Is it okay to use Eliquis (apixaban) 2.5mg twice daily for Deep Vein Thrombosis (DVT) prophylaxis in a patient with Traumatic Brain Injury (TBI)?

Use of Apixaban 2.5mg BID for DVT Prophylaxis in TBI Patients

Apixaban 2.5mg twice daily is appropriate for DVT prophylaxis in TBI patients, but should only be initiated after a head CT confirms that intracranial hemorrhage is stable and persistent bleeding has stopped, typically 24-72 hours after injury. 1

Risk of VTE in TBI Patients

TBI patients are at significantly elevated risk for venous thromboembolism:

• TBI alone increases DVT risk by 2.59 times compared to non-TBI trauma patients 2
• VTE incidence in TBI patients ranges from 5-30%, with rates of 11-30% reported in patients without prophylaxis 3
• Even with best-practice prophylaxis, VTE rates of approximately 11% have been observed in severe TBI patients 4

Timing of Anticoagulation Initiation

The European guideline on management of major bleeding and coagulopathy following trauma (2023) provides clear guidance:

• Pharmacological VTE prophylaxis should be initiated as early as possible
• Prophylaxis should only begin after a head CT confirms ICH stability
• There should be no evidence of persistent bleeding 1

Retrospective studies show that initiating prophylaxis within 24-72 hours of injury results in fewer VTE events without increased bleeding risk compared to later initiation 1.

Appropriate Anticoagulant Selection

For DVT prophylaxis in TBI patients:

1. LMWH is traditionally the first-line agent recommended by guidelines 1, 5
2. Apixaban 2.5mg twice daily is an appropriate alternative:
   • This is the FDA-approved prophylactic dose for VTE prevention 6
   • Studies show reduced-dose apixaban (2.5mg twice daily) is effective for VTE prophylaxis 1

Monitoring and Precautions

When using apixaban 2.5mg BID in TBI patients:

• Regular neurological assessments to monitor for signs of ICH progression
• Consider dose adjustment in patients with:
  • Severe renal impairment (CrCl <15 mL/min) - avoid use 1
  • Hepatic impairment - avoid in patients with elevated liver enzymes >2x normal or bilirubin >1.5x normal 1
  • Concomitant use of strong CYP3A4 inhibitors (e.g., ketoconazole, ritonavir) - contraindicated 1

Duration of Prophylaxis

• Continue prophylaxis until the patient is fully mobile or discharged from the hospital 5
• For high-risk patients, consider extended prophylaxis for up to 4 weeks 5

Common Pitfalls and Caveats

1. Premature initiation: Starting anticoagulation before confirming ICH stability increases risk of hemorrhage progression
2. Delayed initiation: Waiting too long (>72 hours) may increase VTE risk unnecessarily
3. Inadequate monitoring: Failure to reassess neurological status and bleeding risk regularly
4. Drug interactions: Not accounting for medications that affect apixaban metabolism through CYP3A4 pathways
5. False security: Relying solely on pharmacological prophylaxis without considering mechanical methods in highest-risk patients

In summary, apixaban 2.5mg BID is an appropriate choice for DVT prophylaxis in TBI patients once ICH stability is confirmed, typically 24-72 hours after injury, with no evidence of persistent bleeding.