title: Vincristine in childhood leukaemia: no pharmacokinetic rationale for dose reduction in adolescents.
abstract: OBJECTIVE
  To investigate whether there is any pharmacokinetic rationale for the common practice of administering vincristine to adolescents at relatively lower doses than those to younger children.
  
  
  METHODS
  A total of 98 children, aged 1.3-17.3 y, with acute lymphoblastic leukaemia (ALL) were studied on day 1 of induction therapy. Plasma samples were drawn before and 10, 30, 360 and 1380 min after injection of vincristine 2.0 mg/m2 (maximum dose 2.0 mg) and analysed by high-performance liquid chromatography.
  
  
  RESULTS
  The median value (and range) for distribution half-life was 6.4 min (0.8-11.8), elimination half-life 1014 min (258-2570), volume of distribution 445 L/m2 (137-1241) and total body clearance 362 ml/min/m2 (134-2553). No correlation was found between age and any of these pharmacokinetic parameters. The area under the concentration time curve (AUC) was significantly correlated to age (p = 0.002; p - 0.31), as expected from the dosage of vincristine. The lower AUC in children with a body surface area > 1 m2, which is reached at 8-9 y of age, indicates that they received a less intense treatment because of the capping of the vincristine dose at 2.0 mg.
  
  
  CONCLUSIONS
  Vincristine pharmacokinetics were not age dependent in this paediatric population. Thus, we found no pharmacokinetic rationale for dose reduction in adolescents. The common practice of limiting the vincristine dose to 2.0 mg should be carefully reconsidered.
authors.affiliation: Department of Women's and Children's Health, University Children's Hospital, Uppsala, Sweden.
authors.forename: B M
authors.initials: BM
authors.lastname: Frost
authors.forename: G
authors.initials: G
authors.lastname: Lönnerholm
authors.forename: P
authors.initials: P
authors.lastname: Koopmans
authors.forename: J
authors.initials: J
authors.lastname: Abrahamsson
authors.forename: M
authors.initials: M
authors.lastname: Behrendtz
authors.forename: A
authors.initials: A
authors.lastname: Castor
authors.forename: E
authors.initials: E
authors.lastname: Forestier
authors.forename: D R A
authors.initials: DR
authors.lastname: Uges
authors.forename: S S N
authors.initials: SS
authors.lastname: de Graaf
mesh_terms: D000293:Adolescent; D000367:Age Factors; D000972:Antineoplastic Agents, Phytogenic / Q000008:administration & dosage* / Q000493:pharmacokinetics* / Q000627:therapeutic use; D019540:Area Under Curve; D002648:Child; D002675:Child, Preschool; D002851:Chromatography, High Pressure Liquid; D004305:Dose-Response Relationship, Drug; D005260:Female; D006801:Humans; D007223:Infant; D008297:Male; D054198:Precursor Cell Lymphoblastic Leukemia-Lymphoma / Q000188:drug therapy*; D014750:Vincristine / Q000008:administration & dosage* / Q000493:pharmacokinetics* / Q000627:therapeutic use
chemical_list: D000972:Antineoplastic Agents, Phytogenic; D014750:Vincristine