title: Incidence of deep vein thrombosis is increased with 30 mg twice daily dosing of enoxaparin compared with 40 mg daily.
abstract: BACKGROUND
  The purpose of this study was to analyze whether 2 standard dosing regimens of enoxaparin (30 mg twice daily vs 40 mg once daily) would result in different deep vein thrombosis (DVT) rates and anti-factor Xa activity (anti-Xa) in surgical patients.
  
  
  METHODS
  Patients who required enoxaparin for prophylaxis were followed prospectively. Demographics were recorded. Patients underwent standardized duplex screening. Peak anti-Xa levels were drawn on 4 consecutive days.
  
  
  RESULTS
  Sixty-three patients were followed up (28 patients on 30 mg twice daily, 35 patients on 40 mg once daily). There was no significant difference in demographics between groups. Twenty-five percent of patients on 30 mg twice daily developed a DVT, whereas 2.9% of patients on 40 mg once daily developed a DVT. Patients on 30 mg twice daily had significantly lower anti-Xa levels.
  
  
  CONCLUSIONS
  The incidence of DVT is increased in surgical patients who receive 30 mg twice daily dosing of enoxaparin compared with 40 mg daily. Dosing of 40 mg once daily results in significantly higher peak anti-Xa levels compared with 30 mg twice daily.
authors.affiliation: Division of Trauma, Critical Care, and Acute Care Surgery, Oregon Health & Science University, 3181 SW Sam Jackson Park Rd, Mail Code L-611, Portland, OR 97239-3098, USA. Electronic address: rihag@ohsu.edu.
authors.forename: Gordon M
authors.initials: GM
authors.lastname: Riha
authors.affiliation: Division of Trauma, Critical Care, and Acute Care Surgery, Oregon Health & Science University, 3181 SW Sam Jackson Park Rd, Mail Code L-611, Portland, OR 97239-3098, USA.
authors.forename: Philbert Y
authors.initials: PY
authors.lastname: Van
authors.affiliation: Division of Trauma, Critical Care, and Acute Care Surgery, Oregon Health & Science University, 3181 SW Sam Jackson Park Rd, Mail Code L-611, Portland, OR 97239-3098, USA.
authors.forename: Jerome A
authors.initials: JA
authors.lastname: Differding
authors.affiliation: Division of Trauma, Critical Care, and Acute Care Surgery, Oregon Health & Science University, 3181 SW Sam Jackson Park Rd, Mail Code L-611, Portland, OR 97239-3098, USA.
authors.forename: Martin A
authors.initials: MA
authors.lastname: Schreiber
authors.affiliation: Division of Trauma, Critical Care, and Acute Care Surgery, Oregon Health & Science University, 3181 SW Sam Jackson Park Rd, Mail Code L-611, Portland, OR 97239-3098, USA.
mesh_terms: D000925:Anticoagulants / Q000008:administration & dosage*; D004334:Drug Administration Schedule; D017984:Enoxaparin / Q000008:administration & dosage*; D015951:Factor Xa / Q000187:drug effects; D005260:Female; D006801:Humans; D015994:Incidence; D008297:Male; D008875:Middle Aged; D011446:Prospective Studies; D020246:Venous Thrombosis / Q000453:epidemiology* / Q000517:prevention & control*
chemical_list: D000925:Anticoagulants; D017984:Enoxaparin; D015951:Factor Xa