The aim of this study was to identify the optimal rates at which opioids and benzodiazepines should be weaned in order to prevent withdrawal reactions in the pediatric intensive care unit (PICU). This study follows an earlier investigation that developed a graphical analysis method for examining behavioral signs of withdrawal in relation to changes in opioid and benzodiazepine administration. This method was utilized in this present study for a prospective sample of all patients admitted to a tertiary/quaternary level PICU within a 4-week interval (n=27). The findings of this study indicate that the required rate of weaning (in order to prevent withdrawal reactions) is related to the number of days the child has been on a continuous infusion of opioids and/or benzodiazepines. Adverse withdrawal reactions were prevented when the daily rate of weaning did not exceed: 20% for children receiving continuous infusions for 1-3 days; 13-20% for 4-7 days; 8-13% for 8-14 days; 8% for 15-21 days; and 2-4% for more than 21 days of infusions. The authors recommend that the rate of weaning of opioids and benzodiazepines in critically ill children be tailored to the length of time the child received continuous infusions of these agents.