1Assistant Professor of Cardiovascular Surgery, Faculty of Medicine, Mashhad University of Medical Sciences, Atherosclerosis Prevention Research Center, Imam Reza Hospital. Iran.
2Associated Professor of Cardiovascular Surgery, Faculity of Medicine, Mashhad University of Medical Sciences, Atherosclerosis Prevention Research Center, and Imam Reza Hospital. Iran.
3Assistant Professor of Cardiovascular Surgery, Faculty of Medicine, Hamadan University of Medical Sciences. Iran.
4Head nursing of cardiac surgery operation room, Imam Reza Hospital. Iran
5Medical student ,Faculity of Medicine, Mashhad University of Medical. Iran.
6Assistant Professor of Cardiovascular Surgery, Faculity of Medicine, Mashhad University of Medical Sciences, Atherosclerosis Prevention Research Center, Imam Reza Hospital. Iran.
Introduction: Herbal medicine is usually safe and popular in Iranian communities. Peppermint herbal products may interact with warfarin, which is an essential lifelong drug used in patients with prosthetic heart valves. Herein, we report a case of possible interaction between warfarin and peppermint herbal tea. Materials and Methods: The databases of MEDLINE, Scopus, and Google Scholar (from June 1966 to July 2014) were searched with the medical subject heading (Mesh) “warfarin” combined with “herbal medicine” and “peppermint tea’’. Case Presentation: We described a 68-year-old woman who was on warfarin treatment due to bileaflet aortic mechanical, and mitral valve replacement presented with severe dyspnea in the setting of large obstructive mitral valve prosthesis thrombus diagnosed by echocardiography. Therefore, cardiac surgery was conducted in the emergent setting. Warfarin was started the day after the procedure. She developed melena with a volatile and elevated international normalized ratio (INR) of 4.8 and prothrombin time > 30 s on the 7th post-operation day. She reported no changes in drug or dietary habits except for drinking high amounts of peppermint tea the day before. After the discontinuation of warfarin and medical consultation for gastrointestinal bleeding, the INR level decreased to 1.8 within two days. Conclusion: Consumption of peppermint herbal products are usually safe, however, caution should be taken with patients under warfarin treatment. Full disclosure for patients on anticoagulant treatment is necessary before discharge and during clinical follow-up.