BetriXa80 mg

BetriXa is a direct-acting oral factor Xa inhibitor (anticoagulant). Its indications, classified by strength of evidence, are as follows:

Established / FDA-approved use

• Prophylaxis of venous thromboembolism (VTE) in adult patients hospitalized for an acute medical illness who are at risk of thromboembolic complications because of moderate or severe restricted mobility and other risk factors for VTE, given for an extended duration (typically 35 to 42 days) that continues beyond the usual hospital stay.

Not established / off-label

BetriXa is not approved and does not have guideline-supported evidence for stroke prevention in non-valvular atrial fibrillation, treatment of acute deep vein thrombosis (DVT) or pulmonary embolism (PE), use after hip or knee replacement surgery, or use in patients with mechanical/prosthetic heart valves. Use of BetriXa for any of these purposes would be off-label and is not recommended outside specialist clinical judgement.

Each film-coated tablet contains Betrixaban (as betrixaban maleate) in a strength of 40 mg or 80 mg, together with standard pharmaceutically acceptable excipients.

BetriXa is a small-molecule, non-vitamin K antagonist oral anticoagulant (a "direct oral anticoagulant" or DOAC) that selectively and directly inhibits activated factor Xa. It is administered orally as a once-daily tablet and is used for extended-duration prevention of blood clots in hospitalized, acutely ill medical patients at elevated thromboembolic risk. Compared with older anticoagulants such as warfarin, BetriXa has a more predictable pharmacokinetic profile, minimal reliance on hepatic CYP450 metabolism, and does not require routine coagulation monitoring.

Oral Anticoagulant - Direct Factor Xa Inhibitor

Betrixaban is a direct, selective, and reversible inhibitor of factor Xa, a key enzyme in the coagulation cascade that converts prothrombin to thrombin. By inhibiting both free and clot-bound factor Xa, Betrixaban reduces thrombin generation and subsequent fibrin clot formation, without requiring a cofactor such as antithrombin III.

Pharmacokinetics

• Absorption: Peak plasma concentration reached approximately 3-4 hours after oral dosing; absorption is enhanced when taken with food.
• Distribution: Highly protein bound (~60%); moderate volume of distribution.
• Metabolism: Minimally metabolized; not a significant substrate of CYP450 enzymes, reducing risk of metabolic drug interactions. It is a substrate of the P-glycoprotein (P-gp) efflux transporter.
• Elimination: Eliminated mainly unchanged via biliary/fecal excretion, with a smaller portion excreted renally (~11%). Elimination half-life is approximately 19 to 27 hours, supporting once-daily dosing.

BetriXa should be taken by mouth once daily at approximately the same time each day, with food, to enhance absorption. Tablets should be swallowed whole with water and not crushed or chewed unless a physician advises otherwise. Treatment should begin as close to hospital admission as possible and be continued for the full prescribed duration; missed doses should not be doubled up - contact a physician for guidance if a dose is missed.

Clinically significant interactions with BetriXa include:

• P-glycoprotein (P-gp) inhibitors (e.g., amiodarone, verapamil, clarithromycin, ketoconazole): increase BetriXa plasma exposure and bleeding risk; the dose of BetriXa should be reduced (80 mg loading, then 40 mg once daily) when co-administered.
• Antiplatelet agents and NSAIDs (e.g., aspirin, clopidogrel, ibuprofen): increased risk of bleeding when used concomitantly with BetriXa; avoid unless the combination is clinically necessary, with close monitoring.
• Other anticoagulants (e.g., heparin, warfarin, other DOACs): concurrent use increases bleeding risk and is generally avoided except during a supervised transition between agents.

Inform the prescriber of all other medicines, supplements, and herbal products being used before starting BetriXa.

The most common adverse effect of BetriXa is bleeding, which can range from minor to major/life-threatening. Other reported adverse effects include:

• Nausea
• Bruising or minor skin bleeding
• Anemia
• Wound-site bleeding or hematoma (post-surgical patients)

Seek urgent medical attention for signs of serious bleeding such as unusual bruising, blood in urine or stool, coughing/vomiting blood, severe headache, or signs of spinal/epidural hematoma (see Precautions and Warnings).

Pregnancy: Data on the use of BetriXa in pregnant women are limited. BetriXa should be used during pregnancy only if clearly needed and the potential benefit justifies the potential risk to the fetus; consult a physician before use.

Lactation: It is not known whether BetriXa is excreted in human breast milk. Because of the potential for serious adverse reactions (including bleeding) in a nursing infant, a decision should be made whether to discontinue breastfeeding or discontinue BetriXa, taking into account the importance of the drug to the mother; consult a physician.

Boxed Warnings

• Spinal/epidural hematoma: Patients receiving BetriXa who undergo neuraxial anesthesia (spinal/epidural) or spinal puncture are at risk of developing an epidural or spinal hematoma, which can result in long-term or permanent paralysis. Careful timing of catheter placement/removal relative to dosing is required, and patients should be monitored for signs of neurological impairment.
• Premature discontinuation: Discontinuing BetriXa before completing the prescribed course increases the risk of thrombotic events. If BetriXa must be stopped for a reason other than active bleeding, consider covering the patient with an alternative anticoagulant.

Other Precautions

• Use with caution in patients with renal impairment; dose adjustment is required in severe renal impairment (see Dosage and Administration).
• Increased bleeding risk with concomitant antiplatelet agents or NSAIDs (see Interactions).
• Not recommended in patients with prosthetic/mechanical heart valves.
• Not studied and not recommended in severe hepatic impairment (see Contraindications).

Overdose of BetriXa may increase the risk of bleeding. There is no specific antidote widely established for reversing the anticoagulant effect of BetriXa. In case of suspected overdose, seek immediate medical attention or contact emergency services/a poison control center. Management is generally supportive and may include discontinuation of the drug, local hemostatic measures, and, in cases of serious bleeding, transfusion or other supportive care as directed by a physician; do not attempt home treatment for suspected overdose.

Store at room temperature (below 30°C), away from light and moisture. Keep out of reach of children.

Renal impairment: Dose reduction is required in patients with severe renal impairment (see Dosage and Administration); BetriXa has not been studied in patients on dialysis.

Hepatic impairment: No dose adjustment needed in mild-to-moderate impairment; BetriXa is contraindicated in severe hepatic impairment.

Elderly: No specific dose adjustment based on age alone is required, but elderly patients may have increased bleeding risk and should be monitored closely.

Pregnancy and lactation: See Pregnancy and Lactation section.

Pediatric patients: See Pediatric Uses section.

The recommended duration of BetriXa therapy for VTE prophylaxis in acutely ill hospitalized medical patients is 35 to 42 days, beginning at hospital admission and extending beyond the typical hospital stay. Treatment duration should not be shortened or extended without medical advice, as premature discontinuation increases thrombotic risk (see Precautions and Warnings).

Anticoagulants; Direct Oral Anticoagulants (DOACs); Factor Xa Inhibitors

Betrixaban works by directly and selectively binding to the active site of factor Xa, blocking both free factor Xa and factor Xa within the prothrombinase complex. This inhibition prevents the conversion of prothrombin to thrombin, thereby reducing thrombin-mediated fibrin clot formation and platelet activation. Unlike vitamin K antagonists, Betrixaban does not require a cofactor (antithrombin) and provides a rapid, dose-dependent anticoagulant effect.

The safety and efficacy of BetriXa in pediatric patients have not been established. BetriXa is not recommended for use in children or adolescents outside of a clinical trial setting.