Given Too Much Warfarin – Can I Claim Compensation?

Being given too much warfarin can be serious. Warfarin is an anticoagulant – commonly described as a blood thinner – which is prescribed to prevent and treat blood clots.

The very property that makes warfarin effective can also make a dosage error dangerous. Too much warfarin can increase the risk of excessive bleeding, including potentially serious internal bleeding.

If you have been given too much warfarin, prescribed the wrong dose or suffered injury following inadequate monitoring, you may be entitled to investigate a medical negligence claim.

Why is the correct warfarin dose so important?

Warfarin does not have one standard dose suitable for everyone.

Patients taking it require regular blood tests measuring their International Normalised Ratio (INR). The result helps clinicians determine whether the blood is clotting within the intended therapeutic range and whether the dose needs adjusting.

The NHS guidance on warfarin confirms that regular INR testing is required and that doses may change according to the results.

Specialist Pharmacy Service guidance also recommends more frequent monitoring in circumstances including poor anticoagulation control, increased bleeding risk and the introduction of medicines which may interact with warfarin.

What happens if you are given too much warfarin?

The principal risk is excessive bleeding.

This could include blood in the urine or stools, unexplained bruising, prolonged nosebleeds, vomiting or coughing blood and, in serious cases, symptoms associated with bleeding within the brain.

An excessive dose does not automatically establish negligence. The question is why the excessive anticoagulation occurred and whether reasonable care would have prevented it.

What warfarin errors could lead to a claim?

Potential examples include:

• prescribing an incorrect dose;
• a pharmacy dispensing the wrong strength;
• failure to arrange appropriate INR monitoring;
• failing to act upon an abnormal INR result;
• incorrect instructions being given to the patient;
• failure to consider an important drug interaction; or
• administering another patient’s dose.

NHS Resolution has identified anticoagulants amongst the medication groups most commonly implicated in medication-error incidents.

Can I claim for a warfarin overdose?

Potentially, but there must ordinarily be an injury caused by the negligent error.

For example, if an incorrect warfarin dose caused significant bleeding requiring hospital admission, blood transfusion or further treatment, the circumstances may justify investigation.

The legal assessment normally considers two issues: was the treatment negligent, and did that negligence cause or materially contribute to the injury?

What evidence should I keep?

Keep any medication packaging, prescription information, anticoagulation records and correspondence concerning the incident.

Your GP, hospital, pharmacy and anticoagulation clinic records may subsequently provide important evidence showing the dose prescribed, INR results and how clinicians responded.

Speak to Hutcheon Law about a warfarin medication error

If you have suffered injury after being given too much warfarin, prescribed an incorrect dose or inadequately monitored, Hutcheon Law can investigate whether you may have grounds for compensation.

Read more about our medication error prescription or contact us here

This article provides general information about the law in England and Wales. It is not a substitute for individual legal or medical advice. Patients should not stop or alter prescribed medication without appropriate medical guidance.