Iodixanol pharmacokinetics in children

The objective of this report was to study the elimination pharmacokinetics of iodixanol in children. Iodixanol (VISIPAQUE(R), 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 less than or equal 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 <less than or equal 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) beta) (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.