• Medication error
• medication safety
• patient safety

De Winter et al (see page 371) studied 3594 patients admitted to hospital through an emergency department and found that 59% of patients had a discrepancy between the physician's medication history and a pharmacist technician's structured medication history.1 This result is consistent with over 20 small studies (median sample size 104 patients) showing 61–67% of patients have at least one discrepancy in the medication history at the time of hospital admission.2

There are at least three good reasons to obtain an accurate medication history at the time of hospital admission. First, more than 1 in 9 emergency department visits are due to drug-related adverse events.3 An accurate medication history will be the cornerstone for diagnosing this common problem. Second, medication history errors may result in incorrect medication orders and incorrect treatment during the admission, leading to patient harm. Third, an accurate medication history is the foundation for accurate medication instructions and prescriptions at the time of hospital discharge.

Medication reconciliation (Med Rec) at admission is the process of obtaining the best-possible medication history (BPMH), and using this list to provide correct medications to patients at the time of hospital admission. Med Rec at admission is the cornerstone of Med Rec during subsequent transfers and at discharge. Med Rec is a major patient safety priority for safety improvement organisations such as the WHO,4 and hospital accreditors.5 Well-designed medication reconciliation programmes can reduce medication discrepancies6 and potential adverse drug events,7 although there are no studies to show a reduction in preventable adverse drug events.

Successful medication reconciliation implementation is a challenge, as evidenced by the Joint Commission's recent decision …