Anticoagulant drugs

Question 1

What are indications for anticoagulant drugs?

Answer 1

Venous thrombosis

Atrial fibrilation

Question 2

Describe a venous thrombosis?

Answer 2

Low pressure system
Platelets not activated
Activates coagulation cascade - rich in fibrin clot

Question 3

Describe Heparin

Answer 3

Potentiates antithrombin
Immeadiate effect
Parenteral (iv or sc)
2 forms - unfractionated and low molecular weight (LMWH)

Question 4

How do you monitor the effects of Heparin?

Answer 4

Activated partial thromboplastic time (APTT) for unfractionated
Anti-Xa assay for LMWH but usually no monitoring of LMWH is required as more predictable response

Question 5

What are complications of Heparin?

Answer 5

Bleeding
Heparin induced thrombocytopenia (with thrombosis) HITT - monitor FBC in patients on heparin
Osteoporosis with long term use

Question 6

What can you give regarding complications of heparin?

Answer 6

Stop heparin (short t1/2)
Severe bleeding - Protamine sulphate

Question 7

What does Protamine sulphate do?

Answer 7

Reverses antithrombin effect

Complete for unfractionated and partial for LMWH

Question 8

Name 4 Coumarin anticoagulants and their mechanism of action

Answer 8

Warfarin
Phenindione
Acenocoumarin
Phenprocoumon
Inhibition of vitamin K

Question 9

Describe Vit K?

Answer 9

Fat soluble vitamin
Absorbed upper intestine
Requires bile salts for absorption
Final carboxylation of glutamic acid residues in clotting factors II, VII, IX and X

Question 10

What does Vit K add to clotting factors?

Answer 10

1 of the 2 COOH groups

Question 11

What does warfarin do?

Answer 11

Antagonism of Vit K

Question 12

How should warfarin be taken?

Answer 12

Same time everyday. recommended 6pm

Question 13

How is warfarin monitored?

Answer 13

INR levels

Question 14

How is INR worked out?

Answer 14

Patient’s PT in seconds over Mean normal PT in seconds

Question 15

What does INR stand for?

Answer 15

International Normalized Ratio

Question 16

What are mild bleeding complications? (3)

Answer 16

Skin bruising
Epistaxis
Haematuria

Question 17

What are severe bleeding complications? (3)

Answer 17

Gastro-intestinal
Intracerebral
Significant drop in Hb

Question 18

How can you reverse warfarin?

Answer 18

Administer Vit K

Administer clotting factors

Question 19

How long does Vit K take to work?

Answer 19

6 hours

Question 20

How long do clotting factors take to work?

Answer 20

Immediate

Question 21

Name one thrombin inhibitor?

Answer 21

Dabigatran

Question 22

Name 2 factor Xa inhibitors?

Answer 22

Rivaroxaban

Apixaban