title: Phamacokinetics of rivaroxaban in adolescents.
abstract: BACKGROUND
  The direct factor Xa inhibitor rivaroxaban is approved for venous thromboembolism (VTE) treatment in adults. However, in all phase-III trials children or adolescents have not been included. For under-aged VTE patients, current standard treatment consists of low molecular weight heparin or Vitamin K antagonists. Rivaroxaban could be an attractive alternative, however, no data on the pharmacokinetics (PK) of rivaroxaban in adolescents are currently available. PATIENT, METHODS: We report PK data for rivaroxaban derived from a girl (age:15 years), who presented three month after acute deep vein thrombosis, already receiving rivaroxaban therapy. In the steady state of rivaroxaban therapy (20 mg once daily), plasma levels at baseline, 3 and 6 hours after intake of rivaroxaban were measured to evaluate the pharmacokinetics and changes of global coagulation tests.
  
  
  RESULTS
  At baseline, a very low trough level of only 9.9 ng/ml rivaroxaban was found. At 3 hours, a peak concentration of 137.76 ng/ml rivaroxaban was observed with a rapid decrease within 6 hours after drug intake, when plasma levels of 34.45 ng/ml were measured. The patients INR and aPTT values reacted correspondingly.
  
  
  CONCLUSIONS
  Our data indicate that adolescents may exhibit lower peak and trough levels after rivaroxaban intake compared to adult patients, but seem to have similar PK curves during the elimination phase. While our case is the first published case of a successful VTE treatment in an under-aged patient, we strongly discourage the routine use of rivaroxaban in non-adult patients, until data from phase II and III trials are available.
authors.affiliation: Priv.-Doz. Dr. med. Jan Beyer-Westendorf, Center for Vascular Diseases and Medical Clinic III, University Hospital Carl Gustav Carus, Fetscherstraße 74, 01307 Dresden, Germany, Tel. +49/(0)351/458 22 36; Fax +49/(0)351/458 58 09, E-mail: jan.beyer@uniklinikum-dresden.de.
authors.forename: J
authors.initials: J
authors.lastname: Beyer-Westendorf
authors.forename: S
authors.initials: S
authors.lastname: Gehrisch
mesh_terms: D000293:Adolescent; D065427:Factor Xa Inhibitors / Q000008:administration & dosage; D005260:Female; D005343:Fibrinolytic Agents / Q000008:administration & dosage / Q000493:pharmacokinetics; D006801:Humans; D008657:Metabolic Clearance Rate; D009025:Morpholines / Q000008:administration & dosage* / Q000493:pharmacokinetics*; D000069552:Rivaroxaban; D013876:Thiophenes / Q000008:administration & dosage* / Q000493:pharmacokinetics*; D020246:Venous Thrombosis / Q000097:blood* / Q000188:drug therapy*
chemical_list: D065427:Factor Xa Inhibitors; D005343:Fibrinolytic Agents; D009025:Morpholines; D013876:Thiophenes; D000069552:Rivaroxaban
keywords: Rivaroxaban; adolescents; pharmacokinetics