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Managing warfarin yourself

7 December 2010

A trial of people who are on the blood-thinning medication warfarin shows that patients who self-monitor their blood clotting ability, using an Internet-based expert system, have better outcomes than patients in routine care.

Warfarin treatment is prescribed to manage a variety of illnesses that are associated with the blood?s ability to clot. For example, some people find their blood clots too easily, causing conditions such as deep vein thrombosis.

When people are taking warfarin, a key test to ensure that the patient is receiving an appropriate dose is to measure how long it takes before the blood clots using the International Normalisation Ratio (INR).

In Ireland most people on warfarin currently visit their GP or a clinic to have their INR measured and they also need frequent visits to hospital. Could this be managed in a more convenient and less time-consuming way?

Dr Susan O Shea at Cork University Hospital worked with Fiona Ryan and Stephen Byrne in the School of Pharmacy, University College Cork, to trial an Internet-based system that would allow patients to manage their warfarin remotely. A total of 132 patients participated in the six month trial, testing their INR at home using a portable meter. The result and personal details were then entered on a secure Internet page, and instant feedback stated how much warfarin to take and when to perform the next test. The results speak for themselves:

Patients reported a higher percentage of blood tests within their desired range compared to people in routine care.

The number of people attending acute care was reduced.

Patients had more freedom, one person was even able to go on a world cruise.

More than 98% of patients surveyed preferred the patient self-testing.

The next step is to work towards implementing this effectively at a national level.


  • More frequent monitoring for patients on warfarin without additional time spent in the clinic or hospital.
  • Reduced pressure on acute care system.
  • Enhanced patient satisfaction.

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