Wk 12: Anticoagulation

Question 1

What are the risk factors for bleeding?

Answer 1

• Uncontrolled hypertension
• Poor INR control on warfarin
• Meds: antiplatelet, SSRIs + NSAIDs
• Harmful alcohol consumption

Question 2

Give examples of differences between warfarin + DOACs

Answer 2

• DOACS: red hemorrhagic stroke + intracerebral haemorrhage
• Missed dose: DOACS = higher risk due to short HL
• Monitor: warfarin requires regular blood tests

Question 3

What reverses the effect of warfarin?

Answer 3

Vit K

Question 4

What are the MHRA alerts that you need to know about anticoagulants?

Answer 4

• DOACS: inc risk of recurrent thrombotic events in patients w/ antiphospholipid syndrome
• Rivaroxaban: 15mg + 20mg tabs taken w/ food

Question 5

What is apixaban?

Answer 5

• Direct inhibitor of activated factor X
• Reversal agent: andexanet alfa
• BD

Question 6

When should the dose of apixaban be reduced to 2.5mg BD?

Answer 6

For prophylaxis of stroke + systemic embolism in non-valvular AF:

• SCr 133um/L + >80 yrs old/body weight <60kg
• Creatinine clearance 15-29ml/min

Question 7

What is rivaroxaban?

Answer 7

• Direct inhibitor of activated factor X
• Reversal agent: andexanet alfa

Question 8

What happens to the dose of rivaroxaban if a patient has renal impairment?

Answer 8

• CrCl 15-49ml/min: red dose
• <15ml/min: avoid

Question 9

What is edoxaban?

Answer 9

• Direct + reversible inhibitor factor Xa
• No specific reversal agent
• <61kg = 30mg

Question 10

What happens to the dose of edoxaban if the patient has impaired renal function?

Answer 10

• <15ml/min: avoid
• CrCl 15-50ml/min: 30mg OD

Question 11

What is dabigatran?

Answer 11

• Direct thrombin inhibitor
• Reversal agent: idarucizumab
• CI: CrCl <30, recent GI ulcer, elevated ALT/AST

Question 12

When do you use warfarin?

Answer 12

• Mechanical heart valve
• Pregnant, breastfeeding
• Severe renal impairment <15ml/min
• Active malignancy/chemo

Question 13

What is the target INR for an acute MI, AF + venous thromboembolism?

Answer 13

• Target: 2.5
• Range: 2-3

Question 14

What is the target INR for a mechanical valve?

Answer 14

• Target: 3
• Range: 2.5-3.5

Question 15

What needs to be monitored each visit for a patient on warfarin?

Answer 15

TTR:

• Exclude measurement taken during 1st 6 wks of treatment
• Calculate TTR over maintenance period of 6 months

Question 16

What are the indicators of poor anticoagulation control?

Answer 16

• 2 INR >5 or 1 INR >8 w/in past 6 months
• 2 INR <1.5 w/in past 6 months
• TTR <65%

Question 17

What happens when rapid anticoagulation is required?

Answer 17

• Give 5mg OD for 2 days
• Measure INR on day 3
• Following dose depends on prothrombin time

Question 18

What happens when an immediate effect is required?

Answer 18

Hep or LMWH given

Question 19

What is used for people with AF?

Answer 19

• Slow loading regimen w/in 3-4 wks
• Initial: Warfarin 1mg/2mg daily
• Maintenance: warfarin 5mg daily

Question 20

What are the monitoring requirements when initiating therapy?

Answer 20

• Chen INR w/in 2-3 days
• Daily INR in hospital
• Check 1 wk after initiation steady state
• Every week during 1st month

Question 21

What are the monitoring requirements when maintaining therapy?

Answer 21

• Holding dose: recheck w/in 1-2 days
• Changing dose: recheck w/in 1-2 wks
• Stable: every 4 wks
• Unstable: 1-2 wks

Question 22

What are the adverse effects of warfarin?

Answer 22

• Haemorrhage
• Skin necrosis

Question 23

What must you do if there is a major bleed in a patient taking warfarin?

Answer 23

• Stop warfarin
• Give phytomenadione
• 5-10mg slow IV
• Prothrombin complex
• Fresh frozen plasma

Question 24

What must you do if the INR >8 in a patient taking warfarin?

Answer 24

• No bleed/minor bleed = stop warfarin
• Restart when INR <5
• If other risk factors for bleed: vit K 500mcg slow IV/5mg Po
• Repeat Vit K dose if INR too high after 24hrs