Antithrombotic Agents/Coagulation Flashcards
What triggers intrinsic clotting cascade? What factors are involved in Intrinsic cascade?
Endothelial damage. 12, 11, 9, 10
What triggers extrinsic clotting cascade? What factors are involved?
Vessel/extravascular tissue damage. 7, 10
What factors are common to both pathways?
Xa, 5a (converts prothrombin to thrombin)
What are inhibitors of clotting cascade?
Protein C/S (inhibit 8 and 5), Tissue factor pathway inhibitor (inhibits 7A-TF complex), Antithrombin III (inhibits protease, 10, 2)
How long do platelets circulate? What kind of thrombi are they found in?
7-10 days. Arterial only (not venous)
What’s MOA of aspirin? What effect does it have on CV dz?
Irreversible COX1 inhibitor at low dose, COX2 inhibitor at high dose (>1g/day). 25% mortality reduction from CV
What’s MOA of dipyridamole? When is it used?
inhibit PDA and adenosine deaminase->decrease plt aggregation/thrombosis. VTE ppx after valve replacement with coumadin 75-100 mg QID
What’s MOA of cilostazol? What are contraindications? How long do you take it for claudication?
PDE3 inhibitor -> decrease smooth muscle contractility, inhibit plt aggregation. Avoid grapefruit, CI in heart failure. 6-12 weeks to see effectiveness
How do P2Y12 inhibitors work? What’s score for PRU?
Inhibit P2Y12 -> inhibit ADP binding -> unable to stimulate platelet aggregation. PRU>235 indicates high likelihood of resistance
How is clopidogrel activated?
Metabolized/activated by hepatic CYP 2C19
What’s dose of Prasugrel?
Loading 60 mg, maintenance 10 mg daily (5 mg daily if <60kg)
What’s different about mechanism of Ticagrelor? What’s dose?
Binds P2Y12 but not at the ADP binding site. Loading 180 mg, 90 mg BID x 1y then 60 mg BID
What’s an IV P2Y12 inhibitor? What’s dose?
Cangrelor. Loading: 30 mcg/kg IV bolus, Maintenance: 4 mcg/kg/min.
What’s MOA of Tirofiban? What’s dose?
Reversible competitive inhibitor of GP IIb/IIIA receptor. Loading 25 mcg/kg IV, infusion 0.15 mcg/kg/min
What’s MOA of Eptifibatide? What’s dose?
Blocks fibrinogen/vWF binding to GP IIb/IIIA on platelet surface. 180 mg/kc IV bolus, maintenance 2 mcg/kg/min