Anticoagulants

Question 1

How do AC work?

Answer 1

works by preventing thrombus formation

Question 2

What are the two categories of VTE?

Answer 2

DVT and pulmonary embolisms (all patients are assessed for VTE)

Question 3

Which patients are assessed for VTE?

Answer 3

1. > 60 years of age
2. Limited mobility
3. Obese
4. Malignant Disease
5. Thrombophilic disorder
6. History of VTE

Question 4

When are LMWH used?

Answer 4

general or orthopaedic surgery

Question 5

When are unfractionated LMWH used?

Answer 5

In patients who have renal failure

Question 6

Which patients use fondaparinux?

Answer 6

pts with hip or knee replacement surgery

DOAC’s are used for this too

Question 7

What are mechanical prophylaxis?

Answer 7

compression stockings

Question 8

Name a properties of Heparin.

Answer 8

Rapid onset of action but a short duration of action. (unfractionated)
Used in preference for patients at high risk of bleeding as its effect can be terminated quicker

Question 9

If patients are pregnant, which heparin is most suitable?

Answer 9

Heparin as it doesnt cross placenta, LMWH is preferred as it has a lower risk of osteoporosis and heparin induced thrombocytopenia

Question 10

Why is protamine used for?

Answer 10

to reverse effects of heparin in case of a haemhorrage

Question 11

What are S/E of heparin?

Answer 11

heparin induced thrombocytopenia and hyperkalaemia (especially in those with risk factors e.g. diabetic)

Question 12

Are LMWH heparins preferred over unfractionated heparins? Why?
examples?

Answer 12

Yes. Used in the prevention of VTE, tx of DVT and PE.

Examples: enoxaparin and tinzaparin - used OD - long duration of action

Question 13

What are OAC?

Answer 13

Warfarin, acenocoumarol, phenindione

Question 14

How does warfarin work? Whats it used for?

Answer 14

Antagonises the effects of vitamin K

Used for DVT, PE, AF

Question 15

How is the warfarin dose determined?

Answer 15

Based on patients INR

Question 16

What is INR?

Answer 16

high INR - blood is more ‘runny’ = at risk of bleeding

low INR - blood is less ‘runny’ - lower risk of bleeding

Question 17

How long does it take warfarin to work?

Answer 17

takes 48-72 hours for anticoagulant effect to develop

should be taken at the same time everyday so dose changes can be initiated immediately.

Question 18

What would you give for immediate effect whilst waiting for warfarin to have its own effects?

Answer 18

Given heparin concomitantly

Question 19

What are the target INR’s for which conditions?

Answer 19

2. 5 - DVT, PE, AF
3. 0 - mechanical aortic valves
4. 5 - recurrent DVT, PE, mechanical mitral valve

Question 20

When patient is starting on warfarin, how often is the INR measured?

Answer 20

daily or on alternate days but then will go on for weeks, but then 12 weeks

Question 21

What is the S/E of warfarin?

what is the antidote for warfarin?

Answer 21

haemorrhage

Vitamin K

Question 22

if a pt is undergoing elective surgery (pre-booked surgery), when should warfarin be stopped?

Answer 22

5 days before

Question 23

Whats the half life of warfarin and the new NOAC’s?

Answer 23

36 hours

NOAC - half life of 12 hours

Question 24

How are NOAC’s and warfarin cleared?

Answer 24

Warfarin - hepatic

NOACs - renal - contraindicated in patients with renal impairment

Question 25

How is stroke risk assessment and bleeding assessment made?

Answer 25

CHADSVASC

HASBLED

Question 26

which combination of drugs have a higher or lower risk of bleeding?

Answer 26

the risk of bleeding with aspirin and warfarin is less than that with clopidogrel and warfarin