DOAC Pharmacokinetics in Malabsorptive States

Direct oral anticoagulants, such as dabigatran, rivaroxaban, apixaban, and edoxaban, are becoming more popular for the prevention of stroke and treatment of venous thromboembolism, although their effectiveness relies on adequate gastrointestinal absorption. However, in the setting of malabsorption, such as after bariatric surgery, short bowel syndrome, or during the course of active inflammatory bowel disease, the pharmacokinetic profile of the drugs can be altered. Recent literature indicates that, although rivaroxaban and apixaban are effective in stable patients after bariatric surgery, such as sleeve gastrectomy or Roux-en-Y gastric bypass, dabigatran is not effective because it requires the acidic environment of the stomach for adequate absorption. However, in the setting of severe malabsorption, such as very short bowel syndrome, the gold standard, which is warfarin, is recommended because the effect of the drug can be monitored. Guidelines recommend avoiding the use of direct oral anticoagulants during the acute postoperative period, which is defined as 0-4 weeks, and using drug-specific assays, such as antiXa or dilute thrombin time, to ensure adequate absorption.