What are the guidelines for switching from therapeutic heparin to apixaban (Direct Oral Anticoagulant)?

Guidelines for Switching from Therapeutic Heparin to Apixaban

When switching from therapeutic heparin to apixaban, discontinue heparin and begin apixaban at the usual time of the next scheduled dose of heparin, with no need for bridging or overlap between the two anticoagulants. 1

Dosing Recommendations

• For patients with venous thromboembolism (VTE), start apixaban at 10 mg twice daily for the first 7 days, followed by 5 mg twice daily for treatment of acute VTE 1
• For long-term prevention of recurrent VTE, use 2.5 mg twice daily after at least 6 months of treatment 1
• For patients with non-valvular atrial fibrillation, start with 5 mg twice daily, or 2.5 mg twice daily if the patient has at least two of the following: age ≥80 years, body weight ≤60 kg, or serum creatinine ≥1.5 mg/dL 1

Switching Protocol

• Discontinue heparin (unfractionated or low-molecular-weight) and begin apixaban at the time the next dose of heparin would have been administered 1
• No overlap period is required between heparin and apixaban, unlike when transitioning to warfarin 1, 2
• Avoid any gap in anticoagulation during the transition to prevent thrombotic complications 2

Special Considerations

• Monitor renal function before switching, as apixaban dosing may need adjustment in patients with renal impairment 1
• Be aware of potential drug interactions, particularly with combined P-glycoprotein (P-gp) and strong CYP3A4 inhibitors, which require dose reduction of apixaban 1
• For patients with heparin-induced thrombocytopenia (HIT), apixaban may be a suitable alternative, but should be initiated only after platelet count begins to recover 2, 3

Monitoring Requirements

• Unlike heparin, routine laboratory monitoring is not required for apixaban 1
• Be aware that apixaban can interfere with anti-Xa activity measurements if testing is performed for other reasons 2
• This interference can persist for up to 3 days after stopping apixaban, potentially leading to overestimation of heparin anti-Xa activity if switching back to heparin 2

Timing Considerations for Special Situations

• For patients requiring surgery or invasive procedures, apixaban should be discontinued at least 48 hours prior to procedures with moderate/high bleeding risk, or 24 hours prior to procedures with low bleeding risk 1
• For patients with epidural catheters, therapeutic anticoagulation must be administered with heparin to safely withdraw the catheter before switching to apixaban 2

Potential Pitfalls

• Avoid simultaneous administration of heparin and apixaban as this increases bleeding risk 4
• Do not start warfarin and apixaban simultaneously, as apixaban affects INR measurements 1
• For patients with active bleeding complications, apixaban should be held until hemostasis is achieved 4
• In patients with HIT, avoid early transition to vitamin K antagonists (warfarin) without coverage of a non-heparin anticoagulant like apixaban, as this may increase risk of thrombotic complications 5

By following these guidelines, clinicians can safely and effectively transition patients from therapeutic heparin to apixaban while maintaining adequate anticoagulation and minimizing risks of thrombotic or bleeding complications.