Betrixaban

• Venous Thromboembolism Prevention
• DVT Prophylaxis
• Pulmonary Embolism Prevention
• Hospital-Acquired Blood Clots

Betrixaban is an oral direct factor Xa inhibitor anticoagulant approved for the prevention of venous thromboembolism (VTE) in hospitalized acutely ill medical patients at risk for thromboembolic complications. This medication provides an extended duration of thromboprophylaxis compared to traditional approaches.

Mechanism of Action

Betrixaban is a highly selective, reversible direct inhibitor of factor Xa, a serine protease that plays a critical role in the blood coagulation cascade. Factor Xa catalyzes the conversion of prothrombin to thrombin, and thrombin is essential for fibrin clot formation. By inhibiting factor Xa, betrixaban reduces thrombin generation and subsequent clot formation. Unlike heparin-based anticoagulants that require antithrombin III as a cofactor, betrixaban directly and reversibly binds to factor Xa, providing more predictable anticoagulation without routine monitoring.

Available Formulations

Betrixaban is available as oral capsules in 40 mg and 80 mg strengths. The capsules should be taken with food to optimize absorption. The medication should be stored at room temperature.

Medical Uses

Betrixaban is FDA-approved for prophylaxis of venous thromboembolism (VTE) in adult patients hospitalized for an acute medical illness who are at risk for thromboembolic complications due to moderate or severe restricted mobility and other risk factors for VTE. The APEX trial demonstrated that extended-duration betrixaban significantly reduced the composite of asymptomatic or symptomatic proximal deep vein thrombosis, symptomatic pulmonary embolism, or VTE-related death compared to standard-duration enoxaparin.

Dosing Guidelines

The recommended dose is an initial single dose of 160 mg, followed by 80 mg once daily for 35-42 days. The medication should be taken at the same time each day with food. Dose reduction is required for severe renal impairment (CrCl 15-30 mL/min): 80 mg initial dose followed by 40 mg once daily. The same dose reduction applies to patients taking P-gp inhibitors. If a dose is missed and it cannot be taken on the same day, the dose should be skipped.

Important Safety Information

As with all anticoagulants, betrixaban increases the risk of bleeding, including potentially fatal bleeding. It should not be used in patients with active pathological bleeding. Epidural or spinal hematomas may occur in patients receiving neuraxial anesthesia or undergoing spinal puncture while on betrixaban, potentially resulting in long-term or permanent paralysis. The medication should be discontinued at least 72 hours prior to any invasive procedure with bleeding risk. No specific reversal agent is available, though andexanet alfa may have some effect.

Drug Interactions

P-glycoprotein (P-gp) inhibitors increase betrixaban exposure. Patients taking strong P-gp inhibitors (ketoconazole, amiodarone, verapamil) require dose reduction. Concomitant use with other anticoagulants, antiplatelet agents, and NSAIDs increases bleeding risk. Betrixaban is not significantly metabolized by CYP enzymes and is unlikely to have metabolic drug interactions. Avoid concurrent use with other anticoagulants except during transition periods.

Special Populations

There are no adequate data on betrixaban use in pregnant women. Animal studies showed no evidence of fetal harm. It is unknown whether betrixaban is excreted in human breast milk. Safety and efficacy have not been established in pediatric patients. Elderly patients do not require dose adjustment based on age alone. Dose reduction is required for severe renal impairment (CrCl 15-30 mL/min); the medication is not recommended for patients on dialysis. No dose adjustment is needed for mild to moderate hepatic impairment; avoid use in severe hepatic impairment.