anticoagulant drugs

Question 1

which factor in the coagulation cascade is known as ‘prothrombin’?

Answer 1

factor II

Question 2

what is haemostasis?

Answer 2

the arrest of blood loss from damaged blood vessels via vascular constriction, formation of platelet plug, formation of a blood clot, growth of fibrous tissue

Question 3

what reaction does THROMBIN initiate (acting as an enzyme in the coagulation pathway)?

Answer 3

the cleavage of fibrin from fibrinogen - fibrin is the ‘sticky’ protein which creates clots

Question 4

what is the role of vitamin K in blood coagulation?

Answer 4

acts as a co-factor for the post-translational modification of factors II, VII, IX and X

Question 5

what drug is an antagonist of vitamin K which can competitively inhibit the vitamin K reductase enzymes?

Answer 5

warfarin

Question 6

how is warfarin administered?

Answer 6

orally

Question 7

how long does warfarin take to act?

Answer 7

12-20 hours

Question 8

why does warfarin take so long to act?

Answer 8

because the factors that already exist need to be degraded

Question 9

what is the main side affect of warfarin?

Answer 9

haemmorrage

Question 10

what calculation is used to monitor patients who have taken warfarin?

Answer 10

prothrombin time

Question 11

what factors can increase the effects of warfarin?

Answer 11

decrease availability of vitamin K
give broad spectrum antibiotics
liver disease

Question 12

how does heparin act?

Answer 12

acts as a ‘scaffold’ to bring antithrombin III (an enzyme inhibitor) into contact with enzymes of the coagulation pathway - accelerates the rate of inhibition

Question 13

how is heparin administered?

Answer 13

Intravenously

Question 14

which anticoagulant drug is taken orally and directly inhibits factor Xa (acts to catalyse transformation of prothrombin to thrombin)?

Answer 14

rivaroxaban/apixaban

Question 15

is rivaroxaban reversible?

Answer 15

no!

Question 16

do you need to monitor rivaroxaban like you would with warfarin?

Answer 16

no

Question 17

what is the name of the synthetic version of vitamin K which can be given to outcompete warfarin?

Answer 17

menadiol sodium phosphate

Question 18

what are the two anti platelet agents?

Answer 18

aspirin and clopidogrel

Question 19

which drug acts via inhibition of cyclooxegenase?

Answer 19

aspirin

Question 20

which drug acts on P2Y12ADP receptors to prevent platelet aggregation?

Answer 20

clopidogrel

Question 21

what are the two fibrinolytic drug?

Answer 21

alteplase and sreptokinase

Question 22

how is a thrombus broken down?

Answer 22

by cleavage of plasmin from plasminogen. Plasmin reads down fibrin

Question 23

which drug stimulates the breakdown of thrombi and acts more potently on fibrin-bound plasminogen?

Answer 23

Alteplase

Question 24

which fibrinolytic drug is non-enzymatic and non-selective plasminogen activator?

Answer 24

streptokinase