Case Study 2- Atrial fibrillation

Question 1

What is rate control in AF?

Answer 1

The number of heart beats per minute

60-100bpm is the normal range

Question 2

What is rhythm control in AF?

Answer 2

The pattern in which the heart beats. Can be described as:

Regular or irregular

or

Fast or slow

Question 3

What drugs can be used as rate control in AF?

Answer 3

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)

Question 4

What drugs can be used as rhythm control in AF?

Answer 4

Antiarrhythmics

• Beta blocker is drug treatment is needed for long term
• amiodarone

Question 5

What is the mechanism of action of apixaban?

Answer 5

• 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

Question 6

What counselling points would you give a patient on DOACS such as Apixaban?

Answer 6

• 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

Question 7

What are the common side effects with DOACs?

Answer 7

• Risk of bleeding and bruising
• Anaemia
• Nausea and vomiting

Question 8

What lifestyle advice would you give a patient on a DOAC or anticoagulation medicine?

Answer 8

• 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)

Question 9

What should you do if youve missed a dose of a DOAC such as apixiban?

Answer 9

• 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

Question 10

What are the drug interaction of apixaban?

Answer 10

• anti-inflammatory drugs
• antidepressants
• anticoagulants
• antibiotics
• anticonvulsants
• herbal meds such as st johns ward

Question 11

What baseline measurements should be taken when starting a patient on apixiban?

Answer 11

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

Question 12

How often should you review a generally healthy patient on apixiban

Answer 12

annually

Question 13

How often should you review old or frail patient on apixaban ?

Answer 13

every6 months

Question 14

How often should you review a patient with poor renal and liver if they have been prescribed apixaban

Answer 14

just repeat renal and liver function tests as needed, depending on what the patient usually gets

Question 15

What is warfarin?

Answer 15

vitamin K antagonist

Question 16

What is the mechanism of action of warfarin?

Answer 16

• 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

Question 17

True or false:

INR measures the anticoagulation effect of warfarin?

Answer 17

true

Question 18

What counselling points would you give a patient on warfarin?

Answer 18

1. Always carry the yellow book
   - keep a record of your INR levels
   -dosing instructions
   - dosing timings
2. Take the dose at the same time each day
3. Expect to bruise easily
4. Avoid things with high levels of vit K such as cranberry juice or grapefruit juice/ try not to significantly change your diet
5. Take effective contraception

Question 19

How can you refers the effects of warfarin if INR is too high?

Answer 19

Give the patient vitamin K which will decrease the chances of major bleeding

Question 20

What is the normal range of INR of a patient taking warfarin?

Answer 20

Between 2-3, Ideally 2.5

Question 21

What are the advantages of a DOAC compared to warfarin

Answer 21

• 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

Question 22

What are the disadvantages of DOACs compared to warfarin?

Answer 22

• cost
• antidote is expensive

Question 23

What are the advantages of warfarin compared to a DOAC?

Answer 23

• Cheap
• there is an antidote if INR is too high (can easily reverse its effects)

Question 24

How would you switch from a DOAC to warfarin?

Answer 24

1. Give the two medicine concurrently until the INR is >2
2. Then dose the vit K antagonist as normal
3. Continue to test the INR making sure that it is in range (between 2-3 but ideally 2.5)

Question 25

How would you switch patient from warfarin to a DOAC?

Answer 25

• 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