title: Age-dependent pharmacokinetics of lansoprazole in neonates and infants.
abstract: BACKGROUND
  Evidence suggests that age may affect the pharmacokinetics of lansoprazole in pediatric patients, but little information is available in neonates and infants.
  
  
  OBJECTIVE
  To determine the pharmacokinetics of lansoprazole in neonates and infants <1 year of age with gastroesophageal reflux disease (GERD)-associated symptoms.
  
  
  METHODS
  Two single- and repeated-dose, randomized, open-label, multicenter studies were conducted. Studies involved a pretreatment period of 7 or 14 days, a dose administration period of 5 days, and a follow-up period of 30 days for adverse events collection. The studies were conducted in both hospital and private clinic settings. The studies were performed in 24 neonates (aged <or=28 days) and 24 infants (aged >28 days, but <1 year) with GERD-associated symptoms diagnosed by medical history and the clinical judgment of the treating physician. Participants received lansoprazole 0.5 or 1.0 mg/kg/day (neonates) or 1.0 or 2.0 mg/kg/day (infants) for 5 days. Plasma pharmacokinetic parameters on dose administration day 1 were calculated, and plasma concentrations on day 5 were obtained.
  
  
  RESULTS
  The pharmacokinetics of lansoprazole were approximately dose proportional. After a single dose in neonates, the mean maximum plasma concentrations (C(max)) were 831 and 1672 ng/mL, and the mean area under the plasma concentration-time curve (AUC) values were 5086 and 9372 ng . h/mL for lansoprazole doses of 0.5 and 1.0 mg/kg, respectively. The time to C(max) (t(max)) [3.1 hours] and harmonic mean terminal elimination half-life (t((1/2))) [2.8 hours] were slightly longer in neonates receiving 0.5 mg/kg than the t(max) (2.6 hours) and t((1/2)) (2.0 hours) values observed in neonates receiving 1.0 mg/kg. Mean oral clearance (CL/F) was identical for the two doses (0.16 L/h/kg). After a single 1.0 or 2.0 mg/kg dose in infants, the lansoprazole C(max) values were 959 and 2087 ng/mL and the mean AUC values were approximately 2203 and 5794 ng . h/mL, respectively. The mean t(max) and mean t((1/2)) were 1.8 hours and 0.8 hours, respectively, for both doses (1.0 or 2.0 mg/kg), while mean CL/F was 0.71 and 0.61 L/h/kg, respectively. In both patient groups, mean plasma concentrations on day 5 were similar to day 1 concentrations. No clinically meaningful accumulation was observed following 5 days' dose administration. Plots of lansoprazole pharmacokinetics against chronologic age showed that dose-normalized C(max), t((1/2)), and AUC were two, three, and five times higher, respectively, in study participants aged <or=10 weeks than in study participants aged >10 weeks-1 year. Lansoprazole was well tolerated in all patients.
  
  
  CONCLUSIONS
  The pharmacokinetics of lansoprazole in pediatric patients are age dependent, with those aged <or=10 weeks showing higher plasma exposure and lower plasma clearance than those aged >10 weeks-1 year. Thus, pediatric patients aged <or=10 weeks require a lower dose of lansoprazole than pediatric patients aged >10 weeks to achieve similar plasma exposure.
authors.affiliation: TAP Pharmaceutical Products Inc, Lake Forest, Illinois, USA.
authors.forename: Weijiang
authors.initials: W
authors.lastname: Zhang
authors.forename: Michael
authors.initials: M
authors.lastname: Kukulka
authors.forename: Galen
authors.initials: G
authors.lastname: Witt
authors.forename: Debra
authors.initials: D
authors.lastname: Sutkowski-Markmann
authors.forename: Janine
authors.initials: J
authors.lastname: North
authors.forename: Stuart
authors.initials: S
authors.lastname: Atkinson
mesh_terms: D053799:2-Pyridinylmethylsulfinylbenzimidazoles / Q000008:administration & dosage / Q000493:pharmacokinetics* / Q000627:therapeutic use; D000367:Age Factors; D000897:Anti-Ulcer Agents / Q000008:administration & dosage / Q000493:pharmacokinetics* / Q000627:therapeutic use; D019540:Area Under Curve; D001189:Aryl Hydrocarbon Hydroxylases / Q000235:genetics / Q000378:metabolism; D065731:Cytochrome P-450 CYP2C19; D004305:Dose-Response Relationship, Drug; D005260:Female; D005764:Gastroesophageal Reflux / Q000188:drug therapy*; D006207:Half-Life; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D064747:Lansoprazole; D008297:Male; D011110:Polymorphism, Genetic
chemical_list: D053799:2-Pyridinylmethylsulfinylbenzimidazoles; D000897:Anti-Ulcer Agents; D064747:Lansoprazole; D001189:Aryl Hydrocarbon Hydroxylases; C045793:CYP2C19 protein, human; D065731:Cytochrome P-450 CYP2C19