Toggle Main Menu Toggle Search

Open Access padlockePrints

Assessment of the efficacy of a novel tailored vitamin K dosing regimen in lowering the International Normalised Ratio in over-anticoagulated patients: A randomised clinical trial

Lookup NU author(s): Dr Emma KampourakiORCiD, Dr Peter Avery, Dr Hilary Wynne, Dr Tina Biss, Dr John Hanley, Dr Katherine Talks, Professor Farhad Kamali



This is the authors' accepted manuscript of an article that has been published in its final definitive form by Blackwell Publishing Ltd, 2017.

For re-use rights please refer to the publisher's terms and conditions.


© 2017 John Wiley & Sons Ltd Current guidelines advocate using fixed-doses of oral vitamin K to reverse excessive anticoagulation in warfarinised patients who are either asymptomatic or have minor bleeds. Over-anticoagulated patients present with a wide range of International Normalised Ratio (INR) values and response to fixed doses of vitamin K varies. Consequently a significant proportion of patients remain outside their target INR after vitamin K administration, making them prone to either haemorrhage or thromboembolism. We compared the performance of a novel tailored vitamin K dosing regimen to that of a fixed-dose regimen with the primary measure being the proportion of over-anticoagulated patients returning to their target INR within 24 h. One hundred and eighty-one patients with an index INR > 6·0 (asymptomatic or with minor bleeding) were randomly allocated to receive oral administration of either a tailored dose (based upon index INR and body surface area) or a fixed-dose (1 or 2 mg) of vitamin K. A greater proportion of patients treated with the tailored dose returned to within target INR range compared to the fixed-dose regimen (68·9% vs. 52·8%; P = 0·026), whilst a smaller proportion of patients remained above target INR range (12·2% vs. 34·0%; P < 0·001). Individualised vitamin K dosing is more accurate than fixed-dose regimen in lowering INR to within target range in excessively anticoagulated patients.

Publication metadata

Author(s): Kampouraki E, Avery PJ, Wynne H, Biss T, Hanley J, Talks K, Kamali F

Publication type: Article

Publication status: Published

Journal: British Journal of Haematology

Year: 2017

Volume: 178

Issue: 5

Pages: 800-809

Print publication date: 01/09/2017

Online publication date: 02/08/2017

Acceptance date: 29/03/2017

Date deposited: 30/11/2017

ISSN (print): 0007-1048

ISSN (electronic): 1365-2141

Publisher: Blackwell Publishing Ltd


DOI: 10.1111/bjh.14777


Altmetrics provided by Altmetric


Funder referenceFunder name
UK National Institute for 439 Health Research (NIHR)