Is there a laboratory test to check if Brilinta (ticagrelor) is at a therapeutic level?

Laboratory Testing for Ticagrelor Therapeutic Levels

There is no standardized laboratory test to check if Brilinta (ticagrelor) is at a therapeutic level in routine clinical practice. Unlike some other medications that require therapeutic drug monitoring, ticagrelor is typically administered at fixed doses without routine blood level monitoring.

Available Testing Options

While no standard therapeutic level test exists, several platelet function tests can indirectly assess ticagrelor's antiplatelet effects:

1. VerifyNow P2Y12 Assay

   • Most widely used test in clinical settings
   • Provides rapid assessment of P2Y12 receptor inhibition
   • Used in clinical trials like PLATO to measure ticagrelor's effects 1
   • Can confirm whether the drug is having its intended antiplatelet effect

2. Vasodilator-Stimulated Phosphoprotein (VASP) Phosphorylation Assay

   • More specialized test that measures P2Y12 receptor activity
   • Used alongside VerifyNow in clinical studies 1
   • Less commonly available in routine clinical settings

3. Platelet Aggregometry

   • Traditional method to assess platelet function
   • Can measure ADP-induced platelet aggregation
   • Less standardized for ticagrelor specifically

Clinical Considerations

• Ticagrelor is a direct-acting, reversible P2Y12 inhibitor that does not require metabolic activation, unlike clopidogrel 2, 3
• It has a more predictable antiplatelet effect than clopidogrel, with less variability between patients
• Unlike clopidogrel, ticagrelor does not have significant genetic variability issues that affect its efficacy 4
• The European Society of Cardiology notes that there is "no significant difference in efficacy and pharmacokinetics of ticagrelor between normal and obesity class 1" patients 4

When Testing Might Be Considered

While routine monitoring is not recommended, platelet function testing might be considered in specific situations:

• Suspected treatment failure (recurrent thrombotic events while on therapy)
• Major bleeding complications
• Before urgent surgery when ticagrelor reversal is being considered
• In patients with extreme body weights (very low or very high) 4
• When compliance is questionable

Reversal Considerations

If urgent surgery is needed or major bleeding occurs, bentracimab (a monoclonal antibody) has been shown to rapidly reverse ticagrelor's antiplatelet effects within 5-10 minutes, with effects sustained for more than 24 hours 1. The VerifyNow P2Y12 assay can be used to confirm reversal.

Practical Approach

• Focus on proper dosing (typically 90 mg twice daily) rather than blood level monitoring
• Ensure patient adherence to the twice-daily dosing schedule
• Be aware that ticagrelor has at least one active metabolite with similar pharmacokinetics to the parent compound 2
• Consider that ticagrelor may cause dyspnea and ventricular pauses as side effects, particularly in the first week of treatment 3

In summary, while specialized platelet function tests can assess ticagrelor's pharmacodynamic effects, there is no standard blood test to measure "therapeutic levels" of ticagrelor in routine clinical practice, and such testing is not typically recommended or necessary for most patients.