Case Report of International Journal of Case Reports
Major bleeding precipitated by interactions between antibiotics and warfarin: a case series
Luana Marchesan1, Raíssa Londero Chemello1, Vanessa Thomé1, Diego Chemello1,2
1.Department of Clinical Medicine, Health Science Center, Federal University of Santa Maria, Santa Maria, Brazil
2.Postgraduate Program in Health Science, Federal University of Santa Maria, Santa Maria, Brazil
Warfarin is a widely used anticoagulant agent with a large spectrum of indications for prevention and treatment of thromboembolic complications. Despite its low cost, warfarin and all other vitamin K antagonist (VKA) use has several limitations, including narrow therapeutic index requiring frequent laboratory monitoring to prevent complications related to under- and over-anticoagulation. The concomitant use of medications may alter the metabolism of warfarin by inducing or inhibiting the cytochrome P450-2C9, resulting in a decrease or increase in anticoagulant effect. In this setting, interactions between warfarin and antibiotics have been described. These interactions represent one of the problems with VKA use in the clinical setting. We aimed to report four cases where the prescription of antibiotics without proper control of anticoagulation levels led to major hemorrhagic complications.
Keywords: Anticoagulants; warfarin; drug interactions; hemorrhage; anti-bacterial agents
How to cite this article:
Luana Marchesan, Raíssa Londero Chemello, Vanessa Thomé, Diego Chemello. Major bleeding precipitated by interactions between antibiotics and warfarin: a case series. International Journal of Case Reports, 2018 2:22. DOI: 10.28933/ijcr-2018-05-0701.
1. Kuruvilla M, Gurk-Turner C. A review of warfarin dosing and monitoring. Proc (Bayl Univ Med Cent). 2001;14(3):305-306.
2. Schulman S, Beyth RJ, Kearon C, Levine MN. Hemorrhagic complications of anticoagulant and thrombolytic treatment: American College of Chest Physicians Evidence-Based Clinical Practice Guidelines (8th Edition). Chest. 2008;133(6 Suppl):257S-298S.
3. Clark NP, Delate T, Riggs CS, et al. Warfarin interactions with antibiotics in the ambulatory care setting. JAMA Intern Med. 2014;174(3):409-416.
4. Lane MA, Zeringue A, McDonald JR. Serious bleeding events due to warfarin and antibiotic co-prescription in a cohort of veterans. Am J Med. 2014;127(7):657-663.e652.
5. Baillargeon J, Holmes HM, Lin YL, Raji MA, Sharma G, Kuo YF. Concurrent use of warfarin and antibiotics and the risk of bleeding in older adults. Am J Med. 2012;125(2):183-189.
6. Ghaswalla PK, Harpe SE, Tassone D, Slattum PW. Warfarin-antibiotic interactions in older adults of an outpatient anticoagulation clinic. Am J Geriatr Pharmacother. 2012;10(6):352-360.
7. Haas S, Ten Cate H, Accetta G, et al. Quality of Vitamin K Antagonist Control and 1-Year Outcomes in Patients with Atrial Fibrillation: A Global Perspective from the GARFIELD-AF Registry. PLoS One. 2016;11(10):e0164076.
8. Hylek EM, Held C, Alexander JH, et al. Major bleeding in patients with atrial fibrillation receiving apixaban or warfarin: The ARISTOTLE Trial (Apixaban for Reduction in Stroke and Other Thromboembolic Events in Atrial Fibrillation): Predictors, Characteristics, and Clinical Outcomes. J Am Coll Cardiol. 2014;63(20):2141-2147.
9. Wan Y, Heneghan C, Perera R, et al. Anticoagulation control and prediction of adverse events in patients with atrial fibrillation: a systematic review. Circ Cardiovasc Qual Outcomes. 2008;1(2):84-91.
10. Kirchhof P, Benussi S, Kotecha D, et al. 2016 ESC Guidelines for the management of atrial fibrillation developed in collaboration with EACTS. Eur Heart J. 2016;37(38):2893-2962.
11. Vinereanu D, Lopes RD, Bahit MC, et al. A multifaceted intervention to improve treatment with oral anticoagulants in atrial fibrillation (IMPACT-AF): an international, cluster-randomised trial. Lancet. 2017;390(10104):1737-1746.