Clinical Drug Investigation

, Volume 40, Issue 1, pp 33–40 | Cite as

Stratifying Therapeutic Enoxaparin Dose in Morbidly Obese Patients by BMI Class: A Retrospective Cohort Study

  • Young R. LeeEmail author
  • Peter J. Palmere
  • Caitlin E. Burton
  • Taylor M. Benavides
Original Research Article



Enoxaparin is a low-molecular weight heparin (LMWH) commonly used for treatment of venous thromboembolism and acute coronary syndromes. The recommended dose for these conditions is weight-based (1 mg/kg) and doesn’t require dose-capping. However, previous studies have shown that in those with a body mass index (BMI) > 40 kg/m2, this dose results in supratherapeutic levels.


This study investigated enoxaparin dosing in morbidly obese patients with a goal of identifying a dose with the greatest chance of producing favorable anti-factor Xa (anti-Xa) levels.


This retrospective cohort study by electronic chart review was used to record data of patients who received enoxaparin with anti-Xa level monitoring between 2012 and 2017. The primary outcome was the enoxaparin dose that results in a therapeutic anti-Xa level (0.5–1.0 IU/mL) among three BMI groups. Secondary outcomes were bleeding and thromboembolic events.


Two hundred forty-one patients were included in the study, and 132 achieved a therapeutic dose. For those with a BMI of 40–50 kg/m2, the median therapeutic dose was 0.97 mg/kg every 12 h. In subjects with a BMI of 50–60 kg/m2, the median therapeutic dose was 0.70 mg/kg. Finally, the median therapeutic dose for subjects with a BMI over 60 kg/m2 was 0.71 mg/kg. In all three groups, 53–65% of patients had a supratherapeutic anti-Xa level while less than 10% had a subtherapeutic level. Relatively few patients (4.1%) experienced major bleeding and only one thromboembolic event was reported.


Standard dosing of enoxaparin in morbidly obese patients will most likely lead to supratherapeutic anti-Xa levels and thus further investigation is warranted to better determine appropriate dosing.



The authors wish to acknowledge the contribution of the Texas Tech University Health Sciences Center Clinical Research Institute for their assistance with this research.

Compliance with Ethical Standards


No funding was received in relation to the conduct of this study.

Conflict of interest

Young R. Lee, Peter J. Palmere, Caitlin E. Burton, and Taylor M. Benavides declare that they have no conflict of interest.

Informed Consent

For this type of study, formal consent is not required.

Ethics Approval

Our study was reviewed and approved by the Texas Tech University Health Sciences Center Institutional Review Board.


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Copyright information

© Springer Nature Switzerland AG 2019

Authors and Affiliations

  1. 1.Adult Medicine Division, Department of Pharmacy Practice, Jerry H. Hodge School of PharmacyTexas Tech University Health Sciences CenterAbileneUSA
  2. 2.Jerry H. Hodge School of PharmacyTexas Tech University Health Sciences CenterAbileneUSA

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