Adverse Events Related to Lorazepam Use on Medical Floors

Abstract

Background: Lorazepam, an intermediate-acting benzodiazepine, is associated with oversedation and respiratory depression. Objectives: To evaluate lorazepam use and related adverse drug events (ADEs) on medical floors and to identify possible risk factors for ADEs among the lorazepam recipients. Methods: A retrospective evaluation at an academic medical center was performed on patients admitted to medical floors who received lorazepam during the years 2004-2005. It examined use trends for lorazepam and compared the risk factors between lorazepam-related ADEs (ADE patients) and patients receiving lorazepam who did not experience an ADE related to this agent (non-ADE patients). Results: Lorazepam was prescribed to 7.3% of patients admitted to medical floors over the 2-year study period. Fourteen patients experienced oversedation related to lorazepam administration, and 5 (35.7%) of these patients also experienced respiratory depression. The ADE rate was 5.5/10,000 doses. Patients experiencing ADEs received higher mean daily doses compared with non-ADE patients (2.7 mg versus 1.7 mg; P = 0.001). Eleven (78.6%) ADE patients received lorazepam parenterally. All 14 ADE patients were concomitantly administered sedating medications. Additionally, ADE patients were found to have lower albumin levels compared with non-ADE patients (2.1 g/dL versus 2.8 g/dL; P = 0.001). Preexisting severe liver disease was more common in ADE patients (21%) compared with non-ADE patients (4.8%) (P = 0.004). Conclusions: Lorazepam should be used with caution on medical floors. Patients receiving parenteral lorazepam and/or doses greater than 2.5 mg daily are at higher risk of developing ADEs. Concomitant administration of sedating medications, low serum albumin level and preexisting liver disease may increase this risk.