Urokinase is primarily used in the medical field as a thrombolytic agent to dissolve blood clots. It is commonly administered in the treatment of acute pulmonary embolism, deep vein thrombosis, and arterial occlusions. The enzyme works by converting plasminogen into plasmin, which then breaks down fibrin clots, helping to restore blood flow. It is also utilized in certain cardiac conditions, such as myocardial infarction, to clear blocked coronary arteries. Additionally, urokinase finds application in catheter clearance, where it helps to dissolve fibrin deposits that may obstruct intravenous or dialysis catheters. Its ability to effectively target clots makes it a valuable tool in emergency and critical care settings.