Actilyse is a medication primarily used in the treatment of acute myocardial infarction (heart attack), acute massive pulmonary embolism, and acute ischemic stroke. Its active ingredient, alteplase, is a tissue plasminogen activator (tPA) that works by dissolving blood clots that have formed in blood vessels, thereby restoring normal blood flow. Actilyse functions by converting plasminogen to plasmin, the enzyme responsible for clot breakdown. This medication is typically administered intravenously in a hospital setting under close medical supervision due to the potential for serious side effects, including bleeding. It is crucial for Actilyse to be administered within a specific time frame from the onset of symptoms to be effective, highlighting the importance of prompt medical intervention in such emergencies.