Anticoag

Question 1

Heparin MOA

Answer 1

Binds to and activates antithrombin III, to inhib factor Xa and thrombin via ternary complex

Used for rapid onset anticoag effects in pulm embol, DVT, stroke, DIT and acute MI

Question 2

Heparin Kinetics

Answer 2

Given parenterally,
cant readily cross membranes (used in pregnancy)
requires intensive monitoring via aPTT

Question 3

Heparin Induce Thromboctopenia

Answer 3

Dev of IgG antibodies against heparin-bound platlet factor 4 PF4. Thei complex activates platelets leading to thombosis and thryombocytopenia. Higest rick in unfractioned heparin

Question 4

Enoxaparin, Dalteparin, Tinzaparin

Answer 4

Short length heparin molecule
Cannot form complex with antithrombin and thrombin
Inhibits Factor Xa
Given after ab surg, hip/knee replacement to prevent DVT

Question 5

Fondaparinux

Answer 5

Identical to antithrombin binding structure

Selectively inhibits factor Xa, activates antithrombin, prevents conversion of prothrombin to thrombin
treatment of pulm embol in conjuction with warfarin

admin subQ, not reversible with protamine

Question 6

Bivalirudin, Desirudin

Answer 6

Pepetide similar to Hirudin

Directly blocks thrombin (reversible)

Given with aspirin for Px undergoing coronary angioplasty

Doesn’t require antithrombin and cause less bleeding

Question 7

Argatroban

Answer 7

Directly binds to catalytic site of thrombin

Prophlyaxis and treatment of thrombosis in Px with heparin-induced TCP

Question 8

Warfarin MOA

Answer 8

Vit K antagonist (PO)

Decreases production of biologically active forms of Ca2+ dependent clotting factors II, VII, IX, and X also protein C and S

Used long term for prophylaxis of thrombosis (PE, thromboembolism with artificial heart valves, throbosis from Afib)

Not useful in emergencies

Question 9

Warfarin Kinetics

Answer 9

Contrainicated in thrombocytopenia, brain/eye/spine surgery, hemophila, ulcers

PO

eliminated by liver in bile

slow on and offset

Monitored with prothrombin time ration INR=2-3

Question 10

Rivaroxaban, Apixaban, eboxaban

Answer 10

Direct inhibitor of activaed factor X

Directly inhibits the production of thrombin

Rapid onset, fixed dosage, lower bleeding risk, fewer drug interactions, no need for INR monitoring

Prevents DVT and PE, prevents stroke and nonvalvular afib

PO

Unsafe in pregnancy

Question 11

Dibigatran

Answer 11

Reversible direct thrombin inhibitor

Same advantages over warfarin as rivaroxaban

contraindicated for those with mechanical heart valves

Pills are unstable

Idarucizumab is the antidote, not metabolized by CYP450

Question 12

Apirin

Answer 12

irreversibly blocks COX

Blocks formation of TXA2 which promotes platelet activation. Persists for the lifetime of the platelet

Question 13

Clopidogrel, Prasugrel, ticagrelor

Answer 13

Irreversible blockade of P2Y12 receptors on platlets, prevents its Gi protein driven decreases in platelet cAMP

Inhibits platelet aggregation

Prodrug must be activated by CYP2C19

Lower bleeding risk than aspirin.

Prasugrel=more effective with less drug interactions but more bleeding

Tica=reversible P2Y12 but increased risk of hemorrhagic stroke

Question 14

Cilostazol

Answer 14

type 3 phosphodiesterase inhibitor, prolongs the life of cAMP in platelets and cells

platelet aggregation inhibitor, vasodilator

Used in claudication

Question 15

Abciximab

Answer 15

Purified Fab frag

Blocks final common pathway or platelet ag. Inhibits ag caused by all factors

Most effective aniplatelet drug