engleski

Presentation of the Patient with Low Peak Dabigatran Levels in Plasma Suggests the Importance of Quantitative Measurement of DOAC Drugs in Clinical Decision Making and Treatment

Background: In special clinical conditions quantitative measurement of direct oral anticoagulants (DOACs) in plasma, should be performed to help clinical decision making and treatment. Aims: To present a case report of a patient treated with dabigatran in whom low peak drug concentrations in plasma suggested inadequate anticoagulation. Methods: A 88 years old male was hospitalized due to recurrent symptoms of cerebral ischemia for last few days and brain ischemia was confirmed on CT scan. Before hospitalization, the patient was taking dabigatran (110 mg twice daily) due to persistent atrial fibrillation. Dabigatran was measured by Innovance DTI assay and rivaroxaban was measured by anti-FXa assay on BCSXP analyzer (Siemens Healthineers, Germany). The study was funded by the Croatian Science Foundation as a part of the research project IP-2016-06-8208. Results: Peak (two hours after the last dose) concentrations of dabigatran measured at three consecutive days were 35, 16 and 19 ng/mL, whereas trough (before the next dose) concentrations were and 34, <5 and 14 ng/mL, respectively. Low peak dabigatran concentrations obtained in three consecutive measurements suggested anticoagulation undertreatment that might result with embolic complications. This observation led to the decision to replace dabigatran therapy with rivaroxaban (1×20 mg/day). Measurement of rivaroxaban plasma levels after the second day of administration has shown both peak and trough rivaroxaban concentrations within expected therapeutic values i.e., 215 and 30 ng/mL, respectively. No new ischemic symptoms occurred and the patient was discharged home with rivaroxaban therapy. Results of laboratory testing are presented in Figure 1. Conclusions: Persistently low peak dabigatran concentrations could contribute to inadequate anticoagulation and consequent embolic complications in our patient. This case report strongly suggests the importance of quantitative measurement of DOACs levels in plasma in selected clinical conditions confirming as an effective approach in clinical decision making and treatment.

dabigatran concentration ; inadequate anticoagulation

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