Anti-platelet drugs Flashcards
what happens when atherotic plaques rupture
platelets are recruited causing thrombosis
MI, stroke, unstable angina (ischaemia and infarction)
how do platelets aggregate
release granules - ADP, thromboxane A2
via membrane glycoproteins
risk factors for arterial thrombosis
hypertension
smoking
high cholesterol
diabetes
how do platelets bind to subendothelial collagen
glycoprotein 1b and VWF
how do platelets attach to each other
fibrinogen
GPIIbIIIa
how does aspirin work
inhibits cyclo-oxygenase (necessary to produce thromboxane A2
side effects of aspirin
bleeding
blocks production of prostaglandins (GI ulcers, bronchospasm)
how does clopidogrel work
ADP receptor antagonist
blocks ADP so less aggregation
how does dipyridamole work
phosphodiesterase inhibitor - reduces cAMP production (used in platelet activation)
examples of GPIIb/IIa inhibitors and what is its action
abciximab
inhibits aggregation
when should anti-platelet drugs be stopped and why
affect platelet function for their entire 7-10 day life span
stop agents 7 days before surgery to reduce risk of bleeding
how can anti-platelet drugs be reversed if severe bleeding
platelet transfusion
