OBJECTIVES: Specialised hospital pharmacists, integrated in medical teams on the ward, can improve medication safety. When a specialised hospital pharmacist is temporarily not available, the pharmaceutical care will be conducted by a substitute hospital pharmacist with less specific knowledge about that patient population. Our objective was to compare the resolution rate of prescribing errors between specialised hospital pharmacists and their substitutes. Furthermore, we investigated whether other characteristics of the pharmacists, the prescriber, patient, drug or intervention itself were associated with the resolution rate. METHODS: A retrospective cross-sectional study was conducted to assess the resolution of prescribing errors, based on the analysis of electronic prescriptions. A prescribing error was defined as an alert that required intervention of the pharmacist to prevent harm or to optimise therapy. To identify prescribing errors, a medical doctor and hospital pharmacist analysed all alerts that were retained to be checked by a pharmacist. Resolution of a prescribing error was defined as resolution of the error within 24 hours after detection. RESULTS: In total, 145 574 medication prescriptions were analysed and 448 prescribing errors were detected. Of these prescribing errors, 94.0% were resolved within 24 hours. No differences were found between the resolution rate of prescribing errors after advice from a specialised hospital pharmacists and their substitutes (94.4% vs 91.9%, p=0145 (χ CONCLUSIONS: In the temporarily absence of a specialised hospital pharmacist, the resolution rate of prescribing errors remains high when advice about prescribing errors is provided by a substitute hospital pharmacist.