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 t hat elimination of this agent would be dependent on age-related differences in renal clearance. Seven centers enrolled 43 patients. Cardiac catheteriz ation was performed in 41 patients and cranial computed tomography in 2. Pa tients 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 yea rs. Plasma samples were obtained before and at 4 time periods after complet ion 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 per formance liquid chromatography. The primary pharmacokinetic endpoint was th e terminal elimination rate constant (k(el)). Data were complete for 40 pat ients, showing mean k(el) significantly lower in newborn to <2-month-old pa tients vs older patients: (h(-1), mean +/- standard deviation [SD]): newbor n to <2 months 0.185 +/- 0.060, 2 to <6 months, 0.256 +/- 0.046, 6 months t o <1 year 0.299 +/- 0.042, 1 to <3 years 0.322 +/- 0.058, and 3 to <less th an 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.