Background: Apixaban is one of recommended direct oral anticoagulants in the treatment of pulmonary embolism (PE), and this therapy is considered to be efficacious and safe. Although no therapeutic drug monitoring is recommended, there are no studies that measured apixaban concentrations in PE patients.
Aims: To measure and evaluate concentration variability of apixaban in serum during the trough phase after one month of stable therapy with recommended drug dosage.
Methods: This is a single-center retrospective cross-sectional study of PE patients who were discharged with apixaban in the therapy. After one month of stable therapy with 5mg of apixaban bid, during the expected trough phase of the drug concentration (15 minutes before the next dose of the drug) a blood sample from the cubital vein was taken for laboratory analysis. Trough apixaban plasma concentrations were measured by liquid chromatography-tandem mass spectrometry (LC-MS/MS). Basic patients’ characteristics were collected on the hospital admission for statistical analysis. Apixaban concentrations were presented in ng/ml and as median with interquartile range. Creatinine clearance was calculated using the Cockcroft-Gault equation. Recurrent PE or bleeding were one-month events of interest.
Results: Overall 22 patients in the period from 2019 till 2021 were included in the analysis (11 men and 11 women). The mean age and creatinine clearance were 61 years (SD=14) and 84 ml/min (SD=38), respectively. The median apixaban concentration in the trough phase with interquartile range (25th-75th percentile) was 220.78 (121.67 – 246.92). Minimal concentration was 57.67, and maximal was 2327.57 which was an outlier because the 90th percentile was at 358.25. No one-month event was noticed.
Conclusion(s): Apixaban concentrations measured in the trough phase in PE patients after one month of therapy were within a wide range of values. However, no recurrent PE or bleeding was noticed among this small group of PE patients.
To cite this abstract in AMA style:Dzudovic J, Dzudovic B, Crevar Sakac M, Obradovic S. Median serum trough concentration of apixaban in pulmonary embolism patients after one month of therapy [abstract]. https://abstracts.isth.org/abstract/median-serum-trough-concentration-of-apixaban-in-pulmonary-embolism-patients-after-one-month-of-therapy/. Accessed September 24, 2023.
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ISTH Congress Abstracts - https://abstracts.isth.org/abstract/median-serum-trough-concentration-of-apixaban-in-pulmonary-embolism-patients-after-one-month-of-therapy/