Pharmacokinetics of midazolam in critically ill pediatric patients

Midazolam is frequently used to produce sedation in critically ill pediatri c patients. We studied the pharmacokinetics of midazolam in 22 patients (ag e 8 days to 16 years). The intravenous infusion rate to produce sedation ra nged from 49-385 mcg/kg/hr. The blood samples were obtained at steady - state and midazolam was measure d by gas chromatography with electron capture. The steady - state plasma co ncentrations of midazolam ranged from 49-385 ng/mL. The total clearance, ap parent volume of distribution, and elimination half - life ranged from 0.1- 3.1 L/kg/hr, 0.2-3.5 L/kg, and 0.3-10.9 hours, respectively. The marked int erpatient variability in pharmacokinetics explains in part, the substantial variation in dosage requirements of midazolam to produce sedation in criti cally ill pediatric patients.