WARFARIN
MANAGEMENT
GUIDELINES
WARFARIN
WISE
FEBRUARY 2006
LIVERPOOL HOSPITAL
DEVELOPED AS PART OF THE “SAFER SYSTEMS SAVING LIVES “ PROJECT.
WARFARIN MANAGEMENT IN ACUTE STROKE PATIENTS
TABLE OF CONTENTS
ANTI-COAGULATION USING WARFARIN ........................................................ 1
OUTCOME ................................................................................................................ 1
GUIDELINES ............................................................................................................. 1
1.
2.
3.
4.
5.
6.
PRESCRIBING AND ADMINISTRATION ......................................................................... 1
MONITORING ........................................................................................................... 2
DRUG INTERACTIONS .............................................................................................. 2
INR GREATER THAN THERAPEUTIC RANGE ............................................................... 3
DISCHARGE INSTRUCTIONS ...................................................................................... 3
RENAL IMPAIRMENT ................................................................................................. 4
COMPILED BY ........................................................................................................... 5
PATIENT EDUCATION & DISCHARGE MANAGEMENT ....................................... 6
WARFARIN THERAPY CHART ....................................................................... 7
DISCHARGE CHECKLIST .............................................................................. 8
WARFARIN ALERT CARD SAMPLE ............................................................................... 8
WARFARIN: IMPORTANT INFORMATION FOR PATIENTS .................................... 9
WARFARIN ALERT CARD ............................................................................................ 9
INR BLOOD TESTS.................................................................................................... 9
WARFARIN ............................................................................................................... 9
WARFARIN DOSE ...................................................................................................... 9
ADMINISTRATION TIME............................................................................................... 9
LABORATORY TESTS ................................................................................................. 9
OTHER MEDICATIONS .............................................................................................. 10
DIETARY PRINCIPLES .............................................................................................. 10
SURGICAL PROCEDURES ......................................................................................... 10
TRAVEL .................................................................................................................. 10
PREGNANCY ........................................................................................................... 10
SIGNS OF BLEEDING ................................................................................................ 10
D:\106741972.doc
Table of Contents
ANTI-COAGULATION USING WARFARIN
OUTCOME
To promote therapeutic anti-coagulant levels the following guidelines should be implemented
to minimise the risk of bleeding and thromboembolism.
GUIDELINES
COUMADIN® is the preferred brand of Warfarin at Liverpool Health Service. Coumadin will
be supplied for all inpatients starting Warfarin. Patients already on the Marevan® brand
should use their own tablets, as Marevan and Coumadin are NOT EQUIVALENT.
Reference: Aust Prescriber Vol 21 No. 3 1998.
1.

PRESCRIBING AND ADMINISTRATION
The prescribing doctor will write the indication for Warfarin, the duration of Warfarin therapy
and the desired therapeutic INR range on the ‘Warfarin Therapy Chart’ (Page 7).

For chronic AF and valve replacements, start Warfarin alone.

For restarting Warfarin postoperatively, restart patient on ‘usual’ pre-operative
maintenance dose - do not reload.

For acute DVT or PE, start Warfarin on the same day as Heparin/Low Molecular Weight
Heparin (LMWH) (see Table 4). It is generally recommended to overlap Heparin/LMWH
with Warfarin for a minimum of five (5) days and until the INR is >2.0 for at least two (2)
consecutive days.

Assess each patient for risk factors for increased sensitivity to warfarin and therefore
bleeding:
Risk factors include:
> 'frail' elderly;
> low body weight;
> abnormal liver function tests including albumin;
> INR  1.4;
> any other bleeding risk such as severe heart failure or low platelets; and
> concomitant drugs which increase the effect of Warfarin (see Table 2).

If no risk factors exist, start Warfarin at 5mg daily, monitor INR daily and adjust dose
using the nomogram in Table 1.

If risk factors exist, consider smaller loading doses (2 - 4mg) and seek senior/specialist
advice. Monitor INR daily.

High loading doses such as 10 mg should not be used as they may increase the risk of
bleeding.

Warfarin is to be administered at 1800 hours and must be prescribed before that time.

Aged adjusted commencing dose:
> 60 to 70 years - 4.5mg/day
> 70 to 80 years - 4.0mg/day
> 80 to 90 years - 3.5mg/day
(Source: Sullivan Nicholaides Pathology)
Liverpool Stroke Unit Warfarin Management guidelines adapted from the Alfred Hospital Melbourne,
Yarrawonga Health Service and Armidale Health Service, WA by the” Safer Systems Saving Lives”
project. Warfarin management in acute stroke patients. February 2006
Page 1 of 10
(If Pre-Treatment INR, Hepatic Function and
Serum Albumin are Normal)
Day
INR
Dose
<1.4
5 mg
1
TABLE 1
Dosage Adjustment in a Patient Starting
Warfarin
2
Ensure the Patient is Entering Warfarin Dose
and INR in the Warfarin Booklet and has
Acknowledged Education (See Page 6)
3
Based on Gedge et al a Comparison of a Low
Dose Warfarin Induction Regimen with the
Modified Fennerty Regimen in Elderly Patients
[Age Ageing 2000; 29:31-4]
<1.8
1.8 to 2.0
>2.0
<2.0
2.0 to2.5
2.6 to2.9
3.0 to3.2
3.3 to3.5
>3.5
<1.4
1.4 to 1.5
1.6 to 1.7
1.8 to 1.9
2.0 to 2.3
2.4 to 3.0
3.1 to 3.2
3.3 to 3.5
>3.5
4
5 mg
1 mg
Nil
5 mg
4 mg
3 mg
2 mg
1 mg
Nil
10 mg
7 mg
6 mg
5 mg
4 mg
3 mg
2 mg
1 mg
Nil
Dosage Adjustment After Day 4 Depends on
Clinical Judgement
2.

MONITORING
Daily INR monitoring and warfarin dose adjustment is necessary until the INR is therapeutic
and stable.

Blood should be collected for INR on the morning blood collection round. (Write Request
Form previous day.)
3.

DRUG INTERACTIONS
Certain drugs may increase or decrease the effect of Warfarin and the risk of bleeding/
thrombosis (Table 2).

When starting or stopping a drug, particularly antibiotics, the INR must be checked 1 to 2
days after the change in therapy.
SOME MAJOR DRUG INTERACTIONS WITH WARFARIN
TABLE 2
INCREASED
DECREASED
Effect of Warfarin
Anti-Platelet Agents
Analgesics
Abciximab (ReoPro), Aspirin,
Paracetamol (Large
Dipyridamole, NSAIDs,
Doses ie. 4 to 7g Per
Clopidogrel, Tirofiban
Week), Tramadol
COX-2 Inhibitors
Anticonvulsants
Celecoxib, Rofecoxib
Phenytoin
Check with
Pharmacy or
Via Clinicians
Health
Channel
(Micromedex)
if More
Information
Required
Antibiotics
Cephalosporins, Macrolides,
Metronidazole, Sulphonamides,
Quinolones, Vancomycin
Antifungals
Itraconazole, Fluconazole,
Ketoconazole
Antiarrythmics
Amiodarone, Mexiletine,
Verapamil
Herbal Medicines
Dong Quai, Garlic, Papaya, St
Johns Wort, Ginkgo, Ginger and
Garlic (Large Amounts), Guarana
Selective Serotonin
Reuptake Inhibitors
Fluoxetine
Effect of Warfarin
Ascorbic Acid
(Large Doses)
Vitamin K
Anticonvulsants
Carbamazepine,
Phenytoin
Antibiotics
Rifampicin, Rifabutin
Tricyclic
Antidepressants
Sedatives
Barbiturates
Raloxifene,
Tamoxifen
Quinine and
Quinidine
Herbal Medicines
Ginseng, Slippery Elm
Bark, Green Tea,
Co-Enzyme Q10
Liverpool Stroke Unit Warfarin Management guidelines adapted from the Alfred Hospital Melbourne,
Yarrawonga Health Service and Armidale Health Service, WA by the” Safer Systems Saving Lives”
project. Warfarin management in acute stroke patients. February 2006
Page 2 of 10
4.

INR GREATER THAN THERAPEUTIC RANGE
If INR is greater than the therapeutic range, see Table 3 for management.

Contact prescribing doctor if INR > 6 and / or there is any bleeding during Warfarin therapy.
TABLE 3 :
BLEEDING
NO
YES
INR < 5
INR >5 TO <9
INR >9
Withhold Warfarin
Check INR
at 24 Hours
(No Vitamin K)
Resume Warfarin at
Lower Dose when
INR is In
Therapeutic Range
Withhold Warfarin
Give
2mg Vitamin K
(Oral)
Withhold Warfarin
and Give
5mgVitamin
(IV)
OR
IF Rapid Reversal
Necessary
Give
4mg Vitamin K
(Oral)
Check INR
at 6 Hours
If Rapid
Reversal Necessary
(ie. Surgery)
Give
2mg Vitamin K
(Oral)
Check INR
at 24 Hours
If INR >4
Give
2mg Vitamin K
(Oral)
Resume Warfarin
at Lower Dose
When In
Therapeutic Range
INR >15
OR
Life Threatening
Bleeding or
Warfarin Overdose
Give
10mg Vitamin K (IV)
Supplement with
FFP
If INR >4
Check INR
at 6 Hours
Give
5mg Vitamin K
(IV)
If INR >4
Recheck at 6 Hours
Then Daily for Three
(3) Days
(If INR Rises
LMO to Assess)
Resume Warfarin
at Lower Dose
When In
Therapeutic Range
Give
10mg Vitamin K
(IV)
Recheck INR at
6 Hours Then Daily
for Three (3) Days
If INR >4
LMO to Assess Repeat Vitamin K
as Necessary

Oral Vitamin K tablets should not be used as only 10mg tablets are available. Use the IV
injection (Konakion MM) solution orally.

For oral administration give undiluted.

For some conditions such as prosthetic heart valves, the degree of reversal must be decided
on an individual basis.
All patients with bleeding should be evaluated to identify local
anatomical reasons for bleeding. It may be advisable to consult HMO.
NOTE:
Clinical judgement to be used when assessing a patient’s severity to bleeding. Heparin to be
initiated when Vitamin K has been administered in excessive doses making the patient
unresponsive to Warfarin therapy. Heparin to be continued until Warfarin becomes therapeutic.
Notes on Vitamin K Administration:

Use of Vitamin K may be followed by a period of Warfarin resistance. If after cessation of
bleeding, anti-coagulation is once again necessary, eg. in patients with mechanical heart
valves, Heparin may be required until INR levels are once again therapeutic.

Do not mix ampoules of Vitamin K with other infusion solutions.
5.

DISCHARGE INSTRUCTIONS
Discharging Medical Officer is responsible for Discharge Summary. Information to include:
>
>
>
>
target INR;
Warfarin dose;
date of next test; and
proposed duration of treatment.
Include this information in the Discharge Summary.
Liverpool Stroke Unit Warfarin Management guidelines adapted from the Alfred Hospital Melbourne,
Yarrawonga Health Service and Armidale Health Service, WA by the” Safer Systems Saving Lives”
project. Warfarin management in acute stroke patients. February 2006
Page 3 of 10

The ‘Warfarin Therapy Chart’ should be given to the patient and a copy to the patient’s GP,
and the discharge checklist on the back of this chart should be completed and signed.

The ‘Discharge Instructions’ should be completed by a medical officer and given to the
patient.

The ‘Patient Education and Discharge Management’ should be completed and
counselling provided by the clinical pharmacist or appropriate Registered Nurse. A ‘Warfarin
Alert Card’ and ‘Important Information for Patients’ should be given to the patient.
TABLE 4
SUGGESTED TREATMENT TIMETABLE
Timeline
Management Plan
Pre
Treatment
Commencing
Day 1
Day 2
Day 3
Day 4
Day 5
Day 6
Day 7
Post First
Week
Full Blood Count (FBC)
International Normalised Ratio (INR)
Activated Partial Thromboplastin Time (APTT)
Biochemistry
Liver Function Test
Oral Warfarin as Per Age Adjusted Nomogram
S/C Enoxaparin (Clexane) 1mg/kg bd
Oral Warfarin as Per Age Adjusted Nomogram
S/C Enoxaparin (Clexane) 1mg/kg bd
Full Blood Count (FBC)
International Normalised Ratio (INR)
Oral Warfarin as Per Nomogram
S/C Enoxaparin (Clexane) 1mg/kg bd
Full Blood Count (FBC) - If Indicated
International Normalised Ratio (INR)
Oral Warfarin as Per Nomogram
S/C Enoxaparin (Clexane) 1mg/kg bd
Full Blood Count (FBC) - If Indicated
International Normalised Ratio (INR) - If Indicated
Oral Warfarin as Per Nomogram
S/C Enoxaparin (Clexane) 1mg/kg bd
Full Blood Count (FBC) - Note Platelets
International Normalised Ratio (INR) - If Indicated
Cease S/C Enoxaparin (Clexane) 1mg/kg bd if INR is Therapeutic for the Previous 48
Hours (INR Range 2-3)
If INR Not Therapeutic Range Administer S/C Enoxaparin (Clexane) 1.5mg/kg
Full Blood Count (FBC) - If Indicated
International Normalised Ratio (INR)
Cease S/C Enoxaparin (Clexane) 1mg/kg bd if INR is Therapeutic for the Previous 48
Hours (INR Range 2-3)
Continue Warfarinisation for at Least 3 Months
Check International Normalised Ratio (INR) Weekly as Appropriate
GP / MO May Wish to Discuss Future Management and Duration of Treatment with a
Specialist Physician
6. RENAL IMPAIRMENT
The following dosage adjustments are recommended for the treatment dosage ranges. This
dosing applies to patients with a creatinine clearance of less than 30mL/min.
Drug
Normal Dosing
Enoxaparin
Enoxaparin
1 mg/kg Twice Daily
1.5 mg/kg Once Daily
Severe Renal Impairment
Creatinine Clearance Less Than
30mL/min
1 mg/kg Once Daily
1 mg/kg Once Daily
Although no dosage adjustment is recommended in patients with moderate (creatinine
clearance 30-50mL/min) and mild (creatinine clearance 50-80mL/min) renal impairment,
careful clinical monitoring of potential bleeding complications is advised.
Liverpool Stroke Unit Warfarin Management guidelines adapted from the Alfred Hospital Melbourne,
Yarrawonga Health Service and Armidale Health Service, WA by the” Safer Systems Saving Lives”
project. Warfarin management in acute stroke patients. February 2006
Page 4 of 10
COMPILED BY

Safer Systems Saving Lives Collaboration. Liverpool Hospital. Warfarin in acute stroke
patients program (WASPP) working party. April 2006

Pharmacy Department in consultation with the Medical Services and the Pharmacy
Advisory Committee.

Armadale Health Service.
With reference and acknowledgements to:

The Western Hospital Anti-coagulation and Thromboembolism Prophylaxis (Guidelines
for), 1999.

North Western Health, Prescriber Guidelines for Initiation of Full Anti-coagulation, 1999.

The Alfred, Guidelines on the Use of Anticoagulants. 1998.

Adapted from Wimmera Warfarin Therapy Chart in: Wimmera Clinical Risk Management
- A Systematic Approach To Reducing Medical Errors. Wimmera Health Care Group,
2001.
Liverpool Stroke Unit Warfarin Management guidelines adapted from the Alfred Hospital Melbourne,
Yarrawonga Health Service and Armidale Health Service, WA by the” Safer Systems Saving Lives”
project. Warfarin management in acute stroke patients. February 2006
Page 5 of 10
LIVERPOOL HOSPITAL
HEALTH SERVICE
PATIENT EDUCATION &
DISCHARGE MANAGEMENT
Date: ……………………………………..
PATIENT IDENTIFICATION
UNIT RECORD NO: …………………………………………………….…………….
SURNAME: …………………………………………………………………………….
GIVEN NAMES:………………………………………………………….…………….
DATE of BIRTH: ………….../………....../…………...
Sex ……….……………..
(Or Affix Patient Label)
Education to begin at commencement of Warfarin Therapy including ongoing completion of the booklet
patient. Only check patient’s knowledge twice if patient answered ‘no’ to any question in first session.
OBJECTIVES OF EDUCATION : Prior to Discharge the Patient Will be Able to:
1. Indicate that He/She has a Warfarin Education Booklet/ information sheet
Yes
2. State that He/She has Read the Booklet/information sheet
Yes
3. Demonstrate that the Documentation of the Dose and INR in the Warfarin
Yes
Booklet/information sheet is up to Date
4. Explain the Action of Warfarin
 Anticoagulant drug, used to prevent or treat thrombosis by decreasing the clotting power of the
Yes
blood.
5. Answer the Following Questions Regarding Warfarin
 Are you aware there are two brands of Warfarin? (Yes)
Yes
 State the brand that you are on (Marevan / Coumadin).
Yes
 Are the two brands the same? (No)
Yes
 Can you swap between brands? (No)
Yes
6. State: (a) Why He/She is Taking Warfarin
(b) The Length of Time Required to Take Warfarin
 To prevent clot formation around the prosthetic or bioprosthetic valve.
Yes
 To prevent the recurrence of deep vein thrombosis (DVT).
Yes
 To prevent clot formation in heart (Atrial Fibrillation).
Yes
 Length of time (see “planned duration” on Page 3).
Yes
7. Identify the 3 manufactured doses of Warfarin brand he/she is taking:
 Coumadin 1 mg - Light Tan; 2 mg - Lavender; 5 mg - Green
Yes
8. State: (a) When to take Warfarin
 With the evening meal every day - use a calendar.
Yes
(b) Why it is Important to Take the Drug at the Same Time Every Day
 To maintain consistency for checking of INR.
Yes
9. Outline the Steps to Take if They Forget to Take their Dose of Warfarin at 6.00pm
 If patient remembers within two to three hours they can take Warfarin.
Yes
 If longer don’t take Warfarin, take next dose when it is due and tell your doctor or laboratory.
Yes
10. Outline When Blood Tests are Required at Home
 Every 2nd day until INR is stabilised, then as directed by the GP or Pathology Service.
Yes
11. Identify Significant Signs of Bleeding
 Obvious bleeding ie. cuts, nosebleed, bleeding gums.
Yes
 Less obvious bleeding – urine, faeces, vomit and coughing.
Yes
12. State What He/She Will do in the Event of Signs of Bleeding
 Call the GP promptly.
Yes
13. Identify other Medications that May Interfere with the Way that Warfarin Works
 Prescription medications and over the counter medications eg. aspirin, paracetamol or other pain
Yes
medications, rubs, liniments, cold or cough preparations.
 Antacids, laxatives, multi-vitamins (may contain Vitamin K).
Yes
 Herbal medications.
Yes
14. Identify Illnesses that Require Reporting to Their GP
 Diarrhoea, vomiting.
Yes
 Infection or fever.
Yes
 Pain, swelling or discomfort.
Yes
15. Understand Significant Dietary Facts
 Maintain a well balanced and consistent diet – Avoid crash dieting and binge eating.
Yes
 Stabilise intake of Vitamin K. This includes green leafy vegetables.
Yes
 If taking vitamin or herbal supplements discuss with GP or pharmacist.
Yes
 Take alcohol in moderation.
Yes
16. Understands the Discharge Instructions Sheet Completed by the Doctor
Yes
17. Patient has had Warfarin Education with Pharmacist/RN
Yes
Pharmacist's Signature:
Date:
Staff Members Signature:
Designation:
SEND COMPLETED FORM TO PHARMACY
by the
No
No
No
No
No
No
No
No
No
No
No
No
No
No
No
No
No
No
No
No
No
No
No
No
No
No
No
No
No
No
No
No
No
Issued: July 2004
Page 6 of 10
LIVERPOOL HOSPITAL
HEALTH SERVICE
PATIENT IDENTIFICATION
UNIT RECORD NO:
WARFARIN THERAPY CHART
SURNAME:
Name of GP: …………………………………………………….
Date: ………./………./……….
…………………………………………………….…………
…………………………………………………………………………
GIVEN NAMES:
………………………………………………………….…………
DATE of BIRTH:
………….../…………...../…………...
Faxed: ………./………./……….. Faxed By: ……………….
Sex ……….…………
(Or Affix Patient Label)
INDICATION:
Atrial Fibrillation
Deep Vein Thrombosis
Pulmonary Embolism
Prosthetic Valve
Other: ……………………………………………………………………………………………………………………………
PRESCRIBER'S SIGNATURE:
SURNAME (Print):
SUGGESTED THERAPEUTIC INR RANGES (TARGET INR)
Low Risk Mechanical Prosthetic Heart Valves
High Risk Mechanical Prosthetic Heart Valves
All other indications
Date
This data should be
Commenced
included in the Discharge
Summary and the Warfarin
Booklet
Target INR
2.0 to 3.0
2.5 to 3.5
2.0 to 3.0
Planned
Usual Maintenance
Duration
Dose
INSTRUCTIONS FOR USE:
1. This WARFARIN THERAPY CHART must be used for EVERY patient on oral Anticoagulant Therapy.
2. The doctor should write in the Regular Medications section of the Medication Chart “SEE WARFARIN THERAPY
CHART” or should apply the Warfarin sticker provided. If this is not done, then a nurse or pharmacist should do
it.
3. YDHS ‘Guidelines for Anti-Coagulation Using Warfarin’ should be used when prescribing warfarin, which are
available on all wards.
4. If patient's Marevan is unavailable, only Coumadin is kept at YDHS, so use Patient's own.
TREATMENT ORDERS / TELEPHONE ORDERS / RECORD OF TREATMENT
INR
WARFARIN
(Coumadin)
Dosage
Time to
be
Given
mg
1800
WARFARIN
mg
1800
WARFARIN
mg
1800
WARFARIN
mg
1800
WARFARIN
mg
1800
WARFARIN
mg
1800
WARFARIN
mg
1800
WARFARIN
mg
1800
WARFARIN
mg
1800
WARFARIN
mg
1800
WARFARIN
mg
1800
WARFARIN
mg
1800
WARFARIN
mg
1800
WARFARIN
mg
1800
WARFARIN
mg
1800
Date
Time
Initial
Doctor's Signature
MR/168
WARFARIN
Administered
Nurse's Signature
NEXT INR DUE AM ON: ……………………………………………………………………….. (Day and Date)
COPY TO BE GIVEN TO PATIENT ON DISCHARGE
D:\106741972.doc
WARFARIN THERAPY CHART
Date
Page 7 of 10
DISCHARGE CHECKLIST
The following checklist must be completed and signed prior to the patient being discharged
from Yarrawonga District Health Service. The relevant documentation is available in the
'Medication Procedures Manual' or in the 'Clinical Procedures Manual'.
Sign When
Completed
1.
The ‘Discharge Instructions’ should be completed and given to the
patient.
2.
The ‘Patient Education and Discharge Management’ should be
completed, with counselling provided or organised with the clinical
pharmacist or Nurse.
3.
The ‘Warfarin: Important Information for Patients’ and a blue ‘Warfarin:
Important Instructions for Patients’ book should be given to the patient.
4.
A ‘Warfarin Alert Card’ should be produced and given to the patient.
WARFARIN ALERT CARD SAMPLE
A personalised plastic ‘Warfarin Alert Card’ should be organised for the patient through the
ward pharmacist prior to discharge. If the patient is being discharged over the weekend, the
card can be sent to them. The following is a sample of what the card will look like:
WARFARIN PATIENT
DETAILS
Name: ……………………………………..
IMPORTANT PATIENT
INFORMATION

Immediately consult doctor if
increased
bruising,
blood
stained vomit/urine, dark bowel
actions,
nose
bleed,
headache/dizziness,
joint/muscle /stomach / back
pain, leg weakness/numbness.

Always attend for regular blood
tests (INR).

Ensure your doctor orders more
frequent
INRs
&
adjusts
warfarin dose when new
medications are started /
stopped, regular medication
doses are changed or with
reduced oral intake, illness and
vomiting.
Indication: …………………………………
Recommended INR: ……………………..
Expected Duration
of Treatment: …………………………….
Doctor: ……………………………………
Please Show This Card When
Presenting
to
Hospital
&/or
Emergency
Department,
Doctor,
Pharmacist or Dentist
If this Card is Found Please Return
to Liverpool Hospital Health
Service Pharmacy Department (02)
98283000
Page 8 of 10
WARFARIN: IMPORTANT INFORMATION FOR PATIENTS
WARFARIN ALERT CARD
Please present this Card when attending for treatment or seeking advice from your doctor,
dentist, pharmacist, physiotherapist, occupational therapist or any other health practitioner.
INR BLOOD TESTS
After leaving hospital, your next INR test is due on: …………………………………… This test
can be performed by your local doctor, pathology laboratory. You must contact your Doctor
when you have your INR results to find out what your Warfarin dose should be.
WARFARIN
Warfarin belongs to a class of drugs known as anticoagulants, or ‘blood thinners’. It helps to
prevent the blood from clotting in your blood vessels (ie. arteries and veins).
There are TWO different brands of Warfarin, they are Marevan and Coumadin. (Yarrawonga
District Health Service only prescribes the Coumadin brand.)
Always use the same brand of Warfarin: do not swap Coumadin tablets for Marevan.
WARFARIN DOSE
Warfarin is prescribed in milligrams. There are THREE different strengths of Coumadin:



1mg Tablets: Light Tan Colour
2mg Tablets: Lavender Colour
5mg Tablets: Green Colour
Ensure you take the correct tablets by checking the colour and strength against the
dose prescribed by your doctor.
ADMINISTRATION TIME
Take the exact number of tablets prescribed under your doctor’s direction at the same time
each day. If you forget your regular daily dose, you may take that dose within 2-3 hours of
missing that dose. If 2-3 hours has already passed, please consult your doctor. Do not take
an extra dose on the next day.
LABORATORY TESTS
The safety and effectiveness of Warfarin must be monitored regularly by performing INR
blood tests. Your doctor will order these to ensure the correct amount of Warfarin is
prescribed.
The INR blood level should be measured every 1 to 2 days if:





Starting warfarin for the first time.
Starting warfarin again, after having stopped it for a surgical procedure or other reason.
Starting on new medicines or herbal preparations that are prescribed by your doctor or
bought over-the-counter (without a prescription).
Stopping any prescribed or over-the-counter medicines or herbal preparations.
You are eating less for any reason (eg. with illness, vomiting, fasting for religious
reasons).
Consult your doctor & request an INR test if any of the above situations arise.
Page 9 of 10
After your INR test:
1.
2.
Phone your doctor (or the laboratory where the test is performed) on the day
your INR test is taken, and ask what, if any, dose adjustment is required.
Write down the INR result and any dosage changes in your record book.
Once the INR result is stable, your INR may be monitored less frequently (usually
once every two to four weeks, depending upon your particular situation).
OTHER MEDICATIONS
Other medications may change the blood-thinning effect of warfarin. This includes
medicines that are prescribed by your doctor or bought over-the-counter without a
prescription (eg. Aspirin, cold and cough mixtures, laxatives, antacids, herbal, and
vitamin preparations).
If you take warfarin, please tell your doctor all the medicines and other
remedies you are taking. Please ensure you read the section on Laboratory
tests and the need for regular INR test if you start, stop, or change
medications.
DIETARY PRINCIPLES
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Avoid crash dieting and binge eating. Use alcohol in moderation - avoid binge
drinking.
If taking laxatives or antacids, use in moderation and discuss this with your
doctor.
Green leafy vegetables may be eaten in moderation (these contain Vitamin K,
which opposes the action of Warfarin).
SURGICAL PROCEDURES
Your Warfarin may need to be stopped well before your surgery, dental work or
medical procedure (eg. Gastroscopy, colonoscopy, arthroscopy, emergency room
treatment after injury). At your first appointment please tell the doctor/dentist
performing your procedure that you are taking warfarin.
TRAVEL
Please ensure that your doctor provides you with a letter, and arranges for an INR
test and follow up with another doctor during your period of travel.
PREGNANCY
Warfarin should not be taken if you are pregnant, or are considering becoming
pregnant. If you become pregnant, you must report to your doctor immediately.
Please discuss an alternative type of anticoagulant therapy with your doctor.
SIGNS OF BLEEDING
Warfarin acts as a blood thinner and therefore it increases the risk of bruising and
bleeding.
Please attend your doctor or a hospital emergency department immediately if
you experience:
Less Obvious Signs:
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Red or dark urine or bowel actions.
Blood-stained vomit.
Joint, muscle, stomach or back pain.
Leg weakness or numbness.
Headache, visual disturbance or dizziness.
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Obvious Bleeding:
Bruising:
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ANY OTHER UNUSUAL FEATURES.
Any bleeding that does not stop by itself (eg prolonged bleeding
from cuts).
Nosebleeds.
Bleeding of gums from brushing.
Increased menstrual flow, vaginal bleeding.
Increased or new appearance of black or blue bruise marks.
Acknowledgement to the Yarrawonga District Health Service Pharmacy Department,
the Alfred Hospital in Melbourne, and Armadale Hospital.
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