{"id":5386,"date":"2026-02-20T11:16:56","date_gmt":"2026-02-20T09:16:56","guid":{"rendered":"https:\/\/cvja.co.za\/journal\/?p=5386"},"modified":"2026-03-13T14:18:38","modified_gmt":"2026-03-13T12:18:38","slug":"cvja-2025-090","status":"publish","type":"post","link":"https:\/\/cvja.co.za\/journal\/cvja-2025-090\/","title":{"rendered":"Case report of a patient with acenocoumarol resistance following therapy for infective endocarditis with rifampicin and gentamicin combination therapy"},"content":{"rendered":"
\r\n
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\r\n \r\n \r\nM Luszczyn, K Nowakowska, I Kolasa, B Makowski\r\n<\/div> \r\n<\/div> \r\n
\r\n Copyright:<\/strong> Clinics Cardive Publishing (Pty) Ltd. publisher\r\n of Cardiovascular Journal of Africa.<\/div>\r\n
<\/div> \r\n
\r\n
\r\n Abstract \r\n <\/div> \r\n \r\n
\r\n \r\n \r\n \r\n \r\nVitamin K antagonists (VKAs) are essential for anticoagulation in patients with mechanical heart valves, but are affected by drug interactions, particularly with rifampicin \u2013 a potent inducer of CYP2C9 that accelerates VKA metabolism and destabilises INR levels. A 48-year-old male with multiple aortic valve replacements and infective endocarditis required rifampicin therapy post-surgery. Despite escalating doses of warfarin and acenocoumarol, therapeutic INR levels were not achieved, requiring low molecular weight heparin (LMWH) bridging. INR stabilisation occurred only after discontinuing rifampicin, with a drastic reduction in VKA dose requirements. Managing anticoagulation in patients on VKAs and rifampicin remains challenging due to rapid metabolism and INR fluctuations. Close INR monitoring, dose adjustments and alternative strategies, such as twice-daily VKA dosing or LMWH bridging, are crucial for maintaining therapeutic anticoagulation.\r\n
\r\n \r\n\r\n \r\n <\/div> \r\n <\/div> \r\n \r\n \r\n
\r\n \r\n Keywords:<\/strong> \r\n \r\n vitamin K antagonists, rifampicin, CYP2C9, INR stabilisation, mechanical heart valve<\/strong> \r\n \r\n <\/div> \r\n \r\n
\r\n \r\n Submitted:<\/strong> January 21, 2025; \r\n Accepted:<\/strong> February 18, 2025; \r\n Published:<\/strong> February 20, 2026
\r\n Cardiovasc J Afr 2025; 37<\/b>: 8-9<\/em>\r\n
Volume 37, Issue 1<\/strong>
\r\n <\/div> \r\n \r\n
\r\n DOI Citation Reference: dx.doi.org\/10.5830\/CVJA-2025-090 \r\n <\/div> \r\n \r\n
\r\n\r\nThe Students Society of Interventional Cardiology, Collegium Medicum, University of Zielona Gora, Zielona Gora, Poland\r\n<\/strong>
\r\nM Luszczyn
\r\nK Nowakowska
\r\nB Makowski\r\n\r\n

\r\n\r\nWSSP ZOZ Nowa Sol, Nowa Sol, Poland\r\n<\/strong>
\r\nI Kolasa
\r\nB Makowski\r\n\r\n

\r\n\r\nDepartment of Interventional Cardiology and Cardiac Surgery, Collegium Medicum, University of Zielona Gora, Zielona Gora, Poland\r\n<\/strong>
\r\nZielona Gora
\r\nB Makowski\r\n\r\n

\r\n \r\n\r\n [soshsc hide=\"logged\"]\r\n You need to be logged in to view and download<\/a> the full text PDF version. Register for a free account?<\/a><\/strong>

[\/soshsc]\r\n \r\n \r\n \r\n <\/div>\r\n \r\n<\/div>","protected":false},"excerpt":{"rendered":"

Vitamin K antagonists (VKAs) are essential for anticoagulation in patients with mechanical heart valves, but are affected by drug interactions, particularly with rifampicin \u2013 a potent inducer of CYP2C9 that accelerates VKA metabolism and destabilises INR levels.<\/p>\n","protected":false},"author":4,"featured_media":0,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"_monsterinsights_skip_tracking":false,"_monsterinsights_sitenote_active":false,"_monsterinsights_sitenote_note":"","_monsterinsights_sitenote_category":0,"footnotes":""},"categories":[56,109],"tags":[],"class_list":["post-5386","post","type-post","status-publish","format-standard","hentry","category-case-reports","category-volume-37-issue-1"],"yoast_head":"\nCase report of a patient with acenocoumarol resistance following therapy for infective endocarditis with rifampicin and gentamicin combination therapy - Cardiovascular Journal of Africa<\/title>\n<meta name=\"description\" content=\"Vitamin K antagonists (VKAs) are essential for anticoagulation in patients with mechanical heart valves, but are affected by drug interactions, particularly with rifampicin \u2013 a potent inducer of CYP2C9 that accelerates VKA metabolism and destabilises INR levels.\" \/>\n<meta name=\"robots\" content=\"index, follow, max-snippet:-1, max-image-preview:large, max-video-preview:-1\" \/>\n<link rel=\"canonical\" href=\"https:\/\/cvja.co.za\/journal\/cvja-2025-090\/\" \/>\n<meta property=\"og:locale\" content=\"en_US\" \/>\n<meta property=\"og:type\" content=\"article\" \/>\n<meta property=\"og:title\" content=\"Case report of a patient with acenocoumarol resistance following therapy for infective endocarditis with rifampicin and gentamicin combination therapy - 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