What is Pradaxa (Dabigatran)? Dabigatran is used to prevent stroke and harmful blood clots (such as in your legs or lungs) if you have a certain type of irregular heartbeat (atrial fibrillation). Pradaxa is also used to treat blood clots in the veins of your legs (deep vein thrombosis) or lungs (pulmonary embolism) and to reduce the risk of them occurring again. This medication may also be used to prevent these blood clots from forming after hip replacement surgery. Pradaxa is an anticoagulant that works by blocking a certain substance (a clotting protein called thrombin) in your blood. This helps to keep blood flowing smoothly in your body.