Antiplatelets

Question 1

Aspirin

Answer 1

Cyclo-oxygenase Inhibitor / NSAID

Irreverisible inhibitor of COX-1
Reduced thromboxane A2 (TXA2)
Reduced platelet aggregation

Loading dose (300mg): acute coronary syndromes
Baby dose (75mg): non-analgesic effect

Question 2

Clopidogrel

Answer 2

Irreversible ADP receptor antagonist

Dual anti-platelet therapy

Inhibits ADP binding to P2Y12 receptors
Inhibits activation of GPIIb/IIIa receptors

Requires CYP2C19 for activation
Omeprazole & erythromycin inhibit CYP - reduces affect

Question 3

Prasugrel

Answer 3

Irreversible ADP receptor antagonist

Dual anti-platelet therapy

Inhibits ADP binding to P2Y12 receptors
Inhibits activation of GPIIb/IIIa receptors

Question 4

Ticagrelor

Answer 4

Rreversible ADP receptor antagonist

Dual anti-platelet therapy

Inhibits ADP binding to P2Y12 receptors
Inhibits activation of GPIIb/IIIa receptors

Question 5

Glycoprotein IIb/IIIa Inhibitor

Answer 5

Abciximab (i.v.)

Antibody that blocks binding of fibrinogen/vWF to GIIb/IIIa receptors

Question 6

Phosphodiesterase Inhibitors

Answer 6

Dipyridamole

Secondary prevention of TIA/stroke

Inhibits cellular reuptake of adenosine
^adenosine = inhibts platelet aggregation via A2 receptors

Question 7

Clot busters

Answer 7

Alteplase & Streptokinase

Increase plasminogen to plasmin (^fibrinolysis)

Streptokinase can only be used once as antibodies develop