Iodixanol Pharmacokinetics in Children

Abstract

The objective of this report was to study the elimination pharmacokinetics of iodixanol in children. Iodixanol (V isipaque ®, Nycomed Inc., Wayne, PA, USA) is a new iso-osmolar iodinated radiocontrast agent. We hypothesized that elimination of this agent would be dependent on age-related differences in renal clearance. Seven centers enrolled 43 patients. Cardiac catheterization was performed in 41 patients and cranial computed tomography in 2. Patients were entered into 5 age groups: newborn to <2 months, 2 to <6 months, 6 months to <1 year, 1 to <3 years, and 3 to ≤12 years. Plasma samples were obtained before and at 4 time periods after completion of iodixanol injection: 0.75–1.25 hours, 2–4 hours, 8–12 hours, and 16–32 hours. Plasma concentrations of iodixanol were determined using high performance liquid chromatography. The primary pharmacokinetic endpoint was the terminal elimination rate constant ( k el ). Data were complete for 40 patients, showing mean k el significantly lower in newborn to <2-month-old patients vs older patients: (h −1 , mean ± standard deviation [SD]): newborn to <2 months 0.185 ± 0.060, 2 to <6 months, 0.256 ± 0.046, 6 months to <1 year 0.299 ± 0.042, 1 to <3 years 0.322 ± 0.058, and 3 to ≤12 years 0.307 ± 0.071; with increasing age, excretion is more rapid, as shown by each age group's elimination half-life ( t 1/2 β) (h) 4.14 ± 1.41, 2.79 ± 0.55, 2.36 ± 0.37, 2.23 ± 0.51, and 2.36 ± 0.52, respectively. Iodixanol has elimination in children >6 months of age that is comparable to normal adults. Prolonged elimination in children <6 months of age is related to renal immaturity.