Eliquis 2.5 mg Tablet is used to prevent and treat deep vein thrombosis (blood clots in leg veins) and pulmonary embolism (blood clots in the lung). Additionally, Eliquis 2.5 mg Tablet is used to prevent blood clots in patients with atrial fibrillation (irregular heartbeat). Deep vein thrombosis is a condition in which blood clots form in deep veins, usually in the legs. Pulmonary embolism is a condition in which a blood clot blocks the arteries in the lungs. Atrial fibrillation is a condition that causes irregular, often fast heartbeat.