Study objective: Despite widespread use of adjunctive benzodiazepines during ketamine sedation, their efficacy in reducing recovery agitation in children has never been studied. We wished to characterize the nature and severity of recovery agitation after ketamine sedation in children treated in the emergency department and to determine whether the addition of adjunctive midazolam reduces the magnitude of such recovery agitation. Methods: The study was a randomized, double-blind, clinical trial of adjunctive midazolam versus placebo during ketamine sedation. We enrolled 104 children aged 12 months to 15 years (median age, 6 years) at a combined university medical center and children’s hospital. Subjects received either intravenous midazolam (0.05 mg/kg up to 2 mg) or placebo after intravenous administration of a ketamine loading dose (1.5 mg/kg). Treating physicians and nurses independently noted the presence of crying, hallucinations, and nightmares during recovery and graded recovery agitation by using a 100-mm visual analog scale. Preprocedure agitation and external stimulation during recovery were also graded. The time from ketamine injection until each subject met the recovery criteria was recorded. Results: Fifty-three subjects received midazolam, and 51 received placebo. Potentially confounding variables were similar between the groups. Sedation efficacy, adverse effects, and recovery time were also similar between groups. Interobserver agreement between physician and nurse assessments was substantial. Median physician assessment of recovery agitation was 4 mm (interquartile range, 2 to 19) in the midazolam group and 5 mm (interquartile range, 3 to 14) in the placebo group (difference –1; 95% confidence interval –3 to 2; P =.705). Recovery agitation was moderately correlated with preprocedure agitation (ρ=0.486) but not with external stimulation during recovery (ρ=0.147). Conclusion: Recovery agitation is common but generally of very low magnitude after ketamine sedation in children in the ED. We observed a median physician rating of 5 mm on a 100-mm visual analog scale, a score that we believe to be clinically insignificant. The degree of recovery agitation after ketamine sedation is significantly related to the degree of preprocedure agitation. In this study, concurrent midazolam did not diminish such agitation and had no measurably beneficial effect. Use of adjunctive benzodiazepines in pediatric ketamine sedation appears unnecessary. [Sherwin TS, Green SM, Khan A, Chapman DS, Dannenberg B. Does adjunctive midazolam reduce recovery agitation after ketamine sedation for pediatric procedures? A randomized, double-blind, placebo-controlled trial. Ann Emerg Med .March 2000;35:229-238.]