Purpose: Domperidone is used in Canada as a motility and antiemetic agent. Inappropriate use is of particular concern because of its associated risks of life-threatening ventricular arrhythmias and sudden cardiac death. This study aimed to assess the impact of a Health Canada advisory in 2012 on domperidone prescription patterns. Methods: A retrospective chart review was conducted for consecutive patients at two tertiary care sites prescribed domperidone before and after the Health Canada advisory during quarters in 2005 and 2012, respectively. Study patients included those prescribed domperidone during hospital and those with preexisting prescriptions. The main outcome assessed was appropriateness of domperidone prescription based on: 1) Health Canada-approved indications, 2) dosing regimens, and 3) pre-treatment assessment, including measurement of serum potassium (K+), magnesium (Mg+) and calcium (Ca2+) levels, performance of baseline ECG, monitoring of QTc intervals and left ventricular (LV) dysfunction, and co-prescription of other QT-prolonging medications. Differences in outcomes between 2005 and 2012 were evaluated by univariable and multivariable analyses. Results: A total of 577 patients were included: 290 in 2005 (mean age 62.4) and 287 in 2012 (mean age 67.9). Compared to 2005 (prior to the Health Canada advisory), significantly less domperidone was initiated in hospital (71.4% vs. 39.4%, p<0.0001), or was prescribed for non-approved indications (84.8% vs. 58.2%, p<0.0001) or at inappropriate doses >30 mg/day (65.5% vs. 47.4%, P<0.0001) in 2012 (after the Health Canada advisory). In a multivariable model, in-hospital initiation (OR 7.01, 95% CI 4.52-10.87, p<0.0001) and domperidone use as a sole GI drug (OR 2.51, 95% CI 1.38-4.55, p=0.002) predicted prescription with non-approved indications. Basic cardiac risk assessment and the performance of baseline laboratory tests were not routinely done prior to initiation of domperidone, although there was improvement in 2012 compared to 2005 (Table 1).Table 1: Assessment prior to domperidone initiation during hospitalization—2005 vs. 2012Conclusion: There has been more appropriate use of domperidone following the Health Canada warning. Yet, inappropriate utilization and inadequate pre-treatment assessment remain common. Increased awareness of domperidone's indications and adverse effects could serve to reduce inappropriate prescription and thereby improve patient safety and reduce cost.