Can anastrozole (Aromatase Inhibitor) and Eliquis (Apixaban) be taken together in a patient with a pulmonary embolism?

Anastrozole and Apixaban Can Be Safely Taken Together in a Patient with Pulmonary Embolism

Patients with pulmonary embolism can safely take anastrozole (an aromatase inhibitor) and apixaban (Eliquis) together, as there are no significant drug interactions between these medications that would compromise their efficacy or safety.

Anticoagulation for Pulmonary Embolism

First-line Treatment

• When initiating oral anticoagulation in a patient with pulmonary embolism (PE), a non-vitamin K antagonist oral anticoagulant (NOAC) such as apixaban is the recommended form of anticoagulant treatment 1
• Apixaban has been shown to be non-inferior to conventional therapy for preventing recurrent symptomatic venous thromboembolism (VTE) while causing significantly less major bleeding (RR 0.31; 95% CI 0.17–0.55; P < 0.001) 1

Duration of Treatment

• Therapeutic anticoagulation for at least 3 months is recommended for all patients with PE 1
• For patients with unprovoked PE or persistent risk factors, extended anticoagulation of indefinite duration should be considered 1
• After 6 months of therapeutic anticoagulation, a reduced dose of apixaban (2.5 mg twice daily) should be considered for extended treatment 1

Aromatase Inhibitors and Thrombotic Risk

While there has been some concern about thrombotic events with hormonal therapies:

• Aromatase inhibitors like anastrozole have generally been associated with a lower risk of venous thromboembolism compared to tamoxifen 2
• However, case reports suggest that thrombotic events can still occur in patients on aromatase inhibitors 2
• The incidence of venous thromboembolism with aromatase inhibitors may be higher than that expected in the general population, though lower than with tamoxifen 2

Management Considerations

Monitoring Requirements

• Regular assessment of drug tolerance, adherence, hepatic and renal function, and bleeding risk is recommended for patients on extended anticoagulation 1
• Routine clinical evaluation is recommended 3-6 months after acute PE 1

Potential Concerns

• While there are no direct contraindications to using anastrozole and apixaban together, patients should be monitored for:
  • Signs of recurrent VTE
  • Bleeding complications
  • Changes in renal or hepatic function that might affect apixaban metabolism

Follow-up Care

• An integrated model of care is recommended after acute PE to ensure optimal transition from hospital to ambulatory care 1
• For patients with persistent symptoms after PE treatment, evaluation for chronic thromboembolic pulmonary hypertension (CTEPH) should be considered, especially if there are mismatched perfusion defects on imaging studies 1

Conclusion

The combination of anastrozole and apixaban is appropriate for a patient with pulmonary embolism who requires both anticoagulation and aromatase inhibitor therapy. The benefits of treating both conditions outweigh potential risks, and there are no significant drug interactions that would preclude their concurrent use.