Anti-Thrombotics

Question 1

What is the MOA of aspirin?

Aspirin (NSAID)

Answer 1

Aspirin inhibits cyclooxygenase, preventing the production of prostaglandins from Arachidonic Acid.This prevents the release of thromboxane A2, which promotes platlet aggregation.

Question 2

What are the adverse effects associated with aspirin use?

Answer 2

1. Bleeding
2. Gastric ulcers

Question 3

What are the 3 glycoprotein IIB/IIIA inhibitors?

Answer 3

Abciximab
Tirofiban
Eptifibatide

ATE

Question 4

What is the general MOA for glycoprotein IIB/IIIA blockers?

Answer 4

They inhibit the binding of fibrinogen to the GP IIB/IIIA receptor, preventing the cross-linking of platelets and the formation of thrombi

Question 5

How does clopidogrel/ticlopidine inhibit platelet aggregation?

Answer 5

They prevent ADP from binding to their ADP receptor

Question 6

How does dipyridamole prevent platelet aggregation?

Answer 6

It inhibits the breakdown of cAMP, preventing the release of granules containing aggregating agents from the platelets

Question 7

Can heparin be given IM?

Answer 7

No; will cause hematomas

Question 8

Heparin binds to ________ and induces a ________, exposing its active site and increasing its ________ of clotting factors

Answer 8

Heparin binds to antithrombin III and induces a confirmational change, exposing its active site and increasing its rate of inactivation of clotting factors

Question 9

Must LMWH bind to factor X to inhibit it?

Low Molecular Weight Heparin

Answer 9

No. It is only necessary for heparin to bind AT III to inhibit factor X

Question 10

What are the clinical indications of heparin & warfarin?

Answer 10

1. DVT, pulmonary embolism & AMI
2. Combination with thrombolytics for revascularisation
3. Combination with GP IIb/IIIa inhibitors during angioplasty & coronary stents

Question 11

Which anticoagulant can be used during pregnancy?

Answer 11

Heparin or LMWH

Question 12

Which anticoagulant can be used in combination with GP IIb/IIIa inhibitors during angioplasty & coronary stenting?

Answer 12

Heparin

Question 13

What are the adverse effects of heparin?

Answer 13

1. Haemorrhage
2. Thrombocytopenia

Question 14

How to manage haemorrhage caused by heparin?

Answer 14

Stop heparin therapy + protamine sulfate

Question 15

________ can cross the placenta readily & cause haemorrhagic disorder in the fetus

Answer 15

Warfarin can cross the placenta readily & cause haemorrhagic disorder in the fetus

Question 16

Where is warfarin metabolised?

Answer 16

Undergoes hepatic metabolism by CYP450

Question 17

How is warfarin administered?

Answer 17

Oral

Question 18

Warfarin inhibits ________, preventing the formation of clotting factors II, ____, IX & ____

Answer 18

Warfarin inhibits vitamin K reductase, preventing the formation of clotting factors II, VII, IX & X

2, 7, 9, 10

Question 19

What are the adverse effects of warfarin?

Answer 19

Bleeding lol

Question 20

What DDIs are warfarin affected by?

Answer 20

Inhibitors/potentiators of CYP450

Question 21

What are the 4 thrombolytic agents?

Answer 21

1. Alteplase (t-PA)
2. Urokinase
3. Streptokinase
4. Anistreplase

Question 22

What is the MOA of the thrombolytics?

Answer 22

The thrombolytics activate plasminogen –> plasmin which then degrade the fibrin threads, helping to break down the thrombus

Question 23

What are the clinical indications for thrombolytic agents?

Answer 23

1. Emergency treatment of coronary artery thrombosis
2. Peripheral artery thrombosis & emboli
3. Ischaemic stroke (<4.5hr window)

Question 24

What is the limitation of thrombolytic drugs?

Answer 24

Limited window when it can be administered

Question 25

What are the adverse effects of thrombolytic drugs?

Answer 25

Bleeding lol

Question 26

When are thrombolytics contraindicated?

Answer 26

Pregnancy Healing wounds