A prospective analysis of intramuscular meperidine, promethazine, and chlorpromazine in pediatric emergency department patients.
 STUDY OBJECTIVE: To examine physiologic responses and efficacy of 2, 1, and 1 mg/kg IM meperidine, promethazine, and chlorpromazine (MPC), respectively, in children.
 DESIGN: Prospective, unblinded trial.
 SETTING: A university and community emergency department.
 PATIENTS: Sixty-three hemodynamically and neurologically stable children.
 INTERVENTION: Single dose of IM MPC.
 MEASUREMENTS AND MAIN RESULTS: Serial respirations, heart rate, arterial systolic blood pressure, oxygen saturation, and Glasgow Coma Scale were measured at 30-minute intervals.
 Effectiveness was assessed by two independent observers using separate visual analog scales for cooperation and sedation.
 Times to sleep (27 +/- 24 minutes), sitting upright (103 +/- 87 minutes), ED discharge (4.7 +/- 2.4 hours), eating (11 +/- 7.9 hours), and normal behavior (19 +/- 15 hours) were acceptable.
 Minor, but statistically significant, changes in respiration rate (-1.9 +/- 0.4), heart rate (+4.5 +/- 1.8), oxygen saturation (-0.7 +/- 0.3%), and Glasgow Coma Scale (-2.5 +/- 0.6) occurred for 120 minutes after MPC.
 No serious complications or resuscitation were required.
 Mean visual analog scale scores were 5.0/10.4 or more in 71% of cases, with interobserver agreement very good (cooperation, r = .79; effectiveness, r = .80).
 Twenty-nine percent of children were judged insufficiently sedated.
 CONCLUSION: IM MPC is a safe and generally effective agent for ED procedures in selected children.
