Apixaban Dosing for Pulmonary Embolism: 10mg BD for First 7 Days
The 10mg twice daily dosing of apixaban for the first 7 days of pulmonary embolism treatment is the standard loading dose regimen that ensures rapid therapeutic anticoagulation before transitioning to the maintenance dose, regardless of when the PE was diagnosed. 1
Evidence-Based Dosing Regimen
The FDA-approved dosing regimen for apixaban in pulmonary embolism treatment follows a specific schedule:
- Initial phase: 10mg taken orally twice daily for the first 7 days
- Maintenance phase: 5mg taken orally twice daily after the initial 7 days
- Extended prevention: After at least 6 months of treatment, may reduce to 2.5mg twice daily 2, 1
This dosing schedule is based on the AMPLIFY trial, which demonstrated apixaban's non-inferiority to conventional therapy for preventing recurrent VTE while significantly reducing major bleeding risk 3.
Why the Loading Dose Is Still Needed 20 Days After Diagnosis
Even though your PE was diagnosed 20 days ago, the loading dose is still required when initiating apixaban therapy because:
- Pharmacokinetic considerations: The loading dose ensures rapid achievement of therapeutic anticoagulation levels in the blood
- Evidence-based protocol: The clinical trials that established apixaban's efficacy used this specific dosing regimen
- FDA and guideline requirements: The approved dosing protocol must be followed regardless of when the PE was diagnosed 1
Clinical Implications of Skipping the Loading Dose
Skipping the loading dose and starting directly with the 5mg twice daily maintenance dose could:
- Result in subtherapeutic anticoagulation levels
- Increase the risk of thrombus extension or recurrent PE
- Deviate from evidence-based practice that established safety and efficacy
Special Considerations
- Renal function: No dose adjustment is needed for mild to moderate renal impairment, but apixaban should be avoided in severe renal impairment (CrCl <30 ml/min) 3
- Drug interactions: Dose should be reduced by 50% if taking combined P-gp and strong CYP3A4 inhibitors 1
- Bleeding risk: Despite the higher initial dose, apixaban has demonstrated lower bleeding risk compared to conventional therapy 3
Transition from Other Anticoagulants
If you were previously on another anticoagulant for your PE:
- From warfarin: Discontinue warfarin and start apixaban when INR is below 2.0
- From other anticoagulants: Discontinue the previous anticoagulant and begin apixaban at the time the next dose would have been taken 1
The 10mg twice daily loading dose for 7 days is still required when transitioning from other anticoagulants to ensure proper therapeutic levels are achieved.