Antiplatelets and Anticoagulants Flashcards Preview

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Flashcards in Antiplatelets and Anticoagulants Deck (25)
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1

How is arterial thrombosis managed?

Anti-platelets

2

How is venous thrombosis managed?

Anti-coagulants

3

What is the mechanism of action of aspirin?

Inhibits cyclo-oxygenase which is necessary to produce thromboxane A2

4

What are some of the possible side effects of aspirin?

Bleeding

Bronchospasm

5

What is the mechanism of action of clopidogrel and prasugrel? (anti-platelets)

ADP receptor antagonists

6

What is the mechanism of action of dipyridamole? (anti-platelet)

Phosphodiesterase inhibitor which reduces the production of cAMP which is a second messenger in platelet activation

7

What is the mechanism of action of abciximab? (anti-platelet)

GP IIb/ IIIa inhibitor which inhibits aggregation

8

How long before surgery should anti-platelets be stopped?

7 days prior to surgery

This is because anti-platelets affect platelet function for their life span which is 7 days long

9

Which drug is first line for acute thrombosis?

Heparin

*Has an immediate effect

10

How long is heparin given for after an acute incident?

6 months

Then switch to oral anticoagulants to avoid lifelong injections

11

What are the two forms of heparin?

Unfractioned

LMWH

12

How are the different forms of heparin monitored?

APTT - unfractioned

Anti-Xa assay - LMWH

13

What are some of the possible complications of heparin?

Bleeding

Heparin induced thrombocytopenia (HITT)

Osteoporosis (when used long-term)

14

How is heparin reversal achieved?

Stop the heparin

Protamine sulphate (if bleeding is severe)
- this binds to and turns off heparin

15

Give some examples of coumarin anticoagulants

Warfarin

Phenindione

Acenocoumarin

Phenprocoumon

16

What is the mechanism of action of the coumarin anticoagulants?

Inhibition of vitamin K

17

What is the mechanism of action of vitamin K?

Carboxylation of clotting factors

18

What factors are vitamin K dependent?

Factors II, VII, IX and X

Protein C and S

19

What is the mechanism of action of warfarin?

Blocks the ability of vitamin K to carboxylate clotting factors

20

How is warfarin therapy monitored?

INR

21

What are some of the possible complications of warfarin therapy?

BLEEDING:

Skin bruising

Epistaxis

GI bleeds

Intracerebral bleeds

22

How is warfarin reversal achieved?

Omit warfarin dose

Administer oral vitamin K

Administer clotting factors (FFP or factor concentrates)

23

What are the indications for use of the new anticoagulants?

Used instead of LMWH as prophylaxis in elective hip and knee replacement surgery

Used for selected patients for stroke prevention in AF

Used for treatment of DVT/ PE

24

What is the mechanism of action of dabigatran?

Directly inhibits thrombin

25

What is the mechanism of action of rivaroxaban and apixaban?

Xa inhibitors

(Xaban = Xa inhibitors)