A prospective randomized study to determine the optimal dose of intravenous vitamin K in reversal of over-warfarinization

Hung, A., Singh, S. and Tait, R.C. (2000) A prospective randomized study to determine the optimal dose of intravenous vitamin K in reversal of over-warfarinization. British Journal of Haematology, 109(3), pp. 537-539. (doi: 10.1046/j.1365-2141.2000.02001.x) (PMID:10886201)

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Abstract

The optimal management of asymptomatic overanticoagulated patients remains unknown. We measured international normalized ratio (INR), activated partial thromboplastin time (APTT) and prothrombin fragment 1 + 2 (F1 + 2) over 7 d in 24 asymptomatic or mildly haemorrhagic patients on warfarin with prolonged INR of > 7·0 who were randomized to receive 0·5 mg, 1 mg or 2 mg intravenous vitamin K. Of six severely overanticoagulated patients (INR > 9·5 with APTT ratio > 2), five failed to achieve an INR ≤ 4·0 on day 1, irrespective of vitamin K dose given. In the remaining 18 cases, an optimal response (INR 2–4 at day 1) was observed in 67% of those receiving 0·5 mg vitamin K, but only in 33% of those receiving 1 or 2 mg, the majority of whom developed an INR < 2·0. Our results support an optimal dose of 0·5 mg i.v. vitamin K for most overanticoagulated patients, with possibly a repeat dose in the small group of severely overanticoagulated patients.

Item Type:Articles
Status:Published
Refereed:Yes
Glasgow Author(s) Enlighten ID:Tait, Dr Robert
Authors: Hung, A., Singh, S., and Tait, R.C.
College/School:College of Medical Veterinary and Life Sciences > Institute of Cardiovascular and Medical Sciences
Journal Name:British Journal of Haematology
Publisher:Blackwell Science
ISSN:0007-1048
ISSN (Online):1365-2141

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