The injection rate of intravenous midazolam significantly influences the occurrence of paradoxical reaction in pediatric patients

BACKGROUND Paradoxical reactions to benzodiazepines including restlessness, anxiety and sometimes violent behavior sometimes occur. Most of the known predicting factors of disinhibitory reactions such as age, gender, genetic or the psychological background are not modifiable. This study was conducted to evaluate the effect of rate of midazolam administration, as a controllable factor, on the occurrence of paradoxical reaction to midazolam (PRM) in pediatric patients. MATERIALS AND METHODS In a randomized, double-blind clinical trial 98 American Society of Anesthesiologists physical status I, II, aged from 6 months to 6 years, and undergoing elective surgery, were enrolled in the study. Patients were randomly allocated to receive midazolam 0.1 mg/kg as a 0.1% solution at an injection rate of 0.2 ml/s or 1 ml/s. The occurrence of PRM was compared between the two groups with Chi-square test. RESULTS The occurrence of PRM in the rapid injection group was significantly higher than the slow injection group (20.4% vs. 4.1%, P < 0.05, relative risk CI: 95% 6.03 (1.24-29.4)). CONCLUSION Slow intravenous administration of midazolam significantly reduces the occurrence of paradoxical reactions and should be respected in premedication of pediatric patients.