From the Guidelines
The recommended dose of unfractionated heparin for Deep Vein Thrombosis (DVT) prophylaxis is 5,000 units subcutaneously every 8 hours. This dosing regimen is supported by the most recent and highest quality study 1, which provides guidelines for venous thromboembolism prophylaxis and treatment in patients with cancer.
Key Considerations
- The dose of 5,000 units every 8 hours is preferred over 5,000 units every 12 hours, as it appears to be more effective 1.
- For patients with renal impairment, dose adjustments may be necessary, particularly for low molecular weight heparins which are primarily cleared by the kidneys 1.
- Obese patients may require higher doses based on weight 1.
- Prophylaxis should typically begin upon hospital admission or before surgery and continue until the patient is fully mobile or discharged 1.
Mechanism of Action and Monitoring
- The mechanism of action involves heparin binding to antithrombin III, enhancing its ability to inactivate thrombin and factor Xa, thereby preventing clot formation.
- Patients should be monitored for signs of bleeding, and periodic platelet counts are recommended to detect heparin-induced thrombocytopenia, especially with unfractionated heparin 1.
Alternative Prophylaxis Methods
- Mechanical prophylaxis with compression stockings or intermittent pneumatic compression devices should be considered for patients with contraindications to pharmacological prophylaxis 1.
From the Research
Recommended Dose of Heparin for DVT Prophylaxis
The recommended dose of unfractionated heparin for Deep Vein Thrombosis (DVT) prophylaxis varies depending on the patient population and clinical setting.
- For medical patients, including those with heart disease, a dose of 5000 units of unfractionated heparin subcutaneously every 8 hours is recommended 2.
- For trauma patients, a dose of 5000 U of heparin three times a day has been shown to be effective for DVT prophylaxis 3.
- For low body weight critically ill patients, a reduced-dose regimen of heparin 5000 units every 12 h subcutaneously may be considered to minimize the risk of bleeding 4.
- For patients undergoing lower extremity amputation, a dose of 5000 IU of unfractionated heparin three times a day has been used for DVT prophylaxis 5.
- In another study, the starting dose of unfractionated heparin was 15,000 IU/day, which was increased to a plateau value of 28,800 +/- 7,150 IU/day to maintain the activated partial thromboplastin time (aPTT) in the prescribed range 6.
Key Considerations
When selecting a dose of heparin for DVT prophylaxis, it is essential to consider the individual patient's risk factors, such as body weight, renal function, and bleeding risk.
- The dose of heparin may need to be adjusted based on the patient's aPTT levels to ensure effective prophylaxis while minimizing the risk of bleeding.
- The choice of heparin regimen should be based on the specific clinical setting and patient population, as well as the availability of resources and expertise.