Anticoagulants Flashcards
when may anticoagulation risk not outweigh the benefits?
for people at increased risk of bleeding
when do you start assessing bleeding risk in AF?
- Starting anticoagulation
- Reviewing people taking anticoagulants
what is ORBIT based on?
Based on the 5 predictors with the strongest association with major bleeding
how does the scoring system for ORBIT work?
Scores range from 0 to 7 based on the presence or absence of specific characteristics.
–There is a score of 2 points for:
*Males with haemoglobin <130 g/L or hematocrit <40%.
*Females with haemoglobin <120 g/L or hematocrit <36%.
*People with a history of bleeding (for example, gastrointestinal or intracranial bleeding, or haemorrhagic stroke).
There is a score of 1 point for people:
*Aged over 74 years.
*With estimated glomerular filtraion rate (eGFR) less than 60 mL/min/1.73m2.
*Treated with antiplatelets.
what are some of the limitations of the ORBIT tool?
Doesn’t take into account choice of anticoagulation
*ORBIT does not include all of the modifiable risk factors included in HAS-BLED
Subsequent studies found that ORBIT places more patients in the low-risk category than HAS-BLED, potentially under-predicting their major bleeding risk
*ORBIT is not the recommended bleeding risk
tool for other conditions (such as venous
thromboembolism).
*Not (yet) embedded in GP systems
what are some common risk factors for bleeding?
*Uncontrolled hypertension
*Poor control of INR in patients on vitamin K
antagonists
*Medication, including antiplatelets, SSRIs and NSAIDs
*Harmful alcohol consumption
*Reversible causes of anaemia.
what are the risks associated with treatment of warfarin/ DOAC?
DOACs are associated with a reduced risk of haemorrhagic stroke and intracerebral haemorrhage compared with warfarin
what is the difference with adherence for warfarins and DOACs?
Adherence to anticoagulation treatment is vital, but if a dose of DOACs is
missed the risks are higher due to their relatively short half life (12-24
hours). Warfarin, some benefit can be retained for 48 to 72 hours after
missing a dose
what monitoring needs to be done for warfarin/DOACS?
–DOACs have predictable pharmacokinetics, coagulation control does not
need to be monitored.
–Warfarin on the other hand needs regular blood tests to monitor INR level
how do you reverse the effect of warfarin/ doacs?
–Warfarin: vitamin k
–Dabigatran: idarucizumab*
–Apixaban and rivaroxaban: andexanet alfa*
–Edoxaban: no specific authorised reversal agent.*
how does apixaban work?
*Direct inhibitor of activated factor X (factor Xa).
what is the reversal agent of apixaban?
Reversal agent andexanet alfa
what is the dosing of apixaban?
twice daily dose
when should you reduce the dose to 2.5mg twice daily apixaban for propylyaxis of stroke and systemic embolism in non-valvular AF?
Serum-creatinine 133 micromol/litre and over is associated with age
80 years and over or body-weight 60 kg or less
–Creatinine clearance 15–29 mL/minute
how does rivaroxaban work?
*Direct inhibitor of activated factor X (factor Xa).
what is rivaroxabans reversal agent?
andexanet alfa
how do you adjust rivaroxaban in renal impairment?
–Reduce dose to 15mg CrCl 15-49mL/ min.
–Caution if CrCl 15–29 mL/minute; avoid if creatinine clearance less than
15mL/minute
what is a new licensing for rivaroxaban?
Prevention of atherothrombotic events following an acute coronary syndrome with elevated cardiac biomarkers
Low-dose rivaroxaban + aspirin alone or aspirin and clopidogrel
how does edoxaban work?
Direct and reversible inhibitor factor Xa
what is the reversal agent for edoxaban?
no specific reversal agent
when is edoxaban given?
Prophylaxis of stroke and systemic embolism in non-valvular atrial fibrillation, in patients with at least one risk factor
–congestive heart failure, hypertension, aged 75 years and over, diabetes mellitus, previous stroke or transient ischaemic attack
what weight dose adjustment is there with edoxaban?
Weight: <61kg = 30mg
what implications are there with edoxaban and renal function?
–Avoid if creatinine clearance less than 15mL/minute.
–30 mg once daily if creatinine clearance 15–50mL/minute
how does dabigatran work?
Direct thrombin inhibitor
what are the contraindications for dabigatran?
CrCl <30ml/min,
current/recent GI ulcer, elevated ALT/AST (
when should you use warfarin?
Mechanical heart valve
*Moderate to severe mitral stenosis
*Antiphospholipid antibodies
*Pregnant, breastfeeding
*INR > range of 2-3.0
*Severe renal impairment (CrCl <15mL/min)
*DOAC interactions
*Active malignancy/ chemotherapy
when you calculate a person TTRs at each visit, what do you take into account?
–exclude measurements taken during the first 6 weeks of treatment,
–calculate TTR over a maintenance period of at least 6 months.
