What is the recommended apixaban dosing regimen, dose‑adjustment criteria, contraindications, and alternative therapy for an adult with acute deep‑vein thrombosis?

Apixaban Treatment for Acute Deep Vein Thrombosis

For acute DVT in adults without cancer, initiate apixaban 10 mg orally twice daily for 7 days, then reduce to 5 mg twice daily for at least 3 months, with no parenteral anticoagulant bridge required. 1, 2

Dosing Regimen

Loading Phase (Days 1-7)

• 10 mg orally twice daily for the first 7 days 3, 4, 1, 2
• Start immediately upon diagnosis confirmation—no heparin bridge needed 1
• This differs from edoxaban and dabigatran, which require 5-10 days of parenteral anticoagulation first 3

Maintenance Phase (Day 8 onwards)

• 5 mg orally twice daily for minimum 3 months 3, 4, 1, 2
• Reassess at 3 months for extended therapy needs 3

Extended Prophylaxis (After ≥6 months)

• 2.5 mg orally twice daily to reduce recurrence risk in patients requiring long-term therapy 3, 2
• This reduced dose is only for extended prophylaxis, never for acute treatment 1

Dose Adjustment Criteria

Renal Function

• Absolute contraindication: CrCl <15 mL/min 3, 4, 1, 2
• Calculate creatinine clearance using Cockcroft-Gault equation 1
• Approximately 27% renal elimination, making it safer than rivaroxaban (66% renal) or edoxaban (50% renal) in moderate renal impairment 3, 4
• No dose reduction needed for CrCl ≥15 mL/min when treating acute DVT 2

Hepatic Function

• Contraindicated if transaminases >2× upper limit normal OR total bilirubin >1.5× upper limit normal 4, 1
• Avoid in severe hepatic impairment 3

Age and Weight

• No dose adjustment for age or weight during acute DVT treatment 2
• The 2.5 mg twice-daily dose used in atrial fibrillation (age ≥80, weight ≤60 kg, creatinine ≥1.5 mg/dL) does NOT apply to VTE treatment 2

Absolute Contraindications

• Active pathological bleeding 2
• CrCl <15 mL/min 3, 4, 1
• Severe hepatic impairment (transaminases >2× ULN or bilirubin >1.5× ULN) 4, 1
• Hypersensitivity to apixaban 2

Monitoring Requirements

Baseline Laboratory Assessment

• Complete blood count with platelet count 1
• Comprehensive metabolic panel including serum creatinine 1
• Hepatic function panel (AST, ALT, total bilirubin) 1
• Baseline PT/INR and aPTT for documentation only—not for ongoing monitoring 4, 1

During Treatment

• Hemoglobin/hematocrit every 2-3 days for first 14 days if inpatient, then every 2 weeks 1
• Reassess renal function periodically, especially in elderly patients 1
• Do NOT monitor INR, anti-factor Xa levels, or D-dimer routinely 4, 1

Clinical Monitoring

• Assess for bleeding signs: bruising, hematuria, melena, hemoptysis, neurological changes 1
• Monitor for recurrent VTE: new leg swelling, chest pain, dyspnea 4, 1

Evidence Supporting This Regimen

The AMPLIFY trial (5,395 patients) demonstrated apixaban was noninferior to enoxaparin/warfarin for preventing recurrent VTE (2.3% vs 2.7%; RR 0.84,95% CI 0.60-1.18) with significantly lower major bleeding (0.6% vs 1.8%; RR 0.31,95% CI 0.17-0.55; P<0.001) 3, 5. This high-quality evidence from 2013 established the current dosing standard 1.

Alternative Therapy

Cancer-Associated DVT

• Low molecular weight heparin (LMWH) remains preferred over apixaban 3, 6
• Apixaban and edoxaban are NCCN Category 1 alternatives based on ADAM VTE and Caravaggio trials 3
• The 2024 NCCN guidelines note apixaban showed equivalent efficacy to dalteparin with lower bleeding rates in cancer patients 3

If Apixaban Contraindicated

• Rivaroxaban: 15 mg twice daily × 3 weeks, then 20 mg daily 3
• Edoxaban: requires 5-10 days parenteral anticoagulation first, then 60 mg daily (30 mg if CrCl 30-50 mL/min or weight <60 kg) 3
• LMWH followed by warfarin (target INR 2-3) 3, 5

Critical Pitfalls to Avoid

• Never use 2.5 mg twice daily for acute DVT treatment—this dose is only for extended prophylaxis after completing ≥6 months of full-dose therapy 1, 2
• Do not bridge with heparin before starting apixaban—direct initiation is recommended 1
• Do not monitor INR—apixaban affects INR unpredictably and dose adjustments based on INR are inappropriate 4
• Stop apixaban 48 hours before moderate/high-bleeding-risk surgery, 24 hours before low-risk procedures 2
• Wait 24-72 hours after major bleeding or surgery before restarting to ensure adequate hemostasis 1

Switching Between Anticoagulants

From Warfarin to Apixaban

• Discontinue warfarin and start apixaban when INR <2.0 2

From Apixaban to Warfarin

• Discontinue apixaban and begin parenteral anticoagulant plus warfarin at time of next apixaban dose 2
• Stop parenteral agent when INR therapeutic 2

From/To Other Anticoagulants

• Simply discontinue one and start the other at the time of the next scheduled dose 2