Case Study 2- Atrial fibrillation Flashcards
What is rate control in AF?
The number of heart beats per minute
60-100bpm is the normal range
What is rhythm control in AF?
The pattern in which the heart beats. Can be described as:
Regular or irregular
or
Fast or slow
What drugs can be used as rate control in AF?
Beta blockers except (sotalol)
Calcium Cannel inhibitors (diltiazem or verapamil)
Digoxin (if patient does little to no exercise
combination therapy can be used (but not verapamil)
What drugs can be used as rhythm control in AF?
Antiarrhythmics
- Beta blocker is drug treatment is needed for long term
- amiodarone
What is the mechanism of action of apixaban?
- Selective potent factor Xa inhibitor
- Also inhibits prothrombinase activity
- Indirectly inhibits platelet aggregation by thrombin
as a result:
- Decreases thrombin generation and thrombus development
- Prevents blood clot formation
- Reducing the risk of stroke and heart attacks
What counselling points would you give a patient on DOACS such as Apixaban?
- Always carry the alert card
- Do not stop taking the drug unless advice by the doctor
- Have regular reviews by a doctor
- Can crush tablet if it is too hard to swallow
What are the common side effects with DOACs?
- Risk of bleeding and bruising
- Anaemia
- Nausea and vomiting
What lifestyle advice would you give a patient on a DOAC or anticoagulation medicine?
- Exercise (maintain a healthy body weight)
- Reduce alcohol intake
- Smoking cessation
- Diet (fruits and veg and eating low saturated fats/ limiting salt intake/ high fibre)
What should you do if youve missed a dose of a DOAC such as apixiban?
- Take the next dose ASAP (if it is within 6 hours)
- If it is over 6 hours it is considered a double dose
- Do not double dose as it increases the risk of bleeding
What are the drug interaction of apixaban?
- anti-inflammatory drugs
- antidepressants
- anticoagulants
- antibiotics
- anticonvulsants
- herbal meds such as st johns ward
What baseline measurements should be taken when starting a patient on apixiban?
Baseline measurements:
- full blood count
- clotting screening including INR tests
- U&Es
- LFTS
-Serum creatinine - Orbit (risk of bleeding)
signs of bleeding and anaemia should be carefully monitored by the doctor and patient
How often should you review a generally healthy patient on apixiban
annually
How often should you review old or frail patient on apixaban ?
every6 months
How often should you review a patient with poor renal and liver if they have been prescribed apixaban
just repeat renal and liver function tests as needed, depending on what the patient usually gets
What is warfarin?
vitamin K antagonist
What is the mechanism of action of warfarin?
- it is a VKA
- Blocks the function of vit K epoxide reductase complex in the liver
- This leads to a reduction of the reduced form of vitamin K that serves as a cofactor for gamma carboxylation of vitamin K dependant coagulation factor
True or false:
INR measures the anticoagulation effect of warfarin?
true
What counselling points would you give a patient on warfarin?
- Always carry the yellow book
- keep a record of your INR levels
-dosing instructions
- dosing timings - Take the dose at the same time each day
- Expect to bruise easily
- Avoid things with high levels of vit K such as cranberry juice or grapefruit juice/ try not to significantly change your diet
- Take effective contraception
How can you refers the effects of warfarin if INR is too high?
Give the patient vitamin K which will decrease the chances of major bleeding
What is the normal range of INR of a patient taking warfarin?
Between 2-3, Ideally 2.5
What are the advantages of a DOAC compared to warfarin
- Less monitoring blood monitoring required (INR monitoring)
- DOACs are safer and more effective
- Less likely to develop a serious bleed on a DOAC/ reduced risk of bleeping
- Rapid onset
- diet does not effect INR
- Wide therapeutic window
- Fewer drug interactions than warfarin
What are the disadvantages of DOACs compared to warfarin?
- cost
- antidote is expensive
What are the advantages of warfarin compared to a DOAC?
- Cheap
- there is an antidote if INR is too high (can easily reverse its effects)
How would you switch from a DOAC to warfarin?
- Give the two medicine concurrently until the INR is >2
- Then dose the vit K antagonist as normal
- Continue to test the INR making sure that it is in range (between 2-3 but ideally 2.5)
How would you switch patient from warfarin to a DOAC?
- Start doac if INR is less than 2
- Start DOAC next day if INR is between 2-2.5
- If INR is greater than 2.5 WAIT till INR is less than 2 to start DOAC
