Low molecular weight heparin

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For more information, see: heparin.

In hematology, low molecular weight heparin (LMWH) is an anticoagulant that consists of "heparin fractions with a molecular weight usually between 4000 and 6000 kD. These low-molecular-weight fractions are effective antithrombotic agents. Their administration reduces the risk of hemorrhage, they have a longer half-life, and their platelet interactions are reduced in comparison to unfractionated heparin. They also provide an effective prophylaxis against postoperative major pulmonary embolism."[1]

Selected low molecular weight heparins
  Prophylaxis dose Full dose Comments
Enoxiparin
(Lovenox)
Either:
30 mg twice daily
40 mg once daily
Either:
1 mg/kg/dose every 12 hours
1.5 mg/kg once daily
more information is at Enoxaparin
 
Dalteparin
(Framin)
After loading, 2500 to 5000 int. units daily 150 int. units/kg up to 18,000 int. units) once daily
dosing is complicated and more information is at DailyMed
If creatinine clearance is less then 30 mL/minute, monitor anti-Xa levels

Oncology

Venous thromboembolism (VTE), usually as pulmonary embolism (PE) or deep vein thrombosis, is the second leading cause of death in patients with cancer. While less than 5% of cancer patients routinely receive VTE prophylaxis, for which LMWH is preferred,[2] the American Society of Clinical Oncology (ASCO),[3] the American College of Chest Physicians (ACCP),[4] and the National Comprehensive Cancer Network (NCCN)[5] have all recently issued clinical practice guidelines for the prevention and treatment of cancer-associated thrombosis.

The use of prophylactic LMWH in cancer patients with central venous catheters, however, was not found to be an adequate risk factor for their use. [6]

Intensive care medicine and interventional radiology

The presumed lack of bedside measurements of anticoagulation has limited the use of these agents for percutaneous coronary intervention (PCI). Investigators found, in a small trial, that the activated clotting time ACT: is equally sensitive to IV enoxaparin and dalteparin. "These data support an ACT-guided strategy for intravenously administered LMWH during PCI. Additional studies with larger patient populations may be indicated to determine the ideal target ACT for LMWH in PCI."[7]

Post-surgical VTE prophylaxis

References

  1. Anonymous (2024), Low molecular weight heparin (English). Medical Subject Headings. U.S. National Library of Medicine.
  2. Khorana AA (2009), "Cancer and Thrombosis: Implications of Published Guidelines for Clinical Practice", Annals of Oncology 20 (10): 1619-1630
  3. Lyman GH, Khorana AA, Falanga A, et al. American Society of Clinical Oncology guideline: recommendations for venous thromboembolism prophylaxis and treatment in patients with cancer. J Clin Oncol 2007; 25: 5490-5505.
  4. Geerts WH, Bergqvist D, Pineo GF, et al. Prevention of venous thromboembolism: American College of Chest Physicians Evidence-Based Clinical Practice Guidelines. (8th edition). Chest 2008; 133: (6 Suppl): 381S-453S.
  5. NCCN Clinical Practice Guidelines in Oncology. Venous Thromboembolic Disease. http://www.nccn.org/professionals/physician_gls/PDF/vte.pdf. (1 November 2008, date last accessed)
  6. P. Debourdeau, et al.', on behalf of the working group of the SOR (2009), "2008 SOR Guidelines for the Prevention and Treatment of Thrombosis Associated with Central Venous Catheters in Patients with Cancer: Report from the Working Group: 2008 SOR Guidelines", Annals of Oncology 20 (9): 1459-1471
  7. Erdal Cavusoglu, Manish Lakhani, Jonathan D. Marmur (2005), "The Activated Clotting Time (ACT) Can Be Used to Monitor Enoxaparin and Dalteparin After Intravenous Administration", The Journal of Invasive Cardiology 17 (8): 416-421