This systematic review analyzed five studies discussing adverse events due to medical errors involving high-alert medications. The authors estimated the pooled prevalence at 16.3%, but the included studies reported a wide variation in prevalence (from 3.8% to 100%). The studies also reported a wide range in error severity – up to 19.2% were considered moderate, up to 15.4% were considered serious, and up to 1.9% were considered lethal. The most common medication administration errors involved insulin, potassium chloride, and epoprostenol.