mode of action of thrombolytics
Last reviewed 01/2018
All thrombolytics in use act as plasminogen activators:
- plasminogen is the inactive precursor of plasmin
- plasminogen and its natural activator, tPA, both bind to fibrin clots resulting in a cascade of local plasmin production
- streptokinase activates plasminogen throughout the circulation
- plasmin is a serine protease which is able to degrade fibrin, yielding soluble fibrin degradation products
Thrombolytics act at three sites:
- thrombus
- haemostatic plugs
- streptokinase produces a systemic impairment of haemostasis