Many medications remain at risk for producing an adverse drug event (ADE) despite proper ordering and administration. This study examined more than 4300 ADEs to determine potential risk factors, such as specific patient characteristics. Using a logistic regression model, investigators discovered several risk factors that were present across drug classes with others that remained class-specific. For instance, drug administration route represented a significant risk factor for all ADEs. The article includes detailed tables outlining ADEs captured and risk factors by drug category. The authors conclude that high-risk drugs, as well as high-risk patient and drug administration characteristics, should be vigilantly monitored.