Difficulty in warfarinisation

This advice is for those patients who are difficult to warfarinise.

Please:

check medication and compliance and document that clearly in the referral
ensure the patient is not taking vitamin K (e.g. some food supplements contain vitamin K). Ensure stable dietary intake of vitamin K-rich foods
check if the patient has had a recent large dose of vitamin K for warfarin reversal
ensure dose being given is appropriate for BMI.

Who to refer, who not to refer, how to refer

Who to refer:

Patients commenced on warfarin who show no increase in INR from baseline despite administration of doses of warfarin up to 15mg daily

Patients who have had therapeutic INRs that are subsequently difficult to dose – in such situations check compliance (and refer only if compliance appears satisfactory), and ensure dose being given appropriate for BMI

Who not to refer:

Patients who are non-compliant with their medications

How to refer:

Please refer via SCI Gateway

Primary care management

Primary care investigations

FBC
U&Es and LFTS

Last reviewed: 17/01/2025

Next review date: 17/01/2027

Author(s): Charlotte Robertson.