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：

---

葡萄球菌人工瓣膜性心内膜炎与阿霉素联用与利福平共同给药的两种策略

根据目前的欧洲心脏病学会指南，对于葡萄球菌人工瓣膜心内膜炎，应使用利福平作为药物之一。然而，伴随机械假体的患者也需要维生素K拮抗剂。众所周知，利福平与维生素K拮抗剂（VKA）相互作用，并且这种相互作用使得难以将INR（国际标准化比率）值维持在治疗范围内。我们介绍了两个葡萄球菌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应对药物不良相互作用。在第一种情况下，将华法林剂量调高直至获得最佳INR值。在第二种情况下，由于INR值不稳定的历史，因此决定修改华法林的剂量，