anticoagulants Flashcards

1
Q

what are the benefits of warfarin?

A

can save a life from thrombo-embolism
AF patients have 60% reduction in strokes

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2
Q

what are the negatives in using anticoagulants?

A
  • Frequent to causing preventable harm and admissions to hospitals
  • Major cause of bleeding
  • Major litigation (use or not use)
  • Dose adjustments frequently required to avoid over or under anticoagulation
  • rapid fall in protein C and S in first 2-3 days - increased risk of thrombosis on this time
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3
Q

what is the mode of action of warfarin?

A

prevents vit K promoted carboxylation of glutamic acid residues of factors I, VII, IX and X
prevents vit K dependent clotting factors
full anticoagulated in 48-72hrs

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4
Q

what do protein C and S do?

A

prevent blood clotting too much

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5
Q

what is INR?

A

internalised normalised range/ ratio
- standardised to reduce variation
based on patients on variation
- way to measure patients warfarin levels

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6
Q

what is contra-indicated with warfarin?

A
  • Avoid 48hrs post partrum
  • Haemorrhagic stroke
  • Significant bleeding
  • Known coagulation defects
  • Excessive alcohol intake
  • Prone to falls
  • Endocarditis
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7
Q

which group are high risk with warfarin?

A

pregnant women, elderly, end-stage renal disease, poor drug/ clinic compliance, CVS disease

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8
Q

what needs to be measured prior to starting warfarin?

A
  • Prothrombin time – normal time for clotting
  • Activated partial thromboplastin time (APTT) – time taken to clot with specific agents added
  • Platelet count
  • FBC
  • Liver function test
  • Baseline INR – should be 1
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9
Q

how many mg within the brown warfarin pill?

A

1mg

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10
Q

how many mg within the blue warfarin pill?

A

3mg

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11
Q

how many mg within the red warfarin?

A

5mg

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12
Q

what are the indications to warfarin?

A
  • Prophylaxis of embolism in rheumatic HD +AF
  • Prophylaxis after insertion of prosthetic heart valve
  • Prophylaxis and treatment of venous thrombosis and PE
  • TIA
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13
Q

what are side effects of warfarin?

A

bleeding, hypersensitivity, skin rashes, alopecia, diarrhoea, unexplained drop in haemocrit, jaundice, hepatic dsyfunction, purple toes, skin necrosis

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14
Q

what is the warfarin antedote?

A

vitamin K - phytomeandione
- stop taking warfarin may be more beneficial?

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15
Q

how many days prior to surgery would you stop taking warfarin?

A

5 days

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16
Q

if a patient requires antocoag before surgery, what would you do?

A

bridging - using LMWH as that can be used until 2hrs prior to surgery

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17
Q

what interacts with warfarin?

A

refer to BNF
alcohol
anything that increases bleeding risk - caution
oral contraceptive
st johns wort
cranberry/ grapefruit juice
other antiplatelets - use with caution

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18
Q

what is unfractionated heparin?

A

high molecular weight molecules, highly ionised

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19
Q

how must unfractionated heparin be administered?

A

not absorbed in GI
must be IV/ SC injection - gives high monitoring

20
Q

which patients would benefit from unfractionated heparin the most?

A

high risk patients/ renal impairment - more in control and enough evidence

21
Q

what do you monitor with a patient on unfractionated heparin?

A

trust protocol
prothrombin time, activated partial thromboplastin time
platelet count - HIT
FBC, liver function test
potassium

22
Q

what is activated partial thromboplastin time?

A

time takes to clot with another agent present

23
Q

what is HIT - platelet count

A

heparin induced thrombocytopenia - contra indicated with heparin
<80 need haematology referral

24
Q

what is the antedote of unfrationated heparin?

25
what is the benefit of LMWH over warfain?
more predictable response
26
what is the action of LMWH?
indirect thrombin inhibitors - enhance antothrombin II - inhibits thrombin IIa - inactive factor Xa
27
how do you administer LMWH?
SC injection, dosage based on weight
28
what are the advantages of using LMWH over warfarin?
fixed dose, no labs, highly predictable plasma levels, higher bioavailability, ,longer half life - taken OD/ BD
29
what are the disadvantages of LMWH over warfarin?
more expensive
30
when would LMWH be best to use?
PE, DVT, thromboprophylaxis, daltaparin, tinzaparin
31
what is contra-indicated with LMWH?
all heparins, endocarditis, major trauma, epidural, avoid benzyl injections, peptic ulcer, thrombocytopenia
32
what is the antedote of LMWH?
can only be partially reversed protamine
33
what are DOACs?
direct oral anticoagulants
34
name some DOACs?
dabigatran, rivaroxaban, apixaban, edoxaban
35
when are DOACs used?
non-valvular AF, DVT, PE - treatment and prophylaxis of current VTE
36
rivaroxaban also has other uses other DOACs do not, what are they?
prophylaxis of atheromatic events following ACS with elevated cardiac biomarkers - can be taken with/ without aspirin
37
what is the action of DOACs?
prevents prothrombin to thrombin pathway acts on Xa factor
38
what are the benefits of DOACs?
no INR monitoring, predictable anticoag reponse, rapid onset (1-4hrs), lower risk of bleeding, including intracranial. stroke protection equivalent to warfarin - can go in compliance aids (dosage boxes), can be crushed
39
what is the new first line anticoagulant?
DOACs
40
what is contra -indicated with DOACs?
lesion/ condition that can increase bleeding risk significantly - current/ recent GI ulcer presence of malignant neoplasm recent brain/ spinal surgery, intercranial haemorrhage vascular aneurysms/ major intraspinal abnormalities WITH ANY OTHER ANTICOAGULANTS
41
what needs to be checked prior to starting DOACs?
check interactions age, weight renal function
42
what should rivaroxaban be taken with?
food - increases bioavailability
43
what are side effects of DOACs?
GI disturbances, pain, dsypesia, altered liver function, rash/ pruritis, epitaxis, bruising, small haemorrhages
44
what side effects are common to rivaroxaban?
dizziness, may affect ability to drive, tachycardia, dry cough
45
what does CHA2DS2-VASc do?
assess stroke risk following AF
46
what is HAS-BLED used for?
bleeding risk score system on anticoagulants
47
what is ORBIT?
bleeding risk score system for those who had AF - used more commonly in practice