Should I adjust the dose of Eliquis (apixaban) in an elderly male with anemia and thrombocytopenia?

Apixaban Dose Adjustment for Elderly Male with Anemia and Thrombocytopenia

For an elderly male with hemoglobin 9.9 g/dL and platelet count of 131 × 10^9/L on apixaban 5 mg twice daily, dose reduction to 2.5 mg twice daily is recommended due to the increased bleeding risk associated with thrombocytopenia and anemia.

Assessment of Current Clinical Situation

• The patient has moderate thrombocytopenia (platelet count 131 × 10^9/L) and anemia (Hgb 9.9 g/dL), which increases the risk of bleeding while on full-dose anticoagulation 1
• Current dose of apixaban is 5 mg twice daily, which is the standard dose for most patients 2
• Thrombocytopenia is a significant concern when managing anticoagulation therapy, as it increases bleeding risk 1

Apixaban Dosing Considerations

• According to FDA labeling, apixaban dose reduction to 2.5 mg twice daily is recommended for patients with at least two of the following: age ≥80 years, body weight ≤60 kg, or serum creatinine ≥1.5 mg/dL 2
• While the patient's platelet count (131 × 10^9/L) is above the severe thrombocytopenia threshold (<50 × 10^9/L), the combination of moderate thrombocytopenia and anemia increases bleeding risk 1
• Inappropriate dosing of direct oral anticoagulants (DOACs) is common, with underdosing occurring in 4.7% to 26.1% of patients and overdosing also being problematic 1

Evidence-Based Recommendations for Thrombocytopenia

• For patients with platelet counts ≥50 × 10^9/L, full therapeutic anticoagulation is generally considered safe 1
• However, the combination of anemia and thrombocytopenia significantly increases bleeding risk 1
• In patients with cancer-associated thrombosis and moderate thrombocytopenia (platelet count between 25-50 × 10^9/L), dose reduction to 50% of therapeutic dose is recommended 1
• While the patient's platelet count is higher (131 × 10^9/L), the presence of anemia (Hgb 9.9 g/dL) compounds the bleeding risk 1

Recommended Approach

1. Reduce apixaban dose to 2.5 mg twice daily 1, 2

   • This adjustment balances thrombotic protection while reducing bleeding risk
   • Closely monitor for signs of bleeding or thrombosis

2. Implement more frequent monitoring 1

   • Complete blood count every 2-4 weeks to monitor hemoglobin and platelet trends
   • Monitor for signs and symptoms of bleeding

3. Consider underlying causes 1

   • Evaluate for potential causes of thrombocytopenia and anemia
   • Rule out heparin-induced thrombocytopenia if patient has had recent heparin exposure 3, 4

Important Considerations and Caveats

• If platelet count drops below 50 × 10^9/L, further dose adjustment or temporary discontinuation may be necessary 1
• Bleeding risk with apixaban shows a U-shaped relationship with BMI, with increased risk at both extremes of weight 1
• Concomitant medications that affect P-glycoprotein or CYP3A4 may alter apixaban levels and should be reviewed 1
• While some evidence suggests DOACs may be used in thrombocytopenia, most studies focus on cancer-associated thrombosis rather than general medical patients 1, 5

Follow-up Recommendations

• Reassess complete blood count in 2-4 weeks 1
• If platelet count falls below 50 × 10^9/L, consider further dose reduction or temporary discontinuation 1
• If bleeding occurs despite dose reduction, consider temporary discontinuation of anticoagulation 1
• Investigate underlying causes of cytopenias if not already known 1