Anti-platelets/Anti-coagulants

Question 1

What is aspirin used to treat - aside from pain?

Answer 1

CV disease (secondary prevention)
Management of NSTEMI and STEMI MI
Suspected/actual TIA
Ischaemic stroke
AF following disabling ischaemic stroke
Following coronary bypass surgery

Question 2

What are contra-indications to use of aspirin?

Answer 2

Active peptic ulceration
Bleeding disorders 
Children under 16 (Reye's syndrome)
Haemphilia
History of hypersensitivity to aspirin or any other NSAID

Question 3

Common side effects of aspirin?

Answer 3

Hypersensitivity
N&V
Tinnitus
Post-prandial Pain/discomfort in stomach or lower chest 
Cough/asthma exacerbation

Question 4

Indication for use of Warfarin?

Answer 4

VTE prophylaxis and treatment

Question 5

What are the contra-indications of warfarin?

Answer 5

Avoid use within 24 hours post partum
Haemorrhagic stroke
Significant bleeding

Question 6

What is the high level mechanism of action of Warfarin?

Answer 6

It is a Vitamin K Antagonist.
Blocks the action of Vit K
Slows down coagulation process

Question 7

Vitamin K reduces manufacture of a number of factors involved in the clotting cascade. Which ones are affected?

Answer 7

VII, IX and X

Question 8

What test is carried out to monitor warfarin levels?

Answer 8

INR
International normalized ratio
This is the prothrombin time

Question 9

What does the INR test measure?

Answer 9

Time it takes for blood to clot and compares it to the average.

Question 10

What is a normal INR for someone not on warfarin?

Answer 10

1.0

Question 11

What does a high INR signify?

Answer 11

The higher the INR the longer the time it takes to clot

Question 12

What is the full name of factor VII?

Answer 12

Proconvertin (Stable factor)

Question 13

What is the full name of factor IX?

Answer 13

Antihaemophilic factor B
Plasma thromboplastin component
Christmas factor

Question 14

What is full name of factor X?

Answer 14

Stuart-Prower factor

Question 15

What is Thromboxane?

Answer 15

An eicosanoid involved in platelet plug formation

Question 16

What are the two actions of Thromboxane?

Answer 16

Increases the ability of cells involved in clotting to stick together
Makes blood vessels smaller by vasoconstriction

Question 17

What two types of eicosanoids does aspirin affect?

Answer 17

It reduces levels of both Thromboxane and Prostacyclin

Question 18

How does aspirin in 75mg dose lead to an anti-platelet effect?

Answer 18

Reduces both Thromboxane/Prostacyclin
Prostacyclin can be made by endothelial cells whereas Thromboxane is made by platelets which have a 7-10 day lifespan so there is an anti-coagulant effect due to improved levels of prostacyclin at expense of thromboxane