Antiplatelet And Fibrinolytic Drugs Flashcards
Describe a venous thrombosis
The thrombus has a high RBC and fibrin content
Low platelet content
Describe an arterial thrombosis
Occurs at the site of atherosclerosis following plaque rupture.
Lower fibrin count
Much higher platelet count than venous.
What type of cell releases prostacyclin?
Endothelial cells
How does prostacyclin inhibit platelet aggregation?
PGI2 binds to platelet receptors - increases cAMP in platelets - increased cAMP decreases calcium - prevents platelet aggregation - decrease in platelet aggregatory agents stabilises GP2a/3a receptors
What chemical mediators do activated platelets release?
TxA2
Serotonin
PAF
ADP
Platelet rich ‘white’ arterial thrombi get treated with what types of drugs?
Anti-platelet and fibrinolytic drugs
Lower platelet content ‘ red’ venous thrombi are treated with what types of drugs?
Parental anticoagulants - heparins
Oral anticoagulants - warfarin
What does aspirin inhibit
Cyclooxygenase
What is the result of inhibiting COX-1?
Thromboxane A2 is no longer formed from arachidonic acid.
Thromboxane is an aggregating agent
What can happen to the foetus if Aspirin is taken during the 3rd trimester of pregnancy?
It can cause premature closure of the ductus arteriosis
Why should aspirin not be taken in under 16 yrs?
Can cause Reyes Syndrome - swelling of the liver and brain.
Associated with chicken pox.
