Week 9

Question 1

Extrinsic coagulation cascade

Answer 1

driven by injury of endothelium

Question 2

major factors involved in extrinsic cascade

Answer 2

III, VII, IV

Question 3

intrinsic coagulation cascade

Answer 3

changes in the phospholipid membrane

Question 4

majro factors involved in extrinsic cascade

Answer 4

XII, XI, IX, VIII

Question 5

point of convergence between extrinsic and extrinsic coagulation cascade

Answer 5

X and V in presence of phospholipids and CA forming complex turning prothrombin into thrombin

Question 6

effect of thrombin

Answer 6

turns fibrin into fibrinogen

Question 7

what is a zymogen

Answer 7

inactive precursor of an enzyme

Question 8

what drives Heamostasis

Answer 8

mechanical injury- damage of blood vessel- clot forms

Question 9

waht drive Thrombosis

Answer 9

other forms of vascular damage leading to paltelt activation and occlusion

Question 10

what is atherotrhombosis

Answer 10

atherosclerotic plaque forms and occludes- lots of lipids

Question 11

What does Warfarin treat

Answer 11

Venous thrombosis
Atrial fibrillation
Recurrant MI

Question 12

action of warfarin

Answer 12

Inhibits hepatic synthesis of vitamin K dependent coagulation factors II, VII, IX and X by inhibiting vitamin K reductase

Question 13

factors casuing graet effect of warfarn

Answer 13

Oral bioavialbility almost 100%
Almost 99% bound to plasma protein
Stays in boyd for 5-7 days

Question 14

How do S and R warfarin differ

Answer 14

S-warfarin is much more efficient inhibitor of VKOR- mostly eliminated by CYP2C9
R- warfarin less effective- broken down by CYP1A1 and other enzymes

Question 15

1/1 CYP2C9 and efect on warfarin

Answer 15

(high CYP2C9 activity)

need much higher dose- more s- warfarin broken down

Question 16

3/*3 CYP2C9 and efect on warfarin

Answer 16

much lwer dose as cytochrome enzyme does not eliminate well so mire S-warfarin

Question 17

How would you perform a PT assay

Answer 17

Activate coagulation cascade and measure how long it takes for fibrin clot to form telling us how responsive it is

Question 18

what is INR

Answer 18

international normalized ratio-

Question 19

hwo to calculate INR

Answer 19

INR=(patient PT/ control PT)

Question 20

dosing of warfarin with INR less than 2

Answer 20

increase weekly dose by 5-20%

Question 21

dosing of warfarin INR of 3-3.5-

Answer 21

decrease weekly dose 5-15%

Question 22

dosing of warfarin INR3.6-4

Answer 22

withhold no dose to one dose- deceased weekly dose by 10-15%

Question 23

dosing of warfarin INR graeter than 4

Answer 23

withhold no dose or one dose- decrease weekly dose by 10-20%

Question 24

guidelines for warfarin non african descent

Answer 24

cacluate dose using pharmacogenetic algorithm

Question 25

guidlines for warfarin of african descent

Answer 25

*5 *6 *8 and *11 important for dosing and calculate using algorithm if this information isn’t available

Question 26

Below INR of 1

Answer 26

high risk of clot

Question 27

INR above 5

Answer 27

massive increase of risk of bleeding

Question 28

effect of CYP2C9 *2 and *3

Answer 28

decreased warfarin clearance

Question 29

percentage with sensitive or highly sensitive response tow warfarin

Answer 29

6-8% sensitive and 4% highly sensitive

90% normal response