Anticoagulation Service
This leaflet will provide you with important information about the
anticoagulant service, how it is provided, what to expect when
you attend the clinic, and important information about your
anticoagulant treatment. Please take a few minutes to read
through all sections of this leaflet. If you have any questions, or
need help to understand any of this leaflet, please ask your
anticoagulant specialist nurse.
If you do not take your anticoagulation treatment as prescribed,
You may be putting yourself at serious risk of harm
Working in partnership with the anticoagulant nurse
Who needs anticoagulation treatment?
Anticoagulant drugs help prevent the formation of harmful clots in blood vessels
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 Treat an existing clot
There are many conditions requiring anticoagulation treatment, which include:
 Deep vein thrombosis (DVT - an abnormal clot in a deep vein)
 Atrial fibrillation (an irregular heart rate)
 Pulmonary embolism (a blood clot in the lungs)
 Mechanical valve fitted
What is an anticoagulant?
Anticoagulants are prescribed drugs that may be given as a tablet or sometimes an
injection. The most widely used tablet is called warfarin.
Why do I need to attend an outpatient appointment for anticoagulation
treatment?
You will need regular blood tests to see whether the prescribed oral anticoagulant
dose is maintaining your INR (international normalised ratio) within range. INR is the
measurement of the time it takes for the blood to clot. The normal range is 1.0 –1.2,
so if your INR is 2, the blood is taking twice as long as normal to clot. Your doctor will
advise on the required INR range for your medical condition. Anticoagulant tablets
may take several days to work and it may take one, two or three weeks before your
blood test results show the required level. It is very important that you continue to
take your treatment, even if you do not feel any different.
What will happen at the first appointment?
We will post you details of the date, time and venue of your first appointment which
will always be at Barnet Hospital. Follow up appointments could be organised in an
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out reach site if there is one nearer to you. At your first appointment you will see a
specialist nurse who will discuss your medical condition with you, arrange for a blood
test and discuss the medication you need to take. You will be able to ask the nurse
any questions you may have at this appointment.
You will need to provide the nurse with a list of all your medication including whether
you are on:
 the contraceptive pill
 Hormone replacement therapy
as these increase the risk of a blood clot forming.
The ‘mini pill’ may be suitable but needs to be discussed with the person who
prescribed it. If you are not sure who to ask, speak to your own GP.
You will also need to tell the nurse if you are taking any herbal remedies or
multivitamins, whether you smoke and the amount of alcohol you drink on a
weekly/daily basis. It is important that you are as honest with the nurse as possible,
as the treatment you are given will depend upon the answers you give.
You will be given a yellow form which is for you to keep safely. This will be used to
record your:
 Appointments
 Test results
 Dosage
What if I am having other medical or dental treatment?
If you are having other medical or dental treatment, show the doctor your latest
dosage instruction letter. It is very important that the doctor or dentist treating you
knows that you are on anticoagulant therapy. Provide the dentist with the
Anticoagulation Clinic’s number so that the dentist can get in touch with the Team if
there are any queries.
Tell your doctor or dentist if you are:
 Pregnant or planning to become pregnant
 Due to have an operation
 Immobilised in bed for any reason, or your leg is immobilised (eg in plaster
due to an injury or fracture)
All these can increase the risk of a blood clot forming. In pregnancy, warfarin can
harm the unborn baby, so if you think you may be at risk of becoming pregnant whilst
on this treatment, please speak to the specialist nurse or your own GP for advice
before starting the course.
How often will I need to attend clinic?
At first, you will need to attend once or twice a week. We understand it might be
very difficult to make the time to attend the Clinic, but at the beginning of your
treatment it is very important to your health and well being that you are checked
regularly. Once we have found the correct anticoagulation dose for you, you will not
need to attend so often. As and when your INR stabilises you may only need to
attend every four, eight or 12 weeks. However if the INR becomes unstable due to
changes in medication or medical condition, you will need to be monitored at least
once a week or whatever frequency that is required.
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What will happen at future appointments?
You must inform the clinic if you are unable to attend an appointment so your
appointment can be given to another patient and we can organise a new
appointment for you.
The clinics are very busy, with up to 80 patients attending each one. We have
introduced an appointments system at Barnet & Chase Farm Hospital to avoid
patients having to wait a long time at the busiest periods, such as at the beginning or
the end of the day. We did this in response to feedback we received from patients.
We will do our very best to allocate appointments to suit the particular needs of
patients. However this may not be possible if the majority of appointments for a
particular clinic have already been allocated.
To keep your waiting time to a minimum, please note the following:
 You must inform us of anything that affects your treatment or appointments
(eg, changes to medication, holiday plans, change of address, hospital
admission). Write these down on a piece of paper, together with your name,
hospital number and appointment date. Staple this to your INR request
form/ Write the message on the INR request form where there is a space for
your messages.
 When you arrive at the clinic, report to the receptionist and wait to be called
for your appointment
 You will be called for your blood test, be ready to take off your coat or jacket.
After your blood test, you may leave the clinic. Your dosage instruction letter will be
posted to you stating the dose of anticoagulant tablets you need to take and the date
and time of your next appointment. Please do not telephone the clinic to ask if your
dose has changed. We will phone you if you need to change your dosage urgently,
otherwise carry on with the current dose until your dosage instruction letter arrives in
the post.
Keeping your clinic appointments
It is vital that you continue to take your anticoagulation treatment until you have been
advised to stop. The reason for visiting the clinic is to check your INR levels and to
change your dose, if and when it might be necessary. If you fail to keep your
appointment you will not be able to attend the clinic again without a pre-booked time.
Therefore, if you are unable to keep your appointment please contact us with as
much notice as possible so that your place can be given to someone else and an
alternative appointment can be arranged. If you fail to keep three consecutive
appointments, you GP will be informed.
For health and safety reasons we are limited to the amount of patients we can see in
each clinic, so keeping your appointment will help us to run our busy clinics as
smoothly as possible for everyone.
Points to remember for patients having their blood test in the GP surgery/
district nurse/nursing home /residential home/out patients blood test unit
 We would prefer the samples to be taken on Monday/Tuesday but never on a
Friday.
 These patients will always be given a Tuesday date as the next appointment.
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
The result of the test, recommended dose of anticoagulant and date of next test
will be recorded in the dosage instruction letter and sent by post to the patient.
We will telephone the patient/carer if we recommend that the patient stops warfarin
for one or more days because of high INR. We will not routinely telephone all
changes in doses.
When do you need to see the anticoagulant nurse specialist?
You will see the anticoagulant specialist nurse:
 For your first appointment
 Before you stop anticoagulant therapy
 If you ask to see someone because of a medical problem linked to your
anticoagulant therapy
 The nurse requests you to attend for consultation
Are there any risks associated with anticoagulant therapy?
As warfarin works by delaying the times it take to clot, the blood patients on warfarin
may experience a slight increase in bruising and minor bleeding, for example from:
 Nose bleeds
 Bleeding gums
 Heavy periods
 Blood in urine or stools
What else can I do to help reduce the risk from blood clots?
There are no medical alternatives, but there are many things that you can do to help
prevent a blood clot forming, for example:
 Give up smoking. This may be very difficult, but there are smoking cessation
clinics held at GP clinics.
 Avoid or reduce drinking alcohol as this causes dehydration and increases the
viscosity of your blood.
 Take regular exercise - this can be gentle and based in your own home
 If taking a long haul flight, exercise your feet every half hour and walk up and
down the aisle every couple of hours. Wear compression stockings and drink
plenty of non-alcoholic fluids
Information about warfarin
You will be given the initial prescription by your hospital. The hospital will only
issue 0.5mg, 1mg or 3mg of warfarin.
For future supplies of tablets please contact your GP. Make sure your GP has
adequate notice and take your yellow form to the surgery so that the GP can see that
you are being monitored
Tablets can be used in any combination to make up the required dose. For example,
if your warfarin dose is 6 / 7mg alternate days you can use two blue warfarin tablets
and one 0.5mg warfarin tablet. You are advised not to break the tablets. The dose
of warfarin you need to take will be on a printed dosage label in your dosage
instruction letter. If you are in doubt, contact the anticoagulation clinic.
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If you need any other information or advice, please contact:
Anticoagulation Support line
Monday- Friday 09.00- 17.00
Tel: 020 8216 4890 or
Tel: 020 8216 5330
Fax: 020 8216 4216
For appointment changes
Tel: 020 8216 4374 or
Tel: 020 8216 4143
Below is a useful website for people on warfarin or other anticoagulation therapy:
http://www.anticoagulationeurope.org
Anticoagulation out patient follow up clinic times
Barnet Hospital
Monday
8.00 -11.45am
Anticoagulation Clinic
Wednesday 8.00 -12.00pm
Follow up -Blood test unit level 0
Friday
8.00 -11.45am
(Appointment Time Allocated)
Barnet Hospital
All other blood test
Blood test unit- Level 0
(To book an appointment call: 0208
216 4394)
Fairbrook Medical Centre –
Wellswood Borehamwood
(To book an appointment call: 0208
953 4515 between 1400-1600)
Potters Bar Hospital
(To book an appointment call: 01707
653 286, Extension 4001)
Finchley Memorial Hospital
(To book an appointment call: 020
8349 7461)
Edgware Community Hospital
Pathology Department
Enfield
Chase Farm Hospital
Blood Test Unit
(Rear of Clocktower Building)
Cheshunt
Cheshunt Community Hospital
Monday to Friday 9.00 -1700
(Timed appointment only)
Tuesday
8.00-12.00
Wednesday 8.00-12.00
(Timed Appointment only)
Tuesday
8.30 -12.15
Wednesday 8.30 -12.15
Thursday
08.30-12.15
(Time appointment only)
Monday
8.00 -10.30am
(Timed Appointment only)
Tuesday 8.00 - 11.00am
Thursday 8.00 - 10.45am
(Walk-In)
Monday
12.00 - 5.00pm
Tuesday
12.00 - 5.00pm
Wednesday 12.00 - 5.00pm
Thursday
12.00 - 4.00pm
(Appointment Time Allocated)
Mon to Fri 8.00 -15.30am
(Walk-In and take a number)
Anticoagulation patients are advised
To have the test in the morning or
early afternoon and avoid Fridays
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