MW: 6968,55 Da. Hirudin is a direct action anticoagulant decreasing the activity of thrombin in blood. Anticoagulants are used in the therapy of myocardium and lung infarct, thrombocytic and embolic insults, thrombophlebitis and others, as well as in the preventive treatment of atherosclerosis of coronary arteries, brain vessels, rheumatoid mitral valve diseases. In surgery it is used to prevent thrombus formation during the post-operative period. This protein is from Hirudo medicinalis.