From the Guidelines
For preoperative DVT prophylaxis in a patient with pork allergy, I recommend using synthetic alternatives such as fondaparinux (Arixtra) 2.5 mg subcutaneously once daily, starting 6-8 hours after surgery, as the most recent and highest quality study suggests its efficacy and safety in this setting 1. The concern with pork allergy is relevant because traditional unfractionated heparin is derived from porcine intestinal mucosa, and some low molecular weight heparins like enoxaparin may also contain porcine components. Fondaparinux is a synthetic pentasaccharide that selectively inhibits factor Xa without using any animal products. Some key points to consider when choosing a DVT prophylaxis option for a patient with a pork allergy include:
- The patient's specific allergy details, as some patients may confuse pork dietary restrictions with true allergies to porcine medical products
- The use of direct oral anticoagulants (DOACs) like rivaroxaban (Xarelto) 10 mg daily or apixaban (Eliquis) 2.5 mg twice daily as alternative options for appropriate surgical patients
- The importance of verifying the patient's allergy status and medical history to ensure the chosen prophylaxis option is safe and effective
- The potential benefits of using mechanical prophylaxis, such as intermittent pneumatic compression devices or graduated compression stockings, in conjunction with pharmacological methods when possible, especially in high-risk patients 1. It's also important to note that the American College of Chest Physicians suggests low-dose aspirin, fondaparinux, or mechanical prophylaxis as alternatives when LMWH and unfractionated heparin are contraindicated or unavailable 1.
From the FDA Drug Label
Fondaparinux sodium injection is indicated for the prophylaxis of deep vein thrombosis (DVT), which may lead to pulmonary embolism (PE): in patients undergoing hip fracture surgery, including extended prophylaxis; in patients undergoing hip replacement surgery; in patients undergoing knee replacement surgery; in patients undergoing abdominal surgery who are at risk for thromboembolic complications.
The patient can be given fondaparinux for preop DVT prophylaxis if they are allergic to pork, as fondaparinux is a synthetic anticoagulant and does not contain any pork products 2.
- The recommended dose of fondaparinux sodium injection for DVT prophylaxis is 2.5 mg administered by subcutaneous injection once daily after hemostasis has been established.
- Administer the initial dose no earlier than 6 to 8 hours after surgery.
- The usual duration of therapy is 5 to 9 days.
From the Research
Preoperative DVT Prophylaxis Options for Patients Allergic to Pork
- For patients allergic to pork, alternative DVT prophylaxis options can be considered, such as mechanical prophylaxis or pharmacological agents that do not contain pork products 3.
- Fondaparinux, a synthetic, non-heparin anticoagulant, has been shown to be effective in preventing VTE in high-risk patients, including those undergoing orthopedic surgery 4, 5.
- Low-molecular-weight heparins (LMWHs), such as enoxaparin, are also effective in preventing DVT, but may not be suitable for patients with a pork allergy 6, 7.
- Other pharmacological options, such as factor Xa inhibitors (e.g., rivaroxaban, edoxaban) and thrombin inhibitors, may also be considered, but their use should be guided by individual patient risk factors and bleeding risk assessment 7.
- Mechanical prophylaxis, such as intermittent pneumatic compression devices or venous foot pumps, can be used alone or in combination with pharmacological agents, especially in patients at high risk of bleeding 3, 6.