Anticoagulants

Question 1

When would you use warfarin?

Answer 1

Warfarin is used in the long term to prevent venous thrombosis
It works by inhbiting the production of 2,7,9,10 clotting factors, which are vitamin K dependent.

Question 2

When would you use heparin instead of warfarin?

Answer 2

Heparin are used because they act rapidly, immediately, whereas warfarin takes some time to work because it is not acting on active clotting factors, it just prevents some from being made.

Question 3

When would you use low molecular weight heparin?

Answer 3

Used in a DVT, PE and AC, they are used unless fine control is needed, can be used in pregnancy.

Question 4

What is an example of an unfractionated heparin?

Answer 4

Heparin

Question 5

When wouldn’t you use a low molecular weight heparin and what would you use instead?

Answer 5

Wouldn’t use if you needed to use fine control, then you have to use unfractionated heparin.
An example of low molecular weight heparin is dalteparin and enoxaparin.

Question 6

What are the adverse reactions of dalteparin (low molecular weight heparin) and heparin (unfractionated heparin)?

Answer 6

Bruising and bleeding
Heparin induced thrombocytopenia
Rarely osteoporosis
Hypersensitivity

Question 7

What is used to reverse the effects of heparin?

Answer 7

Protamide sulfate

It can be given by injection into a vein

Question 8

What should you use to monitor warfarin and why?

Answer 8

INR which should normally be 1, this needs to be monitored because there is a risk of bleeding with warfarin.

Question 9

What is the preferred anticoagulant and how does it act?

Answer 9

Dalteparin

It is a low molecular weight heparin which acts straight away, it inhibit clotting factor 10a.

Question 10

What is the normal role of clotting factor 10a and what is it that inhibits this?

Answer 10

Clotting factor 10a normally converts (prothrombin) to thrombin (2a), low molecular weight heparin inhibit this clotting factor.

Question 11

Why is less monitoring required for dalteparin?

Answer 11

It doesn’t directly inhibit thrombin, therefore less likely to cause thrombocytopenia (low platelet count).

Question 12

What shouldn’t you give someone with NSAIDs and aspirin, in terms of anticoagulants?

Answer 12

Don’t give warfarin! As it is tightly bound to proteins it will displace NSAIDS.

Question 13

Give a new alternative therapy to warfarin and heparinises…

Answer 13

Direct acting Oral anticoagulants normally directly inhibit active clotting factor 10a
An example= apixiban.