title: Preemptive dosage reduction of nadroparin in patients with renal failure: a retrospective case series.
abstract: BACKGROUND
  Low-molecular-weight heparins (LMWHs) are frequently used to treat arterial and venous thrombo-embolic events. LMWHs accumulate with renal failure, but only limited clinical data regarding appropriate dosage adjustments are available. Nevertheless, LMWHs are routinely used in these patients worldwide. Although many clinics apply renal function-based dosage reductions, anti-factor Xa (anti-Xa) activity is not measured routinely.
  
  
  METHODS
  We determined anti-Xa activity in 51 patients with MDRD-eGFR <60 mL/min/1.73 m(2), treated with therapeutic doses of nadroparin according to a standard, renal function-based guideline.
  
  
  RESULTS
  An a priori dosage reduction resulted in anti-Xa activity within, below and above the reference range in 51, 30 and 19% of the measurements, respectively. Treatment resulted in different anti-Xa activities compared with dosages that were not given according to official advice (P < 0.001). Anti-Xa values increased with longer treatment duration (P = 0.038).
  
  
  CONCLUSIONS
  A preemptive fixed reduction (25%) of the nadroparin dosage in all patients with renal failure seems appropriate. However, because target anti-Xa activities were reached in only half of the patients, we submit that the use of nadroparin, dosage reduction and monitoring of anti-Xa activity in combination with clinical outcome monitoring in this patient population urgently needs further investigation.
authors.affiliation: Department of Hospital Pharmacy , Meander Medical Centre , Amersfoort , The Netherlands.
authors.forename: Marije
authors.initials: M
authors.lastname: Russcher
authors.affiliation: Department of Internal Medicine , University Medical Centre Utrecht , Utrecht , The Netherlands.
authors.forename: Nienke
authors.initials: N
authors.lastname: Josephus Jitta
authors.affiliation: Department of Clinical Chemistry and Laboratory Medicine , Meander Medical Centre , Amersfoort , The Netherlands.
authors.forename: Rob J
authors.initials: RJ
authors.lastname: Kraaijenhagen
authors.affiliation: Department of Internal Medicine , Meander Medical Centre , Amersfoort , The Netherlands.
authors.forename: Rob
authors.initials: R
authors.lastname: Fijnheer
authors.affiliation: Meander Academy , Meander Medical Centre , Amersfoort , The Netherlands.
authors.forename: Pieternel C M
authors.initials: PC
authors.lastname: Pasker-de Jong
authors.affiliation: Department of Internal Medicine , Meander Medical Centre , Amersfoort , The Netherlands.
authors.forename: Carlo A J M
authors.initials: CA
authors.lastname: Gaillard
keywords: anti-factor Xa activity; nadroparin; renal failure