Pradaxa (dabigatran) blocks the activity of certain clotting substances in the blood. Pradaxa is used to reduce the risk of stroke and blood clots in people who have a medical condition called atrial fibrillation. Pradaxa is also used to treat blood clots in the veins of your legs (deep vein thrombosis, or DVT) or lungs (pulmonary embolism, or PE) and reduce the risk of them occurring again.