Anticoagulants Flashcards
(26 cards)
How do AC work?
works by preventing thrombus formation
What are the two categories of VTE?
DVT and pulmonary embolisms (all patients are assessed for VTE)
Which patients are assessed for VTE?
- > 60 years of age
- Limited mobility
- Obese
- Malignant Disease
- Thrombophilic disorder
- History of VTE
When are LMWH used?
general or orthopaedic surgery
When are unfractionated LMWH used?
In patients who have renal failure
Which patients use fondaparinux?
pts with hip or knee replacement surgery
DOAC’s are used for this too
What are mechanical prophylaxis?
compression stockings
Name a properties of Heparin.
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
If patients are pregnant, which heparin is most suitable?
Heparin as it doesnt cross placenta, LMWH is preferred as it has a lower risk of osteoporosis and heparin induced thrombocytopenia
Why is protamine used for?
to reverse effects of heparin in case of a haemhorrage
What are S/E of heparin?
heparin induced thrombocytopenia and hyperkalaemia (especially in those with risk factors e.g. diabetic)
Are LMWH heparins preferred over unfractionated heparins? Why?
examples?
Yes. Used in the prevention of VTE, tx of DVT and PE.
Examples: enoxaparin and tinzaparin - used OD - long duration of action
What are OAC?
Warfarin, acenocoumarol, phenindione
How does warfarin work? Whats it used for?
Antagonises the effects of vitamin K
Used for DVT, PE, AF
How is the warfarin dose determined?
Based on patients INR
What is INR?
high INR - blood is more ‘runny’ = at risk of bleeding
low INR - blood is less ‘runny’ - lower risk of bleeding
How long does it take warfarin to work?
takes 48-72 hours for anticoagulant effect to develop
should be taken at the same time everyday so dose changes can be initiated immediately.
What would you give for immediate effect whilst waiting for warfarin to have its own effects?
Given heparin concomitantly
What are the target INR’s for which conditions?
- 5 - DVT, PE, AF
- 0 - mechanical aortic valves
- 5 - recurrent DVT, PE, mechanical mitral valve
When patient is starting on warfarin, how often is the INR measured?
daily or on alternate days but then will go on for weeks, but then 12 weeks
What is the S/E of warfarin?
what is the antidote for warfarin?
haemorrhage
Vitamin K
if a pt is undergoing elective surgery (pre-booked surgery), when should warfarin be stopped?
5 days before
Whats the half life of warfarin and the new NOAC’s?
36 hours
NOAC - half life of 12 hours
How are NOAC’s and warfarin cleared?
Warfarin - hepatic
NOACs - renal - contraindicated in patients with renal impairment
