Apixaban Dosing for Unprovoked Pulmonary Embolism
For a patient with unprovoked pulmonary embolism being discharged home, the recommended dose of apixaban is 10 mg twice daily for the first 7 days, followed by 5 mg twice daily.
Initial Treatment Phase
- Apixaban should be initiated at 10 mg twice daily for the first 7 days of therapy for patients with pulmonary embolism 1, 2, 3
- No initial parenteral anticoagulation is required before starting apixaban, unlike some other direct oral anticoagulants that require a 5-day lead-in period with heparin 2, 3
- Treatment can begin immediately upon diagnosis, provided there are no contraindications 2
Maintenance Phase
- After the initial 7-day period, the dose should be reduced to 5 mg twice daily 1, 2, 3
- This maintenance dose should be continued for at least 3 months for unprovoked PE 2
- For patients with unprovoked PE, extended anticoagulation beyond 3 months is often necessary due to ongoing risk factors 2
Special Dosing Considerations
- Dose reduction to 2.5 mg twice daily is not indicated for the initial treatment of PE but may be considered after at least 6 months of treatment at full dose for secondary prevention 1, 2, 4
- Dose adjustment to 2.5 mg twice daily should be considered only if the patient has at least two of the following characteristics: age ≥80 years, body weight ≤60 kg, or serum creatinine ≥1.5 mg/dL 1, 3
- For patients with severe renal impairment (CrCl <30 mL/min), apixaban should be used with caution 2, 5
Efficacy and Safety Profile
- Apixaban has been shown to be non-inferior to conventional therapy (LMWH/warfarin) for the treatment of VTE with a recurrence rate of 2.3% vs 2.7% 1
- The risk of major bleeding is significantly lower with apixaban (0.6%) compared to conventional therapy (1.8%) 1, 2
- The composite of major bleeding and clinically relevant non-major bleeding is also significantly lower with apixaban (4.3%) compared to conventional therapy (9.7%) 2
Common Pitfalls to Avoid
- Do not administer loading doses of parenteral anticoagulants when initiating apixaban, as this increases bleeding risk 2
- Do not continue the initial higher dose (10 mg twice daily) beyond the first 7 days 2, 3
- Do not reduce the dose to 2.5 mg twice daily during the initial treatment phase, as this would result in underdosing and potentially increase the risk of recurrent VTE 1
- Avoid inappropriate dose reduction based on perceived bleeding risk alone, as this may lead to treatment failure 1
- Be aware that apixaban interacts with combined P-glycoprotein and strong CYP3A4 inhibitors, which may require dose adjustment 5, 3
Monitoring and Follow-up
- Unlike warfarin, apixaban does not require routine coagulation monitoring 2
- Regular assessment for signs of bleeding or recurrent thromboembolism is recommended 1
- After at least 6 months of treatment, the decision to continue or adjust the dose should be based on the patient's risk of recurrence versus bleeding 1, 4