What laboratory tests are recommended before initiating apixaban (Eliquis) therapy?

From the Guidelines

Before starting Eliquis (apixaban), it is crucial to check renal function tests, liver function tests, complete blood count (CBC), and coagulation studies to ensure safe initiation and dosing of the medication. When considering the initiation of Eliquis, several key laboratory tests should be evaluated to minimize the risk of adverse effects and ensure the medication's efficacy. These tests include:

• Renal function tests (creatinine, BUN, and calculation of creatinine clearance) since Eliquis is partially eliminated by the kidneys, and significant renal impairment (CrCl <25 mL/min) is a contraindication 1.
• Liver function tests (ALT, AST, bilirubin) as hepatic impairment may affect drug metabolism, and active or clinically significant liver disease is a contraindication for Eliquis 1.
• A complete blood count (CBC) to assess baseline hemoglobin and platelet levels.
• Coagulation studies like PT/INR and aPTT should be obtained as baseline measurements, though Eliquis doesn't require routine coagulation monitoring. Additionally, a pregnancy test is necessary for women of childbearing age since Eliquis is contraindicated in pregnancy. For patients transitioning from warfarin to Eliquis, INR should be below 2.0 before initiating Eliquis 1. Regular monitoring of renal function is important during treatment, especially in elderly patients or those with compromised kidney function, as dose adjustments may be necessary if renal function deteriorates 1. It's also important to consider drug-drug interactions, especially with strong dual inhibitors/inducers of CYP3A4 and P-glycoprotein (P-gp), as they may affect Eliquis levels 1. The guidance from the NCCN guidelines insights: cancer-associated venous thromboembolic disease, version 2.2018, emphasizes the importance of careful patient selection and monitoring when initiating Eliquis 1.

From the Research

Laboratory Tests Before Eliquis (Apixaban)

To determine the necessary laboratory tests before initiating Eliquis (apixaban), several studies provide guidance:

• Coagulation tests that may provide qualitative assessment include:
  • Activated partial thromboplastin time
  • Prothrombin time
  • Thrombin time 2
• Methods with potential utility for quantitative assessment of DOACs include:
  • Plasma drug concentrations
  • Ecarin clotting time
  • Dilute thrombin time
  • Anti-factor Xa concentrations 2
• Noncoagulation laboratory monitoring should include:
  • Serum creatinine
  • Liver function tests
  • Complete blood counts 2

Renal Function and Eliquis

Studies have investigated the use of apixaban in patients with severe renal impairment:

• Apixaban may be a reasonable alternative to warfarin in patients with severe renal impairment 3, 4, 5, 6
• Patients with estimated glomerular filtration rate (eGFR) < 25 ml/min/BSA may benefit from apixaban therapy 3
• Apixaban has been shown to have a similar efficacy and somewhat superior safety profile compared to warfarin in patients with stage 4 or 5 chronic kidney disease (CKD) 5

Monitoring Frequency

The frequency of monitoring for patients on apixaban therapy:

• Should be 1-3 months after initiation and then at least every 6 months 2
• May require more frequent follow-up (i.e., 3 months) based on patient-specific characteristics such as age, renal impairment, hepatic impairment, and concomitant drug therapy 2