The effective dose of ketamine in the management of acute agitation in emergency departments

Ketamine therapy is considered a novel treatment for agitation. Ketamine has a rapid onset and short half-life, can be administered in various formulations, and delivers sedation reliably with a single dose. However, providing a well-defined dose of ketamine for acute agitation, particularly as an intravenous (IV) bolus, is questionable. This study aims to define an effective dose of ketamine for treating acute agitation in the emergency department (ED). A multi-center retrospective observational study was conducted from June 2015 to March 2022 to examine agitated patients presented to four EDs in Saudi Arabia and were administered ketamine as the initial calming medication. The study included a total of 20 patients, most of whom were males (70%) in their adult ages (65%) who were mainly presented to the ED with behavioral, cognitive or psychiatric disorders (55%). Only six patients (28.6%) needed an additional calming agent. The 50 mg IV bolus was the most common initial (n = 6) and cumulative (n = 5) fixed dose and achieved a success rate of 66.7% in both doses. The most common initial weight-based dose was 0.5 mg/kg in 7 cases (71.4% success rate), followed by 0.7-0.8 mg/kg in 6 cases (66.7% success rate). Meanwhile, the doses 0.5 mg/kg in 6 cases (83.3% success rate) and 0.7-0.8 mg/kg in 6 cases (66.7% success rate) were major cumulative weightbased doses. The results were interpreted using descriptive statistics. Overall, ketamine showed neutral effects on the respiratory and cardiac markers. It is seldom used as an initial medication for acute agitation in the ED. A starting dose of 0.5-1 mg/kg or 50 mg of ketamine as an IV bolus injection showed reasonable effectiveness and appropriate safe properties in calming agitated patients in the ED.