Medication errors

 

Fig: Human error theory. Unintended errors may occur because the prescriber fails to complete the prescription correctly (a slip; e.g. writes the dose in 'mg' not 'micrograms') or forgets part of the action that is important for success (a lapse; e.g. forgets to co-prescribe folic acid with methotrexate); prevention requires the system to provide appropriate checking routines. Intended errors occur when the prescriber acts incorrectly due to lack of knowledge (a mistake; e.g. prescribes atenolol for a patient with known severe asthma because of ignorance about the contraindication); prevention must focus on training the prescriber.

Medication errors

A medication error is any preventable event that may lead to inappropriate medication use or patient harm while the medication is in the control of the health-care professional or patient. Errors may occur in prescribing, dispensing, preparing solutions, administration or monitoring. 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.

   Medication errors are very common. Several thousand medication orders are dispensed and administered each day in a medium-sized hospital. Recent UK studies suggest that 7-9% of hospital prescriptions contain an error, and most are written by junior doctors. Common prescribing errors in hospitals include omission of medicines (especially failure to prescribe regular medicines at the point of admission or discharge, i.e. 'medicines reconciliation'), dosing errors, unintentional prescribing and poor use of documentation.

      Most prescription errors result from a combination of failures by the individual prescriber and the health-service systems in which they work. Health-care organizations increasingly encourage reporting of errors within a 'no-blame culture' so that they can be subject to 'root cause analysis' using human error theory. Prevention is targeted and can be supported by prescribers communicating and cross-checking with colleagues (e.g. when calculating doses adjusted for body weight, or planning appropriate monitoring after drug administration), and by health-care systems providing clinical pharmacist support (e.g. for checking the patient's previous medications and current prescriptions) and electronic prescribing (which avoids errors due to illegibility or serious dosing mistakes, and may be combined with a clinical decision support system to take account of patient characteristics and drug history, and provide warnings of potential contraindications and drug interactions).

All prescribers will make errors. When they do, their first duty is to protect the patient's safety. This will involve a clinical review and the taking of any steps that will reduce harm (e.g. remedial treatment, monitoring, recording the event in the notes, informing colleagues). Patients should be informed if they have been exposed to potential harm. For errors that do not reach the patient, it is the prescriber's duty to report them, so that others can learn from the experience and take the opportunity to reflect on how a similar incident might be avoided in the future.