Mode of action of thrombolytics

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

Reference:

1. Muhammad U. Baig, Jeffrey Bodle. Thrombolytic Therapy. StatPearls Publishing 2024 Jan