Why is Clexane (Enoxaparin) more effective than Fondaparinux in postpartum?

From the Guidelines

Clexane (Enoxaparin) is more effective than Fondaparinux in postpartum due to its better bioavailability, longer half-life, more predictable anticoagulation effect, less bleeding risks, and less risk of heparin-induced thrombocytopenia and osteopenia 1.

Key Points

• The American Society of Hematology guidelines recommend the use of Low-Molecular-Weight Heparin (LMWH) over Fondaparinux in pregnancy due to limited data on Fondaparinux's safety in this setting 1.
• Enoxaparin, a type of LMWH, has been shown to have a greater anticoagulant effect than Unfractionated Heparin (UH) in postpartum women, with 73% of patients receiving 40 mg enoxaparin showing hypocoagulable results compared to 47% receiving 7500 IU UH 1.
• The recommended dose of enoxaparin for prophylaxis is typically 40 mg subcutaneously once a day, with obese women potentially requiring higher doses 1.
• The use of Fondaparinux is generally reserved for women with Heparin-Induced Thrombocytopenia (HIT) or other specific conditions, due to concerns about its safety and efficacy in pregnancy 1.
• The Society for Maternal-Fetal Medicine recommends the use of LMWH as the preferred thromboprophylactic agent in pregnancy and the postpartum period, with enoxaparin being a commonly used option 1.

From the Research

Comparison of Clexane (Enoxaparin) and Fondaparinux in Postpartum

• The effectiveness of Clexane (Enoxaparin) and Fondaparinux in postpartum thromboprophylaxis has been evaluated in several studies 2, 3, 4, 5, 6.
• A study comparing the safety and effectiveness of Fondaparinux as a postpartum thromboprophylaxis found that Fondaparinux is a safe alternative thromboprophylaxis for postpartum women, with no cases of venous thromboembolism (VTE) reported 2.
• However, another study found that Enoxaparin is more effective than Fondaparinux in achieving prophylactic anti-Xa levels, with a higher proportion of women achieving prophylactic levels with Enoxaparin 4.
• Weight-based Enoxaparin dosing has been shown to be more effective than fixed-dose Enoxaparin in achieving prophylactic anti-Xa levels after cesarean delivery, with a higher proportion of women achieving prophylactic levels with weight-based dosing 5.
• A systematic review of pentasaccharides, including Fondaparinux, found that Fondaparinux is 50% more effective in reducing VTE than Enoxaparin in major orthopedic surgery, but with an overall 1% increased rate of major bleeding 6.

Pharmacokinetics and Dosage

• The pharmacokinetics of Enoxaparin during pregnancy and the postpartum period have been evaluated, with findings suggesting that clearance of the drug is higher in pregnant women throughout pregnancy compared to nonpregnant women 3.
• A study comparing two weight-based Enoxaparin dosing protocols found that administration of Enoxaparin at 1 mg/kg once daily was superior to weight categories in reaching anti-Xa prophylactic levels without leading to serious adverse effects 4.
• Weight-based Enoxaparin dosing has been shown to be more effective than fixed-dose Enoxaparin in achieving prophylactic anti-Xa levels after cesarean delivery, with a higher proportion of women achieving prophylactic levels with weight-based dosing 5.

Safety and Efficacy

• Fondaparinux has been found to be a safe alternative thromboprophylaxis for postpartum women, with no cases of VTE reported and no major bleeding events 2.
• Enoxaparin has been shown to be effective in preventing VTE in postpartum women, with a higher proportion of women achieving prophylactic anti-Xa levels with weight-based dosing 4, 5.
• The incidence of fatal bleeding, critical organ bleeding, or bleeding leading to reoperation did not differ significantly between Fondaparinux and Enoxaparin treatment groups 6.