Anticoagulation service in North Devon

print_iconLeaflet number: 247
Review due date: May 2018


Who is the service for?

This service is for all patients taking warfarin, phenindione or acenocoumarol (anticoagulant). Patients are prescribed this type of medicine because there is a risk that they might develop damaging blood clots. This treatment may be started:

  • By your GP
  • While you were a patient at Northern Devon District hospital, or another hospital

Purpose of the anticoagulation clinic

We check how long it takes your blood to clot, using a measurement called an INR (International Normalised Ratio). It is important that your INR is kept within a certain range; this is done by adjusting your anticoagulant dose as needed, according to the blood test result. Keeping your INR within the correct range can help to prevent damaging blood clots. The results of your blood tests and your anticoagulant dose will be written in your small yellow book – your Oral Anticoagulation Therapy booklet.

Starting treatment in North Devon

If you have been prescribed warfarin, you will have been discharged with a box of 3mg and a box of 1mg warfarin tablets with instructions on what dose to take and when to have your next blood test. This will be written in the small yellow book. If this is not the case contact your prescriber.

If you have been discharged with enoxaparin (Clexane®) injections, you should continue using these until told to stop. Not all patients have these, so do not worry if this does not apply to you.

  • Please take your anticoagulant at, or after, 6pm each day. It can be taken with a meal or on an empty stomach, but please take it at around the same time each day if you can.
  • When you have a blood test to check your INR, take your small yellow book with you if you have it.

Your dosing may be handed over to your GP after a period of stabilisation if your surgery is equipped for this service. If this happens, you will be asked to give a small sample of blood from your fingertip. Please do not ring the anticoagulation clinic if your own GP manages your anticoagulant.

Queries about your yellow oral anticoagulant therapy book

We sometimes need to test your blood frequently, and the yellow oral anticoagulant book will not arrive in the post in time for the next blood test. Please keep a pad of paper supplied in your anticoagulation pack by the telephone, so that you can write down any dose changes and the next test dates when your GP surgery rings you.

If your yellow oral anticoagulant book is significantly delayed in being returned to you from the clinic (5 working days or more) and you have not been notified about your new dose or INR test date, please ring your GP or the anticoagulation clinic to ask for advice.

Patient responsibilities

In order to ensure you receive the best care possible, it is important for you to:

  • Attend your GP practice for blood tests as requested
  • Check your details are correct in your yellow anticoagulation book, especially your contact telephone number(s)
  • Carry an anticoagulation alert card with you at all times and take your yellow book with you to GP/hospital appointments and on holidays
  • Report any adverse events to a healthcare professional involved with your dosing e.g. bleeding, excessive bruising
  • Understand the risks and benefits of treatment
  • Be aware of the necessity of following treatment and monitoring guidance for your safety
  • Report any medication or dietary changes, illness or missed doses to the clinic pharmacists, or whoever looks after your warfarin via the small yellow book

Further information

The service in North Devon is run by pharmacists along with the consultant haematologist.

You can contact the service on 01271 370208 between 2.00pm and 5.30pm on week days only. An answerphone service is available.

Your blood sample is tested at the pathology laboratory at North Devon District Hospital. The lab contact number is 01271 322329.

The pharmacists in the anticoagulation clinic will use the INR result to decide on the dose of anticoagulant you should take and when you need your next test.

  • If your dose change is urgent, your GP surgery will ring you to advise you of the new dose and test date
  • If your dose can stay the same or it does not need changing straightaway, then your yellow book will be sent back in the post with these details written in. Until then you can continue to take the same dose as before.


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Last updated: October 10, 2019