Anticoagulant, Antiplatelet and Thrombolytic Drugs

Question 1

Describe the process of Haemostasis

Answer 1

vascular wall damage exposes collagen and tissue factor
primary haemostasis causes local vasoconstriction platelet adhesion activation and aggregation via fibrinogen
activation of blood clotting( coagulation) to form a stable clot by fibrin enmeshing platelets

Question 2

d: haemostasis

Answer 2

arrest of blood loss from a damaged vessel

physiological

Question 3

What is thrombosis?

Answer 3

pathological haemostasis

Question 4

d: thrombosis

Answer 4

haematological plug in the absence of bleeding

Question 5

Name the 3 predisposing factors that lead to thrombosis and what they are called collectively?

Answer 5

injury to vessel wall
abnormal BF
coagulability
Virchow’s Triad

Question 6

What colour is an arterial thrombus?

Answer 6

white

Question 7

what is an arterial thrombus treated with?

Answer 7

anti-platelets primarily

Question 8

What is a venous thrombus treated with?

Answer 8

anticoagulants

Question 9

What colour is a venous thrombus?

Answer 9

red

Question 10

What are anticoagulants mainly used for?

Answer 10

prevention and treatment of venous thrombosis and embolism

Question 11

Name the main Anticoagulant drugs

Answer 11

Warfarin
Heparin
Orally active Inhibitors

Question 12

What receptors does ADP bind to in Primary Haemostasis?

Answer 12

GPCR PURINE receptors

Question 13

How does warfarin work as an anticoagulant?

Answer 13

competes with vit K

this renders clotting factors II,VII,IX and X inactive

Question 14

where do arterial thrombus normally lodge?

Answer 14

left heart, carotid artery, brain

Question 15

where does venous thrombus normally lodge as an embolism/

Answer 15

lungs

Question 16

How is warfarin taken and it has a fast/slow onset of action?

Answer 16

orally

slow

Question 17

What is a risk of all anticoagulants?

Answer 17

haemorrhage

Question 18

do anticoagulants have a low/high therapeutic index? what does this mean?

Answer 18

low

therefore not that safe

Question 19

what is INR?

Answer 19

internalized normal ratio

used to check how fast blood is clotting under warfarin

Question 20

How is a warfarin overdose treated?

Answer 20

vitamin K

concentrate of plasma clotting factors

Question 21

How does Heparin work?

Answer 21

binds to anti-thrombin iii (inhibitor of coagulation) they inhibit factor Xa by binding to ATIII and Xa at the same time.

Question 22

How is Heparin administered?

Answer 22

either IV -immediate

or SC-delayed an hour

Question 23

What are some adverse effects of heparin?

Answer 23

haemorrhage
osteoporosis
hyperaldosteronism
hypersensitivity reaction

Question 24

What type of Heparins are preferred, why?

Answer 24

Low molecular weight Heparins

Question 25

What type of Heparins are preferred, why? How are they given?

Answer 25

Low molecular weight Heparins inhibit factor Xa, but not thrombin (IIa) SC

Question 26

When are LMWH not preferred?

Answer 26

renal failure

Question 27

Name 2 orally active inhibitors

Answer 27

Dabigatran | Rivaroxaban

Question 28

What does Dabigatran do?

Answer 28

direct inhibitor of thrombin

Question 29

What does Rivaroxaban do?

Answer 29

direct inhibitor of factor of Xa

Question 30

Name the 2 key antiplatelet drugs

Answer 30

Aspirin | Clopidogrel

Question 31

How does aspirin work?

Answer 31

irreversibly blocks COX in platelets, preventing TXA2 synthesis TXA 2 is responsible for activation of platelets

Question 32

How is aspirin given?

Answer 32

orally as thromboprophylaxis

Question 33

side effects of aspirin?

Answer 33

GI bleeding and ulceration

Question 34

How does Clopidogrel work?

Answer 34

inhibits P2Y12 receptor | Blocks binding of ATP to P2Y12 receptor which causes activation of platelets resulting in o fibril linking

Question 35

How is Clopidogrel given?

Answer 35

orally synergistic with aspirin

Question 36

What do the drugs that are fibrinolytics do?

Answer 36

used to reopen occluded arteries in acute MI or stroke but prefer PCI

Question 37

What is PCI?

Answer 37

percutaneous Coronary Intervention

Question 38

Name some fibrinolytics

Answer 38

streptokinase | alteplase and duteplase

Question 39

How does streptokinase work? And what is it?

Answer 39

protein extracted from cultures of streptococci

Question 40

What drug do you use for rapid anticoagulation?

Answer 40

warfarin and heparin together

Question 41

What drug do you use for less serious anticoagulation?

Answer 41

warfarin

Question 42

After 4 days of streptokinase why cant further doses not be given?

Answer 42

action blocked after 4 days by the generation of antibodies

Question 43

What does streptokinase do?

Answer 43

reduces mortality in MI but cation blocked after 4 days

Question 44

How does streptokinase work?

Answer 44

activates plasminogen | plasmin which breaks down the fibrin down to fragments lysing the clot

Question 45

side effects of Streptokinase?

Answer 45

may cause allergic reactions | and cant be used after 4 days

Question 46

How do alteplase and duteplase work?

Answer 46

Are recombinant tissue plasminogen activator (rt-PA)

Question 47

Why are alteplase and duteplase more effective on fibrin bound plasminogen than plasma plasminogen?

Answer 47

show selectivity for clots | no allergic reactions

Question 48

How Alteplase and duteplase given? Why?

Answer 48

IV | short half life

Question 49

Name the major adverse affects of fibrinolytics?

Answer 49

haemorrhage which may be controlled by oral tranexamic acid which inhibits plasminogen activation