Anticoagulation for Dentist

Question 1

Give example of anti-platelet drugs and briefly how they work (inc dose)?

Answer 1

1. Aspirin - irreversibly inhibit cyclo-oxygenase (75mg-300mg day)
2. Clopidogrel - block ADP receptor on platelet irreversibly (75mg day)
3. Prasugel - block ADP receptor irreversibly

Question 2

Why prasugrel > clopidogrel?

Answer 2

Prasugrel - more rapid and consistent

Question 3

Antiplatlets and dental tx?

Answer 3

Balance risk of bleeding vs risk thrombosis - if drugs discontinued
Don’t have to be stopped before primary care surgical procedures

Question 4

What ways can anticoagulants be administered - give examples

Answer 4

1. IV - unfractionated heparin
2. SC - low molecular weight heparin
3. Oral - warfarin, dabigatran, rivaroxaban

Question 5

What is heparin?

Answer 5

Glycosaminoglycan - derived porcine muscoa

Bind antithrombin increasing its activity - indirect thrombin inhibitor

Question 6

How to monitor heparin?

Answer 6

APTT - activated partial thromboplastin time

Kaolin cephalin

Question 7

What is low molecular weight heparin?

Answer 7

Smaller molecule made from unfractionated heparin 
Given SC
Renally excreted 
Once daily - weight adjusted dosing
No monitoring necessary

Question 8

What is the low molecular weight heparin used in Sheffield?

Answer 8

Dalteparin

Question 9

How does warfarin work?

Answer 9

Inhibit production of factor II, VII, IX, X and protein C/S

Metabolised in liver CP450

Question 10

Peak effect of warfarin and how long to wear off?

Answer 10

Usually 3-4 days - still present 4-5 days after stopping

Question 11

Monitor warfarin levels?

Answer 11

INR

Question 12

What are the anticoagulant targets?

Answer 12

INR 2.0-3.0- tx DVT/PE and AF

INR less 4: recurrent DVT/ heart valves

Question 13

Side effect warfarin

Answer 13

Bleeding, skin necrosis, embryopathy

Question 14

Reversal of heparin?

Answer 14

Protamine sulphate

Question 15

Reversal of warfarin?

Answer 15

Vitamin K
Fresh frozen plasma
Clotting factor concentrate

Question 16

Warnings pt on warfarin?

Answer 16

No IM injection, no aspirin or NSAID, no contact sport

Question 17

Example of NOACS?

Answer 17

Dibigatran - thrombin inhibitor

Rivaroxaban, edoxaban - Xa inhibitors q

Question 18

Adv NOACS

Answer 18

Standard oral dose - not weight based
Eliminate need monitor 
No alcohol or food interaction
Fewer drug interaction
BUT no antidote

Question 19

If pt taking dibigatran - how should dental XLA be managed?

Answer 19

Drug schedule 2x day

Miss morning dose and take usual time in evening

Question 20

If pt taking rivaroxavan - how should dental XLA be managed?

Answer 20

1 x dose (morn or eve)
If take morning - delay morning dose till 4 hours after haemostasis acheived
If evening - usual timing

Question 21

Other consideration NOACs in dental surgery

Answer 21

LA w/ vasoconstrictor
Infiltration or intra-ligamentary if poss
Short term anticoagulant - delay tx