Inaccurate medication reconciliation leads to medication discrepancies and places patients at risk for adverse drug events. Health information exchange can enhance medication safety through improved access to prescribing information. In this cluster-randomized trial, a pharmacist performed medication reconciliation with access to a regional health information exchange for patients admitted to a single hospital in the intervention arm and without such information access for patients in the control arm. In the first 10 months of the study, the health information exchange provided access to prescribing information from large hospitals and a pharmacy insurance plan, but only hospital prescribing information was available during the last 21 months because the insurance plan began charging for data. Although researchers found no significant difference between the intervention and control groups with regard to the number of medication discrepancies, patients who underwent medication reconciliation with access to pharmacy insurance data had a higher number of medication discrepancies identified than control patients. They conclude that charging for pharmacy data interrupted the positive effect of health information exchange on medication reconciliation in the study. A past WebM&M commentary described how lack of access to prescribing information led to an adverse drug event.