Pharm: Thrombolytic agents Flashcards
What is the function of plasmin?
Plasmin is the major fibrinolytic enzyme. Breaks down fibrinogen and fibrin.
What are the activators of plasmin?
t-PA, urokinase, streptokinase
Factor XIIa
What are the inhibitors of plasmin?
Aminocaproic acid
PAI-1, TAFI, alpha2 antiplasmin, alpha2 macroglobulin
What fragments are formed by plasmin degradation of stabilized fibrin?
Fragments X, Y, D and E
These products form D-dimers, hallmarks of DVT and DIC
What are the main factors that promote fibrinolysis?
Plasminogen content of clot
t-PA content/activity in and around clot
Protection of bound plasmin from antiplasmin
What are the factors that limit fibrinolysis?
Fibrin crosslinking by factor XIIIa
Antiplasmin content in and around fibrin clot
What are the main effects of thrombolytic therapy?
- Reduce thrombus size
- Reduce fibrinogen levels
- Increase fibrinogen and fibrin degradation products
- Antiplatelet activators
What are the 3 main categories of thrombolytic agents?
Urokinase
Streptokinase
Recombinant tissue plasminogen activators
What are the major recombinant tissue plasminogen activator drugs?
Alteplase, reteplase, and tenecteplase
How is thrombolytic therapy useful for MI patients?
Many MI patients have thrombi formed in the coronary vessels. Thrombolytic therapy is used to try to get rid of the fibrin-rich occlusion
How does time affect success of thrombolytic therapy?
Older clots are less susceptible to the lytic action of thrombolytic agents
Which thrombolytic agents are used for pulmonary embolism?
Streptokinase and urokinase
What complications are associated with thrombolytic therapy?
Bleeding, re-occlusion, stroke
What are the absolute contraindications of thrombolytic therapy?
Intracranial bleeding
Massive hemmorhage
What are the drug interactions with thrombolytic agents?
Antiplatelet drugs, heparins and dextrans
