Using Pradaxa - Coagulation tests

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Pradaxa does not need routine clinical monitoring, when used for either short- or long-term treatment.1 However, in cases of suspected overdose or in patients treated with Pradaxa presenting in emergency departments, certain tests can help in detecting the presence of Pradaxa and assessing the anticoagulation status of a patient treated with Pradaxa.

Prothrombin time (INR)

INR (Prothrombin time) is not sufficiently sensitive and is therefore not recommended2

The following tests can help to detect the presence of Pradaxa and assess the risk of bleeding:2

 

Thrombin Time (TT) and diluted Thrombin Time (dTT) – Quantitative and specific

The TT test measure will depend on the coagulometer and on the thrombin lot used for the measurement. It is therefore advisable to use the calibrated Hemoclot® Thrombin Inhibitor assay (a diluted TT [dTT] assay) with dabigatran standards to calculate the concentration of Pradaxa rather than to determine TT.2 Other dTT assays that provide a quantitative measure of Pradaxa plasma concentrations include HemosIL® and Technoclot.

  • A TT measure with the calibrated Hemoclot® Thrombin Inhibitor assay (HYPHEN BioMed, Neuville-sur-Oise, France) of >200 ng/mL dabigatran plasma concentration (approximately >65 seconds) prior to the next drug intake after 150 mg twice-daily dosing (trough measure, i.e. 10−16 hours after the previous dose) is associated with a higher risk of bleeding5,6
  • A normal TT measure indicates no clinically relevant anticoagulant effect of Pradaxa2

Activated Partial Thromboplastin Time (aPTT) - semi-quantitative, not specific

An aPTT test may be useful in determining an excess of anticoagulant activity, despite aPTT being less sensitive to the activity of Pradaxa above therapeutic levels. Please note: in the first 2–3 days after surgery, false prolonged measures may be detected.2,3

  • An aPTT 2–3 fold of control at trough (when the next dose is due) is associated with a higher risk of bleeding2,4

Ecarin clotting time (ECT) - Quantitative and specific

ECT provides a direct measure of the activity of direct thrombin inhibitors2

  • Approximately 3−4 times elevated ECT over control prior to the next drug intake of Pradaxa (at trough) is associated with a higher risk of bleeding7
References: 
  1. Pradaxa Summary of Product Characteristics 2016. Boehringer Ingelheim.
  2. van Ryn J et al. Thromb Haemost 2010;103:1116–1127.
  3. Liesenfeld K-H et al. Br J Clin Pharmacol 2006;62:527–537.
  4. Canadian Product monograph. Boehringer Ingelheim, 2010.
  5. Stangier J et al. Br J Clin Pharmacol 2007;64:292–303.
  6. Hemoclot® Thrombin Inhibitor assay (HYPHEN BioMed, Neuville-sur-Oise, France). www.hyphen-biomed.com.
  7. Boehringer Ingelheim. Data on file.