Implementation of an enoxaparin protocol for venous thromboembolism prophylaxis in obese surgical intensive care unit patients

Ann Pharmacother. 2011 Nov;45(11):1356-62. doi: 10.1345/aph.1Q313. Epub 2011 Oct 18.


Background: Venous thromboembolism (VTE) is a serious health care issue that affects a large number of people. Few standards exist for delineating the optimal dosing strategy for VTE prevention in obese patients, especially in the setting of major surgery or trauma.

Objective: To document the efficacy of a surgical intensive care unit (SICU)-specific, weight-based dosing protocol of enoxaparin 0.5 mg/kg given subcutaneously every 12 hours for VTE prophylaxis in morbidly obese (defined as body mass index [BMI] ≥35 kg/m(2) or weight ≥150 kg) SICU patients, using peak anti-factor Xa levels to determine therapeutic endpoints.

Methods: Data were collected retrospectively in an academic, university-based SICU on 23 morbidly obese patients who received weight-based enoxaparin for VTE prophylaxis from December 1, 2008, through June 30, 2010.

Results: A weight-based dosage range of enoxaparin 50-120 mg twice daily (median 60) was given to 23 patients. The mean BMI was 46.4 kg/m(2). The initial mean anti-factor Xa level (measured after the third dose) was 0.34 IU/mL (range 0.20-0.59). Patients received an average of 18 doses. Two cases required an increase or decrease in dosage based on anti-factor Xa levels. Morbidity related to this dosing included a single event of minor endotracheal bleeding and a single deep vein thrombosis that was likely present prior to treatment.

Conclusions: Weight-based dosing with enoxaparin in morbidly obese SICU patients was effective in achieving anti-factor Xa levels within the appropriate prophylactic range. This regimen reduced the rate of VTE below expected levels and no additional adverse effects were reported.

MeSH terms

  • Adolescent
  • Adult
  • Aged
  • Anticoagulants / administration & dosage*
  • Anticoagulants / adverse effects
  • Body Mass Index
  • Drug Administration Schedule
  • Enoxaparin / administration & dosage*
  • Enoxaparin / adverse effects
  • Female
  • Hemorrhage / drug therapy
  • Hemorrhage / prevention & control
  • Humans
  • Intensive Care Units
  • Male
  • Middle Aged
  • Obesity, Morbid / blood
  • Obesity, Morbid / complications*
  • Obesity, Morbid / surgery*
  • Retrospective Studies
  • Venous Thromboembolism / complications*
  • Venous Thromboembolism / drug therapy
  • Venous Thromboembolism / prevention & control
  • Venous Thromboembolism / therapy*
  • Young Adult


  • Anticoagulants
  • Enoxaparin