Urokinase is effective for the restoration of flow to intravenous catheters blocked by clotted blood or fibrin (catheter clearance). Catheters are used extensively to administer treatments to patients for such purposes as dialysis, nutrition, antibiotic treatment and cancer treatment. Approximately 25% of catheters become blocked, meaning that affected patients cannot receive treatment until the catheter has been cleared or replaced. Urokinase is also used clinically as a thrombolytic agent in the treatment of severe or massive deep venous thrombosis, peripheral arterial occlusive disease, pulmonary embolism, acute myocardial infarction (AMI, heart attack), and occluded dialysis cannulas (catheter clearance). It is also administered intrapleurally to improve the drainage of complicated pleural effusions and empyemas. Urokinase is marketed as Kinlytic (formerly Abbokinase) and competes with recombinant tissue plasminogen activator (e.g., alteplase) as a thrombolytic drug.