Reversible neurologic abnormalities associated with prolonged intravenous midazolam and fentanyl administration.

An encephalopathy developed in three infants in the intensive care unit after heavy sedation with midazolam and fentanyl for 4 to 11 days. The affected infants had poor social interaction, decreased visual attentiveness, dystonic postures, and choreoathetosis. Symptoms cleared completely in 5 days to 4 weeks. Retrospective review of records of all children treated in the intensive care unit with prolonged intravenous administration of midazolam revealed that 45 children could be assessed neurologically on withdrawal of sedation. Three children had definite and two had possible neurologic sequelae (5/45, 11.1%). All had received concomitant intravenous fentanyl therapy. Neurologic sequelae were significantly associated with young age, female gender, low serum albumin concentration, and concomitant administration of aminophylline. This encephalopathy may represent a benzodiazepine withdrawal syndrome, a prolonged agonist action on the benzodiazepine receptor, or the combined effects of multiple toxic, metabolic, and infectious insults to the central nervous system of infants in the intensive care unit. Prolonged use of intravenous midazolam sedation necessitates careful dosing, monitoring, and discontinuation, particularly in infants and young children.