PAD and DVT Pharm

Question 1

Cilostazol indication and MOA

Answer 1

Indicated for claudication (leg pain while walking, experienced in DVT)

PDE3 inhibitor, prolongs life of cAMP in platelets

• prevents platelet aggregation
• vasodilation also

Question 2

Black box warning for Cilostazol

Answer 2

Contraindicated in pts with heart failure (decreased survival rates)

*PDE3 inhibitor that prevents platelet aggregation

Question 3

Heparin indication

unfractioned, LMW, fondaparinux

Answer 3

Used for rapid onset of anticoagulation (PE, stroke, DVT, DIC, acute MI)

*prevents formation of red clots

Question 4

What is the antidote for heparin (unfractioned)?

Answer 4

protamine

Question 5

How is heparin (all forms) administered?

Answer 5

IV or SC

Question 6

What are the risks/toxicities associated with unfractioned and LMW heparin?

Answer 6

Contraindicated in active bleed, thrombocytopenia, avoid use before surgery

*HIT

Question 7

Unfractioned heparin MOA

Answer 7

Activates antithrombin III, which inhibits factor Xa, and thrombin

Question 8

LMW heparin MOA

*Enoxaparin, Delteparin, Tinazeparin (-parin)

Answer 8

Activates antithrombin III, but can only inhibit factor Xa

Question 9

Fondaparinux MOA

Answer 9

Activates antithrombin III, but can only inhibit factor Xa

*synthetic pentasaccharide identical to binding structure of heparin

Question 10

Fondaparinux toxicities, noteworthy feature

synthetic Xa inhibitor (via ATIII

Answer 10

Excessive bleeding caused by fondaparinux is NOT reversible with protamine

*Fondaparinux also does not cause HIT

Question 11

Bivalirudin, Argatroban, Dabigatran MOA

Answer 11

Direct thrombin inhibitors (reversibly inhibit thrombin)

• bivalirudin has no antidote
• Argatroban binds catalytic site of thrombin

Question 12

What drug is used as prophylaxis and treatment of thrombosis in patients with HIT?

Answer 12

Argatroban (direct thrombin inhibitor)

Question 13

Warfarin MOA and effect

Answer 13

Inhibits vit K epoxide reductase, preventing conversion of vit K to its active reduced form

*decreases production of factors II, VII, IX, X, protein C, protein S

Question 14

Clinical application for warfarin

Answer 14

Long term prophylaxis of thrombosis

• especially for prevention of venous thrombosis in PE, mechanical heart valves, afib
• not useful in emergencies since effects are delayed
• goal INR is between 2-3

Question 15

Warfarin reversal in the event of bleeding

Answer 15

Vitamin K, blood products with coagulation factors

*fresh whole blood, plasma or plasma concentrates

Question 16

Why must heparin be started with warfarin when beginning long-term prophylaxis for thrombosis?

Answer 16

Short half life of protein C compared to other coagulation factors inhibited by warfarin

*creates pro-coagulant state that can lead to warfarin induced skin necrosis

Question 17

Rivaroxaban, Apixaban, Edoxaban MOA

Answer 17

Direct Xa inhibitors

Question 18

Direct Xa inhibitor effects

*Rivaroxaban, Apixaban, Edoxaban

Answer 18

Direct Xa inhibition directly inhibits the production of thrombin

*appears to be better than warfarin (rapid onset, fixed dosage, lower bleeding risk, fewer interactions, no INR monitoring)

Question 19

Clinical applications for Direct Xa inhibitors

*Rivaroxaban, Apixaban, Edoxaban

Answer 19

Same as warfarin, prevention of throbosis

Question 20

Antidote for Direct Xa inhibitors in the event of bleeding

*Rivaroxaban, Apixaban, Edoxaban

Answer 20

andexanet alfa

Question 21

Antidote for oral Direct thrombin inhibitors (dabigatran)

Answer 21

Idarucizumab