Weight-based dosing of enoxaparin for VTE prophylaxis in morbidly obese, medically-Ill patients.
BACKGROUND
In clinical trials, fixed-dose enoxaparin (40 mg once daily) reduces the risk of venous thromboembolism (VTE) in medically-ill patients. However, morbidly obese patients were under-represented in these trials and using fixed-dose enoxaparin in obese patients may be inadequate. We completed a pharmacokinetic study in morbidly obese, medically-ill patients to determine if weight-based dosing of enoxaparin for VTE prophylaxis was feasible, without excessive levels of anticoagulation, as determined by peak anti-Xa levels.


METHODS
Twenty eight morbidly obese (BMI>or=35 kg/m(2)) patients were enrolled and completed the study protocol. Enoxaparin 0.5 mg/kg was administered once daily subcutaneously and peak anti-Xa levels were measured approximately 4-6 hours after the enoxaparin dose.


CONCLUSIONS
Overall, 46% of patients were female, the average age (+/-SD) was 54 (+/-11) years, and the average weight and BMI were 135.6 kg (+/-25.3) and 48.1 kg/m(2) (+/-11.1), respectively. The average daily dose of enoxaparin was 67 mg (+/-12). The average peak anti-Xa level was 0.25 (SD+/-0.11, range 0.08 to 0.59) units/mL. Peak anti-Xa levels did not significantly correlate with weight or BMI. There were no bleeding events, symptomatic VTE, or significant thrombocytopenia. In morbidly obese, medically-ill patients, use of weight-based enoxaparin dosed at 0.5 mg/kg once daily is feasible and results in peak anti-Xa levels within or near recommended range for thromboprophylaxis, without any evidence of excessive anti-Xa activity. These data suggest that this weight-based regimen may be more effective than standard fixed-dose enoxaparin. Clinical outcome studies are warranted to determine the clinical safety and efficacy of this regimen.
Rondina
Matthew T
MT
Department of Internal Medicine, University of Utah, Salt Lake City, Utah 84132, USA. matthew.rondina@hsc.utah.edu
Wheeler
Michelle
M
Rodgers
George M
GM
Draper
Leslie
L
Pendleton
Robert C
RC
D000328:Adult; D000368:Aged; D000925:Anticoagulants / Q000008:administration & dosage*; D015992:Body Mass Index; D001835:Body Weight; D004334:Drug Administration Schedule; D017984:Enoxaparin / Q000008:administration & dosage*; D005240:Feasibility Studies; D005260:Female; D006801:Humans; D007279:Injections, Subcutaneous; D008297:Male; D008875:Middle Aged; D009767:Obesity, Morbid / Q000188:drug therapy*; D016896:Treatment Outcome; D054556:Venous Thromboembolism / Q000097:blood / Q000517:prevention & control*
D000925:Anticoagulants; D017984:Enoxaparin