Apixaban Dosing for Chronic DVT
For chronic DVT treatment, apixaban should be dosed at 10 mg orally twice daily for the first 7 days, followed by 5 mg orally twice daily for continued treatment, and if extended anticoagulation beyond 6 months is needed, reduce to 2.5 mg twice daily for secondary prevention. 1
Initial Treatment Phase (Days 1-7)
- Start with 10 mg orally twice daily for 7 days as the loading dose regimen to achieve rapid anticoagulation 2, 3, 1
- No initial parenteral anticoagulation (such as heparin or enoxaparin) is required before starting apixaban, which simplifies treatment compared to warfarin 2, 3
- This loading dose was validated in the AMPLIFY trial, demonstrating non-inferiority to conventional enoxaparin/warfarin therapy with significantly lower bleeding rates (0.6% vs 1.8% major bleeding) 4, 5
Maintenance Phase (After Day 7)
- Transition to 5 mg orally twice daily after the initial 7 days 2, 3, 1
- Continue this dose for at least 3 months for provoked DVT 2, 3
- For unprovoked DVT or patients with ongoing risk factors, consider longer treatment duration beyond 3 months 2, 3
- The 5 mg twice daily maintenance dose provides equivalent efficacy to conventional therapy while maintaining the reduced bleeding risk 5
Extended Treatment Phase (Beyond 6 Months)
- For patients requiring extended anticoagulation beyond 6 months, reduce to 2.5 mg orally twice daily for secondary prevention 2, 3, 1
- This lower dose minimizes bleeding risk while maintaining efficacy for preventing recurrent DVT 2
- Extended treatment with the 2.5 mg dose has been shown to reduce recurrent VTE risk without increasing major bleeding rates 6
Key Advantages
- Fixed-dose regimen eliminates the need for routine laboratory monitoring (no INR checks required) 2, 7
- Significantly lower major bleeding risk compared to warfarin (relative risk 0.31) 5
- Rapid onset of action with predictable pharmacokinetics 7
Important Caveats and Dose Adjustments
- Avoid in severe renal impairment (CrCl <15 mL/min) and use caution with CrCl <25 mL/min 4
- Avoid in significant hepatic impairment (transaminases >2x upper limit of normal or total bilirubin >1.5x upper limit of normal) 4
- Reduce dose by 50% when coadministered with combined P-glycoprotein and strong CYP3A4 inhibitors (ketoconazole, itraconazole, ritonavir) if taking 5 mg or 10 mg twice daily 1
- Avoid coadministration with these inhibitors if already taking 2.5 mg twice daily 1
Special Population: Cancer-Associated DVT
- While apixaban has shown promise in cancer-associated VTE with non-inferiority to dalteparin, the 2013 NCCN guidelines noted insufficient data in cancer patients at that time (only 2.7% of AMPLIFY trial participants had cancer) 4
- More recent evidence supports apixaban as a viable option for cancer-associated DVT 2