

Prevalence of medication errors

Medication errors are very common. Several thousand medication orders are dispensed each day in a medium sized hospital and even a small error rate would imply many events. The rates measured will vary according to definition, patient population, setting, resourcing, workload, patient complexity and identification method. However, most studies indicate that medication errors are endemic in all healthcare settings. Prescribing errors are a major contributor to the total and recent UK studies suggest that 7–9 % of hospital prescriptions contain an error.

Classification of medication errors

Medication errors are usually classified on the basis of which stage of the medication process they occur.

Prescribing errors involve a failure to order the right drug at the right dose for the right patient
Dispensing errors involve a failure to supply the right drug at the right dose for the right patient
Preparation errors involve a failure to prepare the right drug at the right dose for the right patient
Administration errors involve a failure to administer the right drug at the right dose by the appropriate route and method for the right patient
Monitoring errors involve a failure to check the administration and effect of a medicine

Medication errors can also be categorised on the basis of the harm they cause, ranging from those that didn’t reach the patient through to those that contribute to death, the healthcare professional involved or whether they involve commission or omission.