Anti-Coagulants/-Platelets

Question 1

What are the classes of anticoagulants?

Answer 1

Coumarins and heparins

Question 2

What is the mechanism of action of coumarins?

Answer 2

Antagonises vitamin K preventing y carboxylation of liver synthesised clotting factors II, VII, IX and X.

Question 3

Adverse effects of coumarin anticoagulation?

Answer 3

• Bleeding
• Paradoxical thrombosis
• Skin necrosis

Question 4

Contraindications to coumarin therapy?

Answer 4

• Recent surgery or bleeding
• Bleeding Diathesis
• Pregnancy

Question 5

What is the mechanism of action of the heparin anticoagulants?

Answer 5

Antithrombin III antagonist.

Decreased clotting factor activity.

Question 6

Side effects of heparin anticoagulants?

Answer 6

• Bleeding
• Osteoporosis
• Heparin-induced thrombocytopenia (less in LMWHs)

Question 7

Contraindications to heparin antigocoagulation?

Answer 7

• Recent surgery/bleeding
• Bleeding diathesis
• Thrombocytopenia
• Renal insufficiency (for LMWHs)

Question 8

What are the classes of anti platelets?

Answer 8

• Salicylates (e.g. aspirin)
• Thienopyridines (e.g clopidogrel)
• GPIIb/IIIa inhibitors (e.g. eptifibatide)

Question 9

What is the mechanism of action of salicylate anti platelet agents?

Answer 9

Irreversible acetylation of platelet COX1, preventing thromboxane A2 mediated platelet aggregation.

Question 10

Side effects of salicylate anti platelets?

Answer 10

• Bleeding
• GI upset/ulceration
• Impaired renal perfusion

Question 11

Contraindications salicylate Rx?

Answer 11

Active bleeding or PUD

Question 12

MoA thienopyridines (e.g. clopidogrel)?

Answer 12

Block platelet ADP receptors

Question 13

Adverse effects of thienopyridines (e.g. clopidogrel)?

Answer 13

• Bleeding
• Thrombotic thrombocytopenic purpura
• Neutropenia

Question 14

CIx thienopyridines (e.g. clopidogrel)?

Answer 14

Active bleeding of PUD