Use of methadone for opioid weaning in children: prescribing practices and trends.

Critically ill children are routinely treated with opioids to relieve pain, produce sedation, increase cooperation, and reduce metabolic demands. However, prolonged exposure to opioids followed by abrupt cessation frequently leads to opioid withdrawal syndrome. This syndrome is present in 35% to 57% of children who have received fentanyl by continuous infusion. It is characterized by a hyperadrenergic response following the abrupt reduction in opioid dosage, with clinical symptoms that include irritability, tremors, twitching, gastrointestinal disturbances, hypertension, and fever. The dose and duration of opioid use influence the development of opioid withdrawal symptoms. However, proper pharmacologic management of withdrawal is still controversial, and there is little evidence upon which to base recommendations regarding prevention, assessment, and management of withdrawal in critically ill children. Opioid weaning protocols aim to gradually decrease plasma concentrations of the drug to prevent symptoms of opioid withdrawal syndrome. Oral morphine, methadone, and clonidine and transdermal fentanyl have all been used in opioid weaning programs, but methadone is often the most suitable, because of the convenience of oral dosing and the long half-life. Currently, there is great variability among recommended methadone weaning protocols to prevent withdrawal symptoms in the pediatric population. Some factors that may influence the methadone dosing schedule are initial diagnosis; duration of opioid therapy; patient’s age, developmental stage, and sex; and interacting concomitant medications. At the time of the current study, methadone prescription protocols at the authors’ institution were designed on a case-bycase basis. The authors believed that standardization of opioid weaning protocols would result in safer dosing schedules, fewer cases of withdrawal symptoms, and shorter hospital stays. The objectives of this study were to describe weaning practices in a hospital where weaning was done on a case-bycase basis, without standardized protocols; to determine whether there were common patterns for methadone-weaning practices shown to be effective; and to quantify and characterize any patterns found.