Table 1

 Medication related event types: definitions and examples (adapted from Kaushal et al3)

Event typeDefinitionExample
ADE, adverse drug event.
ADEActual injuries resulting from medical interventions related to a medicineTroublesome drug rash requiring intervention
    Preventable ADEActual injuries resulting from the use of medication in errorThe development of a rash after administration of flucloxacillin in a patient known to be allergic to penicillins
    Non-preventable ADEActual injuries resulting from the use of a medication not associated with error, also termed adverse drug reactionsThe development of a rash after administration of flucloxacillin in a patient with no known drug allergies
Potential ADEEvents that have a significant potential for injuring a patient but do not actually cause harm. This may be because they are intercepted before reaching the patient or, due to particular circumstances or chance, the patient is able to tolerate the errorA prescription order written for a 10-fold overdose of digoxin that is intercepted and corrected by the pharmacist before reaching the patient. A non-intercepted potential ADE would be the administration of a non-steroidal anti-inflammatory agent to a patient with asthma who does not experience any adverse effects
Medication errorHarmless errors associated with the use of a medicationAdministration of one regular dose of non-critical medication given more than 2 hours later than scheduled
Rule violationFaulty medication orders with little potential for harm or extra work because they are typically interpreted correctly by pharmacy and nursing staff without additional clarificationPrescription written for regular medication but not dated
Other eventsAny reported events not classified as one of the other four event typesMild side effects that are tolerated without need of intervention or general practice related issues