{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2025,11,7]],"date-time":"2025-11-07T14:10:00Z","timestamp":1762524600075,"version":"build-2065373602"},"reference-count":12,"publisher":"SMC Media","issue":"11","content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":[],"abstract":"<jats:p>Background:\u00a0Thyroid function abnormalities can alter the pharmacokinetics of various drugs, including warfarin. Although a few case reports in the literature have highlighted this phenomenon, ours is the first in the region. Case description:\u00a0We report a case of a 40-year-old female known to have uncontrolled Graves\u2019 disease due to non-compliance with medication and follow-up, with a history of mitral valve replacement, on warfarin 3 mg daily. She presented with a headache and was found to have a subdural haematoma and an INR of 10.58. It was observed that as she was approaching euthyroid state with antithyroid treatment; her warfarin requirement slowly increased to maintain the target INR. Conclusion:\u00a0Our case highlights the relationship between hyperthyroidism and exaggerated response to vitamin K antagonists. Literature suggests there is an amplified response to warfarin in a hyperthyroid state. Therefore, a timely and close follow-up of INR and thyroid function test is warranted in patients with hyperthyroidism on anti-coagulation with warfarin.<\/jats:p>","DOI":"10.12890\/2025_005822","type":"journal-article","created":{"date-parts":[[2025,10,20]],"date-time":"2025-10-20T10:14:22Z","timestamp":1760955262000},"source":"Crossref","is-referenced-by-count":0,"title":["Uncontrolled Graves\u2019 disease as a driver of amplified warfarin sensitivity"],"prefix":"10.12890","volume":"12","author":[{"ORCID":"https:\/\/orcid.org\/0009-0008-8550-772X","authenticated-orcid":false,"given":"Esraa Abdulla Ibrahim","family":"Ockba","sequence":"first","affiliation":[{"name":"Internal Medicine, Dubai Health, Dubai, United Arab Emirates; Mohammed Bin Rashid University, Postgraduate Medical Education Division, Dubai, United Arab Emirates"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0009-0009-2958-9393","authenticated-orcid":false,"given":"Manar Elfatih","family":"Mohamed","sequence":"first","affiliation":[{"name":"Internal Medicine, Dubai Health, Dubai, United Arab Emirates; Mohammed Bin Rashid University, Postgraduate Medical Education Division, Dubai, United Arab Emirates"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-3632-4336","authenticated-orcid":false,"given":"Khadija","family":"Hafidh","sequence":"first","affiliation":[{"name":"Internal Medicine, Dubai Health, Dubai, United Arab Emirates"}],"role":[{"role":"author","vocabulary":"crossref"}]}],"member":"10397","published-online":{"date-parts":[[2025,10,20]]},"reference":[{"key":"10.12890\/2025_005822_ref1","doi-asserted-by":"crossref","unstructured":"Erem C. Thyroid disorders and hypercoagulability. Semin Thromb Hemost 2011;37:17\u201326. doi:10.1055\/s-0030-1270067","DOI":"10.1055\/s-0030-1270067"},{"key":"10.12890\/2025_005822_ref2","doi-asserted-by":"crossref","unstructured":"Elbers LPB, Fliers E, Cannegieter SC. The influence of thyroid function on the coagulation system and its clinical consequences. J Thromb Haemos 2018;16:634\u2013645. doi: 10.1111\/jth.13970","DOI":"10.1111\/jth.13970"},{"key":"10.12890\/2025_005822_ref3","doi-asserted-by":"crossref","unstructured":"Antonijevic N, Matic D, Beleslin B, Mikovic D, Lekovic Z, Marjanovic M, et al. The influence of hyperthyroidism on the coagulation and on the risk of thrombosis. J Clin Med 2024;13:1756. doi:10.3390\/jcm13061756","DOI":"10.3390\/jcm13061756"},{"key":"10.12890\/2025_005822_ref4","doi-asserted-by":"crossref","unstructured":"Howard-Thompson A, Luckey A, George C, Choby BA, Self TH. Graves\u2019 disease and treatment effects on warfarin anticoagulation. Case Rep Med 2014;2014:292468. doi: 10.1155\/2014\/292468","DOI":"10.1155\/2014\/292468"},{"key":"10.12890\/2025_005822_ref5","doi-asserted-by":"crossref","unstructured":"Akin F, Yaylali GF, Bastemir M, Yapar B. Effect of methimazole on warfarin anticoagulation in a case of Graves\u2019 disease. Blood Coagul Fibrinolysis 2008;19:89\u201391. doi: 10.1097\/MBC.0b013e3282f0981f","DOI":"10.1097\/MBC.0b013e3282f0981f"},{"key":"10.12890\/2025_005822_ref6","doi-asserted-by":"crossref","unstructured":"Ansell J, Hirsh J, Hylek E, Jacobson A, Crowther M, Palareti G. Pharmacology and management of the vitamin K antagonists: American College of Chest Physicians Evidence-Based Clinical Practice Guidelines (8th Edition). Chest 2008;133:160S\u2013198S. doi: 10.1378\/chest.08-0670","DOI":"10.1378\/chest.08-0670"},{"key":"10.12890\/2025_005822_ref7","doi-asserted-by":"crossref","unstructured":"Lee JE, Ryu DH, Jeong HJ, Kim JH, Jun JE, Kim JS, et al. Extremely elevated international normalized ratio of warfarin in a patient with CYP2C9*1\/*3 and thyrotoxicosis. J Korean Med Sci 2014;29:1317\u20131319. doi:10.3346\/jkms.2014.29.9.1317","DOI":"10.3346\/jkms.2014.29.9.1317"},{"key":"10.12890\/2025_005822_ref8","doi-asserted-by":"crossref","unstructured":"Wang M, Zeraatkar D, Obeda M, et al. Drug\u2013drug interactions with warfarin: A systematic review and meta-analysis. Br J Clin Pharmacol 2021;87:4051\u20134100. doi: 10.1111\/bcp.14833","DOI":"10.1111\/bcp.14833"},{"key":"10.12890\/2025_005822_ref9","doi-asserted-by":"crossref","unstructured":"Lilihata G, Saputra C, Yaniarti D, Soerarso R. Hyperthyroidism in severe mitral regurgitation post mechanical mitral valve replacement: the effect on warfarin anticoagulation. Cardiovasc Endocrinol Metab 2020;10:146\u2013148. doi: 10.1097\/XCE.0000000000000233","DOI":"10.1097\/XCE.0000000000000233"},{"key":"10.12890\/2025_005822_ref10","doi-asserted-by":"crossref","unstructured":"Bucerius J, Ezziddin S, Brockmann H, Palmedo H, Biersack HJ. Impact of thyroid metabolism on the course of INR levels in a patient with systemic anticoagulation suffering from amiodarone-induced thyrotoxicosis. Exp Clin Endocrinol Diabetes 2007;115:606-609. doi: 10.1055\/s-2007-984439","DOI":"10.1055\/s-2007-984439"},{"key":"10.12890\/2025_005822_ref11","doi-asserted-by":"crossref","unstructured":"Busenbark LA, Cushnie SA. Effect of Graves\u2019 disease and methimazole on warfarin anticoagulation. Ann Pharmacother 2006;40:1200\u20131203. doi: 10.1345\/aph.1G422","DOI":"10.1345\/aph.1G422"},{"key":"10.12890\/2025_005822_ref12","doi-asserted-by":"crossref","unstructured":"Otto CM, Nishimura RA, Bonow RO, Carabello BA, Erwin JP 3rd, Gentile F, et al. 2020 ACC\/AHA Guideline for the Management of Patients With Valvular Heart Disease: Executive Summary. A Report of the American College of Cardiology\/American Heart Association Joint Committee on Clinical Practice Guidelines. Circulation 2020;143. doi: 10.1161\/CIR.0000000000000923","DOI":"10.1161\/CIR.0000000000000932"}],"container-title":["European Journal of Case Reports in Internal Medicine"],"original-title":[],"link":[{"URL":"https:\/\/www.ejcrim.com\/index.php\/EJCRIM\/article\/download\/5822\/4901","content-type":"text\/html","content-version":"vor","intended-application":"text-mining"},{"URL":"https:\/\/www.ejcrim.com\/index.php\/EJCRIM\/article\/download\/5822\/4902","content-type":"application\/pdf","content-version":"vor","intended-application":"text-mining"},{"URL":"https:\/\/www.ejcrim.com\/index.php\/EJCRIM\/article\/download\/5822\/4902","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2025,11,7]],"date-time":"2025-11-07T14:05:08Z","timestamp":1762524308000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.ejcrim.com\/index.php\/EJCRIM\/article\/view\/5822"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2025,10,20]]},"references-count":12,"journal-issue":{"issue":"11","published-online":{"date-parts":[[2025]]}},"URL":"https:\/\/doi.org\/10.12890\/2025_005822","relation":{"has-manifestation":[{"id-type":"other","id":"1-131-5822-g4901","asserted-by":"subject"},{"id-type":"other","id":"1-131-5822-g4902","asserted-by":"subject"}],"is-part-of":[{"id-type":"other","id":"1-131","asserted-by":"subject"}]},"ISSN":["2284-2594"],"issn-type":[{"type":"electronic","value":"2284-2594"}],"subject":[],"published":{"date-parts":[[2025,10,20]]}}}