- Dabigatran is a direct inhibitor of thrombin that has recently been approved for primary and secondary stroke prevention and prevention of systemic embolism in patients with atrial fibrillation. The RE-LY (Randomized Evaluation of Long Term Anticoagulant Therapy [with Dabigatran Etexilate]) study showed that dabigatran given at a dose of 110 mg twice a day (bid) was associated with rates of stroke and systemic embolism that were similar to those associated with warfarin (International Normalized Ratio target 2.0-3.0), and lower rates of major hemorrhage. Dabigatran administered at a dose of 150 mg bid was significantly more effective compared with warfarin and showed a similar rate of major hemorrhages. Both dosages resulted in an approximately 60% to 70% relative reduction of intracranial hemorrhage. The dosage of 110 mg bid should be preferably used in patients older than 75 years at a higher bleeding risk. The Hemoclot (Hyphen BioMed, Mason, OH) test to measure dabigatran serum concentration is commercially available, but presence of the drug may also be detected using the activated partial thromboplastin time or thrombin time.