skip to main content

Warfarin Over-Anticoagulation — MFDS Part 1 MCQ

Instant feedback + full explanation. One question, done properly.

HardHuman DiseaseWarfarin Over-AnticoagulationMFDS Part 1

A 68-year-old patient taking long-term warfarin with a target INR of 2.0–3.0 attends for an elective dental extraction. Routine monitoring shows a laboratory-confirmed INR of exactly 8.0. The patient is clinically well, has no bleeding or bruising and has no additional high-risk features for bleeding. What is the most appropriate initial management of the anticoagulation?

Educational content. Not a substitute for clinical judgement or local policy.

Reveal the answer and explanation

Correct answer: D — Omit one or two warfarin doses and reduce the subsequent maintenance dose

An INR of exactly 8.0 without bleeding falls within the UK 5–8 management category: omit one or two warfarin doses, reduce the subsequent maintenance dose and arrange appropriate INR reassessment through the anticoagulation service. The cause of the elevated INR should also be investigated. Routine phytomenadione is reserved for an INR greater than 8.0 in an otherwise non-bleeding patient, so A is inappropriate at this exact threshold. Intravenous phytomenadione with prothrombin complex concentrate is used for major or life-threatening haemorrhage, excluding C. Continuing warfarin unchanged is unsafe, and an elective extraction should not proceed while the INR is markedly supratherapeutic.

Reference: Electronic Medicines Compendium, Warfarin 0.5 mg Tablets, Summary of Product Characteristics, section 4.9 Overdose, updated 21 May 2026. https://www.medicines.org.uk/emc/product/15258/smpc