INR / warfarin chart

Question 1

What does INR stand for?

Answer 1

international normalised ratio

Question 2

Normal INR value?

Answer 2

1

Question 3

INR range for those on warfarin?

Answer 3

2-3 (ideally 2.5)

Question 4

What could it mean if someone not on warfarin has a raised INR?

Answer 4

Underlying medical condition

Question 5

What does INR measure?

Answer 5

the tendency of a person’s blood to clot

Question 6

What does a high INR indicate?

Answer 6

The blood takes longer to clot so there is an increased bleeding risk

Question 7

What does a low INR indicate?

Answer 7

The blood is thicker and so clots in a lower time leading to an increased clotting risk.

Question 8

What is warfarin?

Answer 8

It is a vitamin K antagonist

Question 9

MoA of warfarin?

Answer 9

It works by blocking an enzymes called vitamin K epoxide reductase
this leads to a decrease in clotting factors 2,7,9 and 10 (1972)

Question 10

Why do we Rx warfarin?

Answer 10

To treat blood clots / to prevent them
examples -> DVT PE and stroke prevention in AF

Question 11

What counselling is given to those starting warfarin?

Answer 11

They need regular blood tests
to take the warfarin at the same time everyday
DO NOT DOUBLE DOSE

Question 12

What focused questions in terms of medications?

Answer 12

Current medications (other Rx, OTC, herbal)
Why on warfarin?
What dose?
How long on warfarin?
Any side effects?
Adherence to meds
How and when
Any missed doses?
Any double doses?

Question 13

What medications may interact with warfarin?

Answer 13

Aspirin
NSAIDs
St johns wort
OCP /HRT

Question 14

What are some high INR symptoms?

Answer 14

Headache
Severe stomach ache
Increase bruising
Prolonged bleeding after minor cuts / menstrual bleeding / gum bleeding.
blood in urine
blood in stool (diarrhoea - melaena - tarry stool)
Blood in vomit (haematemesis

Question 15

What are some low INR symptoms?

Answer 15

STROKE SX
- sudden weakness /
numbness/ tingling in
any limb
- Visual changes
- Inability to speak
DVT / PE SX:
- new pain
- swelling
- redness
- heat in body parts
- new SOB
- chest pain

Question 16

Relevant PMH?

Answer 16

Liver failure - lack of clotting factors
Bleeding disorders - haemophilia, factor 7 deficiency etc

Question 17

Focused Shx questions to ask

Answer 17

Diet
- any changes?
increase or decrease in vit K consumption
Alcohol intake
- binge drinking?
Smoking?

Question 18

What foods contain vitamin K?

Answer 18

green fruit / veg
Eg - broccoli, spinach, kale, celery, cucumber, green beans, green apples / grapes, pears and avocado etc

Question 19

What might a change in vitamin K intake lead to?

Answer 19

A change in the vitamin K levels in the blood and so a change in the 1972 clotting factors levels
so it is important to keep this dietary level consistent

Question 20

What is the effect on alcohol and smoking on INR?

Answer 20

Can cause INR increase

Question 21

What advice can given to reduce bleeding risk?

Answer 21

Avoid activities that can cause bruising / bleeding
Shave gently
tell any other HCP (eg dentist) that they take anticoagulants.

Question 22

How to tx elevated INR

Answer 22

Vitamin K
Blood components given via transfusion to stop any bleeding
W/ no clear explanation a reduction in warfarin dose and rechecking of INR can happen

Question 23

How to tx low INR

Answer 23

LMWH, warfarin
compression stockings if immobile