Apixaban for DVT Prophylaxis
For DVT prophylaxis following hip or knee replacement surgery in patients with normal renal function, use apixaban 2.5 mg orally twice daily, starting 12-24 hours after surgery, for 12 days after knee replacement or 35 days after hip replacement. 1
Post-Surgical Orthopedic Prophylaxis
The FDA-approved regimen for DVT prophylaxis after orthopedic surgery is straightforward and well-established:
This regimen demonstrated superiority over enoxaparin in the ADVANCE-2 and ADVANCE-3 trials, with significantly lower VTE rates (1.51% vs 24.4% for knee replacement; 1.4% vs 3.9% for hip replacement) and numerically lower bleeding rates 2. A meta-analysis confirmed that oral factor Xa inhibitors including apixaban are superior to enoxaparin in preventing DVT after total hip and knee arthroplasty 3.
Medical Patient Prophylaxis
For acutely ill medical patients, apixaban is NOT recommended for extended thromboprophylaxis based on current evidence.
The ADOPT trial evaluated apixaban 2.5 mg twice daily for 30 days in acutely ill medical patients but showed:
- No superiority over shorter-course enoxaparin (2.71% vs 3.06% VTE rate, RR 0.87) 2
- Significantly increased major bleeding (0.47% vs 0.19%, RR 2.58, p<0.04) 2
Cancer Patient Prophylaxis
For ambulatory cancer patients at high risk (Khorana score ≥2) starting chemotherapy:
- Dose: 2.5 mg orally twice daily 2
- Duration: 6 months 2
- Efficacy: The AVERT trial showed significant VTE reduction (4.2% vs 10.2%, HR 0.41, p<0.001) with NNT of 17 2
Important caveat: Major bleeding was increased (3.5% vs 1.8%, HR 2.00, p=0.046), though on-treatment bleeding rates were not significantly different 2. This requires careful patient selection and monitoring.
Critical Contraindications and Precautions
Avoid apixaban in the following situations:
- Severe renal impairment (CrCl <15 mL/min) 1
- Use caution with CrCl <25 mL/min 1
- Significant hepatic impairment (transaminases >2x upper limit or bilirubin >1.5x upper limit) 1
- Concomitant use with combined P-gp and strong CYP3A4 inhibitors (ketoconazole, ritonavir) in patients already on 2.5 mg twice daily 1
Perioperative Management
When interrupting apixaban for procedures:
- Discontinue 48 hours prior to elective surgery with moderate-to-high bleeding risk 1
- Discontinue 24 hours prior to procedures with low bleeding risk 1
- No bridging anticoagulation is generally required during this interruption 1
- Restart as soon as adequate hemostasis is established 1
Key Distinction: Prophylaxis vs Treatment
Do not confuse prophylaxis dosing with treatment dosing. For DVT prophylaxis, the dose is always 2.5 mg twice daily 1. For acute DVT treatment, the regimen is entirely different: 10 mg twice daily for 7 days, then 5 mg twice daily 1. This distinction is critical to avoid underdosing in treatment scenarios or overdosing in prophylaxis scenarios.