According to current European Society of Cardiology guidelines, for staphylococcal prosthetic valve endocarditis, rifampicin should be one of the drugs used. However, there is a concomitant need for vitamin K antagonists in patients with mechanical prostheses. It is widely known that rifampicin interacts with vitamin K antagonists (VKA), and this interaction makes it difficult to maintain the INR (international normalized ratio) value in the therapeutic range. We present two clinical cases of staphylococcal prosthetic valve endocarditis patients. Two different strategies for dealing with adverse drug interactions have been applied. In the first case, the dose of warfarin was up-titrated until the optimal INR value was obtained. In the second case, due to the history of labile INR values, a decision was made to modify the dosage of warfarin, taking into account pharmacological aspects of drug interactions.

中文翻译：

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醋香香豆素与利福平联合用药治疗葡萄球菌性人工瓣膜心内膜炎的两种策略


根据现行欧洲心脏病学会指南，对于葡萄球菌性人工瓣膜心内膜炎，利福平应是使用的药物之一。然而，机械假肢患者同时需要维生素 K 拮抗剂。众所周知，利福平与维生素K拮抗剂（VKA）相互作用，这种相互作用使得INR（国际标准化比值）值难以维持在治疗范围内。我们介绍了两例葡萄球菌性人工瓣膜心内膜炎患者的临床病例。已经应用了两种不同的策略来处理不良药物相互作用。在第一种情况下，华法林的剂量被上调直至获得最佳 INR 值。在第二种情况下，由于 INR 值不稳定的历史，考虑到药物相互作用的药理学方面，决定修改华法林的剂量。