Antiplatelet, anticoagulant and thombolytic drugs

Question 1

Where would an arterial thrombus (white thrombus) become lodged?

Answer 1

Brain (stroke) or other organ

Question 2

Where would a venous (red thombus) become lodged?

Answer 2

Lungs (pulmonary embolus)

Question 3

In vivo pathway tissue factors

Answer 3

VIIa

Question 4

Contact pathway factors

Answer 4

XIIa and IXa

Question 5

X becomes Xa and what does this to?

Answer 5

Changes prothrombin (II) to thrombin IIa
this then converts fibrinogen to fibrin

Question 6

Xa inhibitor

Answer 6

Rivaroxiban

Question 7

Thrombin inhibitors

Answer 7

Dabigatran etexilate

Bivalirudin

Question 8

What state must vitamin K be in to act as an essential cofactor?

Answer 8

In its reduced form (hydroquinone)

Question 9

How does warfarin work?

Answer 9

Structurally similar to vitamin K, competes with vit. K for binding to vitamin K reductase

(prevents conversion of epoxide to hydroquinone)

Question 10

Which factors does warfarin inactivate?

Answer 10

II, VIII, IX and X

Question 11

Pregnancy, hypothyroidism and clotting factors?

Answer 11

Pregnancy = increased synthesis of clotting factors
Hypothyroidism = decreased degradation of clotting factors

Question 12

Treatment for overdose of warfarin?

Answer 12

Vitamin K or concentrate of plasma clotting factors

Question 13

Enoxaparin

Dalteparin

Answer 13

LMWH

Question 14

Name 2 LMWH

Answer 14

Enoxaparin

Dalteparin

Question 15

How is heparin administered?

Answer 15

IV or SC

Question 16

How are LMWH administered?

Answer 16

SC

Question 17

How do you determine optimum dosage for heparin?

Answer 17

In vitro clotting

Question 18

How are LMWH excreted?

Answer 18

Via the kidneys

Question 19

Heparin inhibits which factors?

Answer 19

IIa and Xa

Question 20

LMWH inhibits which factor?

Answer 20

Xa

Question 21

Adverse effects of heparin and LMWH?

Answer 21

Haemorrhage
Osteoporosis
Hypoaldosteronism
Hypersensitivity reactions

Question 22

Direct thrombin inhibitor

Answer 22

Dabigatran etexilate

Question 23

Factor Xa inhibitor

Answer 23

Rivaroxiban

Question 24

How are platelets cross linked?

Answer 24

Fibrinogen

Question 25

What are contained in platelet storage granules?

Answer 25

ADP, 5HT and coagulation factors

TXA2 is synthesised on demand by COX

Question 26

Blocks P2Y12 receptor

Answer 26

Clopidogrel

Question 27

Blocks IIb/IIa receptor

Answer 27

Tirofiban

Question 28

Blocks COX-1

Answer 28

Aspirin

blocks COX and so blocks TXA2 synthesis

Question 29

Aspirin side effects

Answer 29

GI bleeding and ulceration

Question 30

How is tirofiban administered?

Answer 30

IV

-used to prevent MI in high risk patients with unstable angina (with aspirin and heparin)

Question 31

Drugs which activate plasminogen? (plasminogen –> plasmin –> breaks up fibrin)

Answer 31

Streptokinase
Alteplase
Duteplase

Question 32

Why are alteplase and duteplase given IV?

Answer 32

Short half life

Question 33

Side effect of streptokinase?

Answer 33

Cause allergic reaction

Question 34

Reversing haemorrhage caused by fibrinolytics?

Answer 34

TRANEXAMC ACID (inhibits plasminogen activation)