A substantial body of evidence from international literature points to the risks posed by medication errors and the resulting preventable adverse drug effects. In the USA, medication errors are estimated to harm at least 1.5 million patients per year, with about 400 000 preventable adverse events [1]. In Australian hospitals about 1% of all patients suffer an adverse event as a result of a medication error [2]. In the UK, of 1000 consecutive claims reported to the Medical Protection Society from 1 July 1996, 193 were associated with prescribing and medications [3]. Medication errors are also costly – to healthcare systems, to patients and their families, and to clinicians [4, 5].