Thrombolytics are medicines that may be used for the emergency treatment of an ischemic stroke (a stroke caused by a blood clot), a heart attack (myocardial infarction), or a massive pulmonary embolism (PE). They may also be used for other indications.
Thrombolytics break up clots by activating fibrinolysis and converting plasminogen to plasmin which lyses the clot. This allows blood and oxygen to reperfuse the area, limiting tissue damage. Thrombolytics are more effective if initiated as soon as possible after the event (such as a heart attack, stroke, or PE) but can be given within three hours of symptom onset for a stroke, or within 12-24 hours of symptom onset for a heart attack.
Major bleeding, including bleeding into the brain, is the most common risk associated with thrombolytics.