Extended Sedation With Continuous Midazolam or Dexmedetomidine Infusion for Young Children Receiving 131I-MIBG Radiopharmaceutical Therapy for Advanced Neuroblastoma

Background(131)I-MIBG is increasingly used for treating neuroblastoma; however, administration requires careful adherence to radiation safety guidelines. We describe our experience using continuous sedation to facilitate safe I-131-MIBG therapy for young children. ProcedurePatients were included in this case series if they received continuous midazolam or dexmedetomidine infusion for sedation during I-131-MIBG therapy from November 1, 2012, to October 1, 2014. Key outcomes included adequacy of sedation for both I-131-MIBG infusion and the duration of radioactive isolation, as well as sedative-related toxicities. Additionally, nuclear medicine scans before and after I-131-MIBG therapy were assessed using the Curie score. These scores were compared qualitatively between midazolam, dexmedetomidine, and control (no sedative infusion) groups. ResultsOf the 13 patients receiving continuous sedation for I-131-MIBG therapy, seven achieved adequate sedation with midazolam, five achieved adequate sedation with dexmedetomidine, one patient (1.6 years old) failed to achieve adequate sedation with either medication and did not receive I-131-MIBG therapy. Sedation was generally well tolerated. Common side effects for dexmedetomidine infusion included hypotension and relative bradycardia. Both treatment and control groups had multiple patients with increased Curie scores post-I-131-MIBG therapy. However, one patient in the midazolam group and two in the dexmedetomidine group had decreased Curie scores after I-131-MIBG therapy, while none decreased in the control group. ConclusionsAlthough we cannot exclude the possibility of some inhibition of I-131-MIBG uptake by midazolam or dexmedetomidine, this case series suggests that continuous infusions of either agent can provide effective sedation to allow safe administration of I-131-MIBG to young patients.