Can a Patient Get a Blood Clot on Eliquis?
Yes, patients can develop thromboembolism while taking Eliquis (apixaban), though the risk is significantly reduced compared to no anticoagulation. No anticoagulant provides 100% protection against clot formation, and breakthrough thrombotic events occur even with appropriate dosing 1, 2.
Risk of Breakthrough Thrombosis on Apixaban
In the AMPLIFY trial evaluating apixaban for acute VTE treatment, recurrent VTE or VTE-related death occurred in 2.3% of patients receiving apixaban over 6 months, demonstrating that breakthrough events do occur despite therapeutic anticoagulation 2.
For atrial fibrillation stroke prevention, apixaban was noninferior or superior to warfarin in preventing stroke or thromboembolism, but breakthrough events still occurred in both treatment arms 3.
The ARISTOTLE trial showed that while apixaban reduced stroke and systemic embolism compared to warfarin, complete elimination of thrombotic events was not achieved 3.
High-Risk Situations for Breakthrough Thrombosis
Patients with triple-positive antiphospholipid syndrome should not receive apixaban, as DOACs including apixaban are associated with increased rates of recurrent thrombotic events compared to vitamin K antagonists in this population 1.
Inappropriate Dosing Increases Risk
Underdosing apixaban significantly increases thrombotic risk 3. Thromboembolic events during hospitalization occurred specifically in underdosed patients in observational studies 3.
Common reasons for inappropriate underdosing include: misapplication of dose-reduction criteria, continuation of incorrect home doses, and dosing errors by prescribers 3.
Apixaban requires dose reduction to 2.5 mg twice daily only when at least 2 of the following criteria are met: age ≥80 years, body weight ≤60 kg, or serum creatinine ≥1.5 mg/dL 1. Using only one criterion results in inappropriate underdosing 3.
Renal Impairment Considerations
Apixaban should be avoided in patients with severe renal impairment (CrCl <15 mL/min) or end-stage renal disease on dialysis, as drug accumulation and unpredictable anticoagulant effects may occur 3.
Patients with CKD on dialysis accumulate apixaban, and appropriate dosing in this population remains uncertain despite some evidence suggesting standard-dose apixaban (5 mg) may provide better stroke/embolism protection than low-dose (2.5 mg) 3.
Cancer-Associated Thrombosis
In cancer patients with VTE, apixaban showed efficacy in the AMPLIFY trial, but only 2.7% of enrolled patients had cancer, limiting generalizability 3.
Cancer patients have higher baseline VTE recurrence risk, and while apixaban reduces this risk, breakthrough events remain a concern particularly in high-risk malignancies like pancreatic cancer 3.
Clinical Scenarios Requiring Heightened Vigilance
Perioperative Period
Premature discontinuation or delayed resumption of apixaban after surgery increases thrombotic risk 1. For high bleeding-risk procedures like cervical fusion, apixaban should be resumed 24-72 hours postoperatively once hemostasis is confirmed 4.
Bridging with parenteral anticoagulation is generally not recommended during brief interruptions of apixaban, as it does not improve outcomes and increases bleeding risk 3.
Mechanical Heart Valves
- Apixaban is contraindicated in patients with mechanical heart valves based on the RE-ALIGN trial showing increased thrombotic events with DOACs in this population 3, 1.
Monitoring Limitations
Standard coagulation tests (PT, INR, aPTT) do not reliably correlate with apixaban levels and cannot be used to assess anticoagulant effect or predict thrombotic risk 1, 5.
Anti-factor Xa activity testing is not useful for monitoring apixaban's anticoagulation effect 1.
Key Pitfalls to Avoid
Never assume apixaban provides complete protection against thrombosis—counsel patients about warning signs of VTE (leg swelling, chest pain, shortness of breath) 1.
Verify correct dosing criteria are met before prescribing reduced-dose apixaban (2.5 mg twice daily), as inappropriate underdosing is a common cause of breakthrough thrombosis 3.
Assess for triple-positive antiphospholipid syndrome before initiating apixaban, as these patients require vitamin K antagonist therapy instead 1.
Ensure medication adherence, as missed doses rapidly diminish anticoagulant effect given apixaban's 12-hour half-life 3.