CVS - Blood Clot/ Anticoagulants

Question 1

Which is more problematic if a dose is missed - DOAC or Warfarin? and why?

Answer 1

DOAC
because it has a shorter half life, which means there will be have greater loss of anticoagulation than warfarin.

Question 2

What to do if you miss a WARFARIN dose

Answer 2

Take the missed dose as soon as you remember. If you do not remember until the next day, skip the missed dose and take your next dose at the usual time.

Question 3

What to do if you miss DABIGATRAN dose

Answer 3

Take dose as soon as you remember
If a dose is more than 6 hours late, the missed dose should NOT be taken and the next dose should be taken at the normal time.

Question 4

What to do if you miss a RIVAROXABAN dose

Answer 4

Take next dose as soon as you remember if you dont remeber til the next day skip dose

** if its treating DVT or PE: 15mg BD…
Do not take more than two 15mg tabs in a single day

(but can take 2x15mg at the same time to make a total of 30mg on one day e.g. if you miss morning dose and remember evening dose take two).

Continue with 15mg twice daily the following day

Question 5

What to do if missed APIXABAN dose

Answer 5

Take the missed dose as soon as you remember.

If you do not remember until
- the next day
- MORE THAN 12 HRS (Once Daily Dose)
- or MORE THAN 6HRS (Twice Daily dose),

Skip the missed dose and take your next dose at the usual time.

Question 6

What to do if missed EDOXABAN dose

Answer 6

Take the missed dose as soon as you remember.

If you do not remember until
- the next day
- MORE THAN 12 HRS,

Skip the missed dose and take your next dose at the usual time.

Question 7

What is are the DOACs onset of action timing

Answer 7

1 - 4 hrs

Dabigatran 0.5-2hrs

Edoxaban 1-2hrs

Apixaban &
Rivaroxaban 2-4hrs

**roughly

Question 8

What if WARFARIN onset of action

Answer 8

3-5 days

Question 9

What is Heparin Induced Thrombocytopenia?
How long does it take to occur?
Which Heparin is more likely to cause it?
How to manage it?

Answer 9

Developing a low platelet count (reduction of at least 30%)
Can occur 5-10 days after commencing Heparin
Unfractionated Heparin more likely to cause it
Use of Haparinoid e.g. Danaparoids

Question 10

Which DOAC causes the most GI side effects

Answer 10

Rivaroxaban
- GI Discomfort
- Constipation
- Diarrhoea
- Nausea
- Vomiting

Question 11

What BASE LINE test need to be done before commencing DOACs (5)

Answer 11

FBC
Renal (adjust dose accordingly)
LFT
*Prothrombin Time (PT)
* Activated partial Thromboplastin Time (APTT).

Question 12

Which DOAC is least likely to be chosen in renal impairment?

Answer 12

Dabigatran
Caution starts from CrCl being or less than 30

Question 13

What is the antidote for too much warfarin (INR to high)

Answer 13

phytomenadione (vitamin K1)

Question 14

What is the antidote of Dabigatran

Answer 14

IDARUCIZUMAB

Question 15

What is the antidote for Apixaban and Rivaroxaban

Answer 15

ANDEXANET ALFA

Question 16

What Heparin should be used in renal failure

Answer 16

Unfractionated Heparin
(still may require a dose reduction)

Question 17

What VTE treatment is used in pregnancy?
and Why (3)

Answer 17

LMWH - Low Molecular Weight Heparin
because…
- It doesn’t cross the placenta
- Lower risk of HIT
- Lower risk of Osteoperosis

(BNF does state it is an unlicensed & the manufacturer suggest avoiding it due to vials containing Benzyl Alcohol)

Question 18

What LMWH is suitable in breast feeding

Answer 18

Enoxaparin

Question 19

What do you monitor when using Heparins (5)

Answer 19

Weight - dose depends on it
Platelets - risk of HIT
Potassium - risk of hyperkalemia
Renal - especially with LMWH
LFT

Question 20

What is the antidote for Heparins

Answer 20

Protamine Sulphate
Fully reverses - UNFRACTIONATED
Partially reverses - LMWH

Question 21

Which DOAC has a Loading and Maintenance dose

Answer 21

Apixaban

Question 22

Which DOACs has Twice Daily dosing for DVT and PE prophylaxis?
&
Which DOACs has ONCE daily dosing for DVT and PE prophylaxis?

Answer 22

Twice Daily = Apixaban (5mg BD) and Dabigatran (150mg BD)

Once Daily = Rivaroxaban (20mg OD) and Edoxaban (30-60mg OD)

Question 23

Which DOACs has Twice Daily dosing for DVT and PE treatment?
AND
Which DOACs has ONCE daily dosing for DVT and PE treatment?

Answer 23

Twice daily = Apixaban (10mg BD) and Rivaroxaban (15mg BD 21/7 then 20mg OD) and Dabigatran (75, 110-150 BD dependent on age,
Once daily = edoxaban (30/60mg OD dependent on weight)

Question 24

Which DOAC must be taken with food

Answer 24

Rivaroxaban - to increase absorption

Question 25

Which DOAC must remain in its original container

Answer 25

Dabigatran

Question 26

Which DOAC interacts with Verampamil as well as Amiodarone

Answer 26

Dabigatran
- Dose reduction required 110mg BD

Question 27

An INR within ____ units of the target is satisfactory?

Answer 27

0.5

Question 28

A target INR of ____ is used for most things e.g. DVT, PE, AF, cardioversion

When is it a target of ___?

Answer 28

2.5

3.5 = recurrent DVT/PE in pt already receiving anticoagulant or if mechanical heart valve

Question 29

Which DOAC need warning label
“Swallow whole, do not crush or chew”

Answer 29

Dabigatran
(opening capsule increses risk of bleeding)

Question 30

When should warfarin be avoided in pregnancy

Answer 30

1st and 3rd trimester
(If unavoidable babies of mother taking warfarin at time of delivery should be offered immediate prophylaxis with IM phytomenadione (vitamin K1).)

Question 31

Is warfarin safe in breast feeding

Answer 31

YES

Question 32

treatment for suspected DVT/PE
1st and 2nd line

Answer 32

1st Line → Apixaban or Rivaroxaban
2nd Line → LMW.Heparin e.g. Dalteparin, Enoxaparin, Tinzaparin for 5 days FOLLOWED BY Dabigatran or Edoxaban
OR
LMW.Heparin e.g. Dalteparin, Enoxaparin, Tinzaparin for 5 days or until INR at 2 or more for 24hrs FOLLOWED BY Warfarin (Vit K Antagonist)

Question 33

A warfarin pt is about to have surgery, how many days before should they stop taking their medicine

Answer 33

5 days