Apixaban Dosing for Superficial Vein Thrombosis with Extension into the Common Femoral Vein
For SVT extending into the CFV, treat with apixaban 10 mg orally twice daily for 7 days, followed by 5 mg orally twice daily for at least 3 months, as this represents deep venous system involvement requiring full therapeutic anticoagulation per VTE treatment protocols. 1, 2, 3
Rationale for Full VTE Treatment Dosing
Once superficial thrombophlebitis extends into the common femoral vein (a deep vein), this becomes a deep vein thrombosis requiring full therapeutic anticoagulation, not prophylactic dosing. 1, 2
Initial loading phase: 10 mg orally twice daily for the first 7 days achieves rapid therapeutic anticoagulation without requiring parenteral bridging. 1, 2, 3
Maintenance phase: After 7 days, continue 5 mg orally twice daily for a minimum of 3 months for provoked DVT, or longer if unprovoked or ongoing risk factors exist. 1, 2
Dose Reduction Criteria (For Atrial Fibrillation Only - NOT Applicable Here)
Critical pitfall: Do not confuse atrial fibrillation dosing criteria with VTE treatment dosing. 4 The dose reduction criteria (age ≥80 years, weight ≤60 kg, serum creatinine ≥1.5 mg/dL requiring 2 of 3 criteria for 2.5 mg twice daily) apply ONLY to stroke prevention in atrial fibrillation, not to VTE treatment. 3, 5, 6
For VTE treatment, the standard 10 mg twice daily for 7 days followed by 5 mg twice daily should be used regardless of age or weight, unless severe renal impairment exists. 1, 2
Renal Impairment Considerations
Avoid apixaban in severe renal impairment (CrCl <15 mL/min), as patients with CrCl <25 mL/min were excluded from clinical trials. 1, 2
For patients with CrCl 15-25 mL/min, use with extreme caution and consider alternative anticoagulation (LMWH or unfractionated heparin). 1
Extended Treatment Beyond 6 Months
If extended anticoagulation is required beyond 6 months (for unprovoked VTE or persistent risk factors):
Option 1: Continue 5 mg orally twice daily for full therapeutic anticoagulation. 1
Option 2: Reduce to 2.5 mg orally twice daily for secondary prevention, which reduces bleeding risk while maintaining efficacy against recurrent VTE. 1, 3
The American Society of Hematology provides conditional recommendation that either standard dose (5 mg twice daily) or reduced dose (2.5 mg twice daily) may be used after 6 months, though the studies were not powered to directly compare these doses. 1
Hepatic Impairment
Avoid apixaban in patients with transaminases >2 times upper limit of normal or total bilirubin >1.5 times upper limit of normal, as these patients were excluded from clinical trials. 1, 2
Drug Interactions
Monitor for strong dual inhibitors of CYP3A4 and P-glycoprotein (e.g., ketoconazole, ritonavir), which may require dose adjustment or alternative anticoagulation. 4
Common Pitfalls to Avoid
Do not use prophylactic dosing (2.5 mg twice daily) for initial treatment of DVT—this is only for post-surgical prophylaxis or extended secondary prevention after completing initial treatment. 3
Do not apply atrial fibrillation dose reduction criteria to VTE treatment—these are separate indications with different dosing algorithms. 4, 5
Do not start with reduced intensity even in elderly or low-weight patients during the acute treatment phase—full VTE treatment dosing is required initially. 1, 2