Objective: In some medical circumstances, pediatric patients may need premedication for 
transferring to the operating room. In these situations, using intravenous premedication 
is preferred. We assessed the efficacy and safety of intravenous midazolam, intravenous 
ketamine, and combination of both to reduce the anxiety and improve behavior in children 
undergoing general anesthesia.
Methods: In a double‑blind randomized clinical trial, 90 pediatric patients aged 6 months 
to 6 years with American Society of Anesthesiologist grade I or II were enrolled. Before 
anesthesia, children were randomly divided into three groups to receive intravenous 
midazolam 0.1 mg/kg, or intravenous ketamine 1 mg/kg, or combination of half doses 
of both. Behavior types and sedation scores were recorded before premedication, after 
premedication, before anesthesia, and after anesthesia in the postanesthesia care unit. 
Anesthesia time, recovery duration, blood pressure, and heart rate were also recorded. For 
comparing distribution of behavior types and sedation scores among three groups, we used 
Kruskal–Wallis test, and for comparing mean and standard deviation of blood pressure and 
heart rates, we used analysis of variance.
Findings: After premedication, children’s behavior was significantly better in the combination 
group (P < 0.001). After anesthesia, behavior type was same among three groups (P = 0.421). 
Sedation scores among three groups were also different after premedication and the 
combination group was significantly more sedated than the other two groups (P < 0.001).
Conclusion: Combination of 0.05 mg/kg of intravenous midazolam and 0.5 mg/kg of 
intravenous ketamine as premedication produced more deep sedation and more desirable 
behavior in children compared with each midazolam 0.1 mg/kg or ketamine 1 mg/kg.