Reteplase is a medication used to dissolve blood clots in patients experiencing a heart attack, specifically ST-elevation myocardial infarction (STEMI). It is a type of thrombolytic agent that works by breaking down fibrin, a protein that helps form clots, thereby restoring blood flow to the heart. Administered intravenously, reteplase is typically given in a hospital setting. Its use can significantly reduce the risk of heart damage and improve survival rates when given promptly after the onset of symptoms. However, it may not be suitable for everyone, and potential risks must be evaluated by healthcare professionals.