Intrathecal Methotrexate Containing the Preservative Benzyl Alcohol Erroneously Administered in Pediatric Leukemia Patients: Clinical Course and Preventive Process

Administration of intrathecal chemotherapy for leukemia is a common procedure in pediatric oncology. The direct delivery of drug into the cerebral spinal fluid requires that no preservative be used. Preserved drugs administered in error can result in significant neurotoxicity. A case series is described where preservative-containing methotrexate was incidentally administered intrathecally. All patients were treated at Children's Hospitals and Clinics of Minnesota. Medical records of the patients affected were reviewed and abstracted for this report. Four children with acute lymphoblastic leukemia received 1 dose of intrathecal methotrexate that contained 0.07% benzyl alcohol in January 2019. Overall, minimal to no symptoms were seen after dosing. The error was traced to a drug shortage in which benzyl alcohol-containing methotrexate was obtained and incorrectly stocked. A novel replacement drug procurement process was developed within our institution. The process includes sequestered queues where a drug awaits evaluation and independent double check of entry accuracy in the electronic health record and pharmacy parenteral dose preparation software prior to release and use. In contrast to IV administration, intrathecal benzyl alcohol at concentrations ≥ 0.9% can cause significant neurotoxicity. Although minimal, if any, neurotoxicity was seen in patients who received a 10-fold lower concentration of benzyl alcohol than previously associated with complications, all institutions should recognize the potential for this error and implement similar safety precautions to ensure that this type of error will not occur.