Anticoagulants & Thrombolytics: Antiplatelet Agents Flashcards
Damaged vascular epithelium exposes
collagen and von Willebrand factor
Binding of von Willebrand factor to GP1b receptors activates
platelets
Activated platelet degranulation releases
- ADP
- 5-HT
- TXA2
Platelet degranulation releases ADP, 5-HT, and TXA2, stimulating
platelet aggregation
Adenosine diphosphate (ADP) binds to
the P2-Y12 receptor on platelets causing aggregation
Platelet degranulation releases serotonin, causing
platelet aggregation and vasoconstriction
Platelet degranulation releases TXA2, causing
platelet aggregation and activation as well as vasoconstriction
COX-1 synthesizes
prostanoids (e.g.prostaglandins, TXA2) within platelets
COX-2 expression is induced by
inflammation
COX-1 synthesizes TXA2 from
the precursor molecule arachidonic acid (AA)
Aspirin
- irreversibly acetylates COX-1 and COX2
2. irreversibly inhibits COX-1 and COX-2
Thienopyridines suffix
“-grel”
Thienopyridines are
ADP receptor inhibitors
Thienopyridines include
- Clopidogrel
- Trcagrelor
- Prasugrel
Thienopyridines
irreversibly bind to the P2Y12 ADP receptor preventing platelet aggregation
Aspirin pseudo allergy is due to
excess leukotriene synthesis (use clopidogrel instead)
Antiplatelet agents
reduce cardiovascular events in patients with peripheral artery disease
Antiplatelet agents include
- aspirin
- ADP receptor inhibitors
- Phosphodiesterase inhibitors
Use antiplatelet therapy (e.g. aspirin, ADP receptor inhibitors) in the setting of
MI and other acute coronary syndromes
Give chewable aspirin in setting of
acute MI
Dual antiplatelet therapy (i.e. aspirin and ADP receptor inhibitors) prevents
coronary stent thrombosis
Antiplatelet therapy (i.e. aspirin and ADP receptor inhibitors) prevents
ischemic stroke in patients with atherosclerosis and known cerebrovascular disease
Ticlopidine is an
ADP receptor inhibitor
Ticlopidine can cause
granulocytopenia