Heparin - LMWH

Question 1

Give some examples of heparins

Answer 1

LMWH- Tinzaparin, Enoxaparin and Daltaparin

Fondaparinux

Question 2

How do heparins work?

Answer 2

Heparins bind to antithrombin III and activate it
Antithrombin III is responsible for the inactivation of Factor 10a and thrombin
UFH work to inactivate BOTH factor 10a and thrombin however LMWH work to preferentially inactivate factor 10a

Question 3

Which has more of a predictable effect LMWH or UFH?

Answer 3

LMWH as they preferentially inhibit factor 10a

Question 4

What are heparins used for?

Answer 4

1. FIRST LINE prophylaxis and treatment for VTE (along with warfarin to cover pro-coagulation phase while warfarin is not working)
2. FIRST LINE treatment for ACS (revascularisation and anticoagulation, given along with atiplatelets e.g. clopidogrel and aspirin)

Question 5

What are some contraindications of using heparin?

Answer 5

Bleeding disorders (thrombocytopenia and haemophilia)

Question 6

When should you use heparins with caution?

Answer 6

Pregnancy
Uncontrolled hypertension
Surgery/ trauma
Kidney insufficiency 
Peptic Ulcer/ Oesphageal varices
Hepatic Insufficiency

Question 7

What are some common interactions with warfarin?

Answer 7

Other anticoagulant/thrombotic drugs - use with caution unless required e.g. with warfarin for VTE
Antiplatlet drugs - use with caution unless required e.g. with aspirin/clopidogrel for ACS

Question 8

What are the common side effects of heparins?

Answer 8

Bleeding
Bruising
Heparin induced thrombocytopenia
Hypersensitivity reactions due to large molecules

Question 9

How are heparins excreted?

Answer 9

Renal Excretion

Question 10

How are heparins administered?

Answer 10

Subcutaneous

Question 11

How are heparins monitored?

Answer 11

APTR: aim for 1.5-2.5

Less required when using LMWH or fondaparinux