Anticoagulants Flashcards Preview

IPP/Drug Action > Anticoagulants > Flashcards

Flashcards in Anticoagulants Deck (17):
1

Haemostasis is a balance of

Thrombosis and bleeding

2

Bleeding defects can be caused by

Platelet defect or coagulating defects

3

Function of platelets

Clotting
Immune activation
Wound healing

4

Haemostasis mechanism

Reflex vasoconstriction to prevent further blood loss

Primary - thrombus formation (mainly consist of platelets) - occurs within 5 mins

Secondary - stabilisation of clot by fibrin (within 10 mins)

After formation of clot - retraction of clot to prevent occlusion

Both occur simultaneously

5

People with anaemia are more likely to have bleeding problems, why?

Normally platelets are pushed towards vessel walls due to RBCs (exacerbated in smaller vessels due to fahraeus effect) and hence platelets are less likely to encounter the vessel wall

6

EC normally secrete antithrombotic substances such as

PG, NO

7

Warfarin and heparin are

Anticoagulants

8

Antithombotic (antiplatelet) drugs

P2Y12 inhibitor - clopidogrel, prasugrel, tricagrelor (reversible)
Anti-thrombin III - binds to thrombin receptors PAR1/4
GPIIb/IIIa inhibitor - Abcitimab (mediates platelet aggregation)
COX inhibitor - aspirin (irreversible inhibition); blood thinning

9

Anticoagulants

Heparin and warfarin

10

Warfarin MoA

Vitamin K antagonist
Vit K is important in F2/7/9/10 PTM
Warfarin prevent PTM of these coagulating factor hence inhibiting clotting
Small therapeutic window and requires monitoring due to S ISOform metabolism. By CYP2C9 is sensitive to genetic variation

11

Heparin MoA

Binds to antithrombin III (natural inhibitor of thrombin and FXa)
Short half life
Reversible by giving protamine sulphate
Often surgery choice

12

P2Y12 binds to ADP and activate which G protein cascade to achieve what

Gi - decrease cAMP and facilitate aggregation

13

P2Y1 receptor is coupled to what receptor and results in what

Gq - PLC IP3 pathway which facilitates platelet shape change and aggregation

14

Activation of GPVI receptor on platelets activate

Dense tubular system which facilitates degranulatiin

15

LDL Contains apoprotein which is similar to what

Plasminogen

16

Why does hyperlipidaemia increase thrombosis risk?

1) atherosclerotic plaque formation 2) Apoprotiens are similar to plasminogen hence compete for receptor and decrease plasmin production

17

60-70% of circulating cholesterol is

LDL