From the Guidelines
Low molecular weight (LMW) heparins are indicated for prevention and treatment of venous thromboembolism (VTE), including deep vein thrombosis (DVT) and pulmonary embolism (PE), as well as for treatment of acute coronary syndromes, such as unstable angina and non-ST elevation myocardial infarction, as supported by the most recent evidence from 1.
Indications for LMW Heparin
- Prevention and treatment of VTE, including DVT and PE
- Thromboprophylaxis in hospitalized patients with reduced mobility, following orthopedic surgery, general surgery, and in medical patients at high risk for thrombosis
- Treatment of acute coronary syndromes, such as unstable angina and non-ST elevation myocardial infarction
- Bridging therapy for patients on warfarin requiring temporary interruption of anticoagulation
Advantages of LMW Heparin
- Predictable pharmacokinetics
- Less monitoring requirements
- Lower risk of heparin-induced thrombocytopenia
- Convenient once or twice daily subcutaneous administration
Dosing of LMW Heparin
- Typical prophylactic dosing for enoxaparin is 40mg subcutaneously once daily or 30mg twice daily
- Treatment doses are weight-based (1mg/kg twice daily or 1.5mg/kg once daily)
Mechanism of Action
- LMW heparins work by binding to antithrombin, enhancing its inhibitory effect on coagulation factors Xa and IIa, with greater activity against factor Xa than unfractionated heparin, as described in 1.
Special Considerations
- LMW heparins are preferred during pregnancy for VTE treatment due to their safety profile, as they don't cross the placenta, as noted in 1.
- Dosage reduction may be necessary in patients with renal insufficiency, as suggested by 1.
From the Research
Indications for Low Molecular Weight Heparin
The indications for giving Low Molecular Weight (LMW) Heparin include:
- Treatment of venous thromboembolism, including deep vein thrombosis and pulmonary embolism 2, 3, 4
- Prophylaxis against deep vein thrombosis in critically ill patients undergoing major surgery 5
- Treatment of patients with symptomatic venous thromboembolism, including those with associated pulmonary embolism or a history of venous thromboembolism 3
- Initial management of venous thromboembolism, regardless of whether the patient has pulmonary embolism or a history of venous thromboembolism 3
Benefits of Low Molecular Weight Heparin
The benefits of LMW Heparin include:
- Increased bio-availability and prolonged half-life, permitting once daily subcutaneous injections 2
- Predictable antithrombotic response based on body weight, allowing treatment without laboratory monitoring 2
- Less bleeding compared to unfractionated heparin 2, 6
- Decreased incidence of heparin-induced thrombocytopenia and osteoporosis 2
- Effective and safe for out-of-hospital treatment of venous thrombosis 2
Comparison with Unfractionated Heparin
LMW Heparin has been compared to unfractionated heparin in several studies, with results showing: