Switching from Apixaban to Enoxaparin for Patients Unable to Take Oral Medications
Yes, you should switch patients who cannot tolerate oral medications from apixaban (Eliquis) to enoxaparin (Lovenox), as parenteral anticoagulation is necessary when oral administration is not feasible. 1, 2
Primary Indications for Switching
When patients are NPO (nothing by mouth) or unable to take oral medications due to nausea, vomiting, gastrointestinal dysfunction, or pre-procedural status, enoxaparin 1 mg/kg subcutaneously every 12 hours (or 1.5 mg/kg once daily) should be initiated. 1, 2 This is a straightforward clinical scenario where the oral route is unavailable, making parenteral anticoagulation the only viable option for maintaining therapeutic anticoagulation.
The American College of Cardiology specifically recommends enoxaparin for patients who cannot take oral medications, and this should be continued until oral therapy becomes feasible again. 1
Timing and Protocol for the Switch
Discontinue apixaban and wait approximately 12 hours before initiating enoxaparin, given apixaban's half-life of approximately 12 hours. 1, 2 This timing minimizes both the risk of subtherapeutic anticoagulation and excessive anticoagulation from overlapping agents.
For patients with normal renal function, you can start enoxaparin 12-24 hours after the last apixaban dose. 2 For patients with high thrombotic risk, ensure minimal gap in anticoagulation coverage during this transition. 2
Dosing Considerations
Standard Dosing
- For most patients <75 years with normal renal function: enoxaparin 1 mg/kg subcutaneously every 12 hours 2
- For patients ≥75 years: 0.75 mg/kg subcutaneously every 12 hours without an initial IV bolus 2
Renal Impairment Adjustments
For patients with creatinine clearance <30 mL/min, reduce enoxaparin to 1 mg/kg subcutaneously once daily (instead of twice daily). 1, 2 This is critical because both apixaban and enoxaparin are affected by renal function, but their dose adjustments differ. 2
Alternatively, for severe renal impairment, consider using unfractionated heparin instead of enoxaparin. 1
Critical Safety Warnings
Never administer enoxaparin and apixaban concurrently, as this significantly increases bleeding risk. 1, 2 This is one of the most important pitfalls to avoid during the transition.
Avoid switching back and forth between enoxaparin and apixaban or other anticoagulants unnecessarily, as repeated switches increase bleeding risk substantially. 2 Once you've made the switch to enoxaparin, maintain that therapy until the patient can reliably resume oral medications.
Monitoring During Transition
Monitor for signs of bleeding during the transition period, particularly in patients with renal impairment where closer monitoring is necessary. 2 For patients with severe renal impairment (CrCl <30 mL/min), obesity (BMI >40), low body weight (<50 kg), or age ≥70 years, consider monitoring anti-Xa levels targeting peak levels of 0.5-1.5 IU/mL measured 4-6 hours after the third or fourth dose. 1
When to Resume Apixaban
Once the patient can reliably take oral medications again, you can transition back to apixaban. 1 For uncomplicated cases in patients without cancer, with normal renal function (CrCl >30 mL/min), and ability to take oral medications, apixaban remains the preferred agent. 1
Special Populations
Cancer Patients
If your patient has active cancer (particularly gastrointestinal or genitourinary malignancies), consider continuing enoxaparin long-term rather than switching back to apixaban, as low molecular weight heparin is first-line therapy for cancer-associated thrombosis. 1 The National Comprehensive Cancer Network specifically recommends LMWH as first-line for cancer patients with VTE when CrCl is ≥30 mL/min. 1
Patients with Atrial Fibrillation
For patients on apixaban for stroke prevention in atrial fibrillation who temporarily cannot take oral medications, the same switching protocol applies, but aspirin alone is recommended only for patients who have permanent contraindications to oral anticoagulants, not for temporary NPO status. 3