Rao Krishnamoorthy B, Pallaki Muralidhar, Tolbert Sandra R, Hornick Thomas R
Case Western Reserve University and University Hospitals of Cleveland, Cleveland, OH 44106, USA.
Ann Pharmacother. 2004 Jun;38(6):982-5. doi: 10.1345/aph.1D489. Epub 2004 Apr 14.
To report a case of probable azithromycin-warfarin drug interaction with enhanced hypoprothrombinemic effect of warfarin.
An 83-year-old African American man stabilized on warfarin therapy (10 mg on Wednesdays, 7.5 mg on other days) developed a prolonged prothrombin time one day after starting azithromycin 500 mg. The elevated prothrombin time normalized 3 days after azithromycin was discontinued. After the initial increase in the international normalized ratio, the absence of any significant confounding factors affecting the anticoagulant effect of warfarin in our patient and the numerous reports of such interactions indicate that an interaction between azithromycin and warfarin may have been responsible for the elevated prothrombin time seen in this patient. An objective causality assessment revealed that the adverse event was probably related to the combination of these drugs.
Azithromycin, unlike erythromycin and clarithromycin, is not known to inhibit the cytochrome P450 enzyme system and is presumed to be the macrolide of choice in patients already on warfarin. However, previously reported cases of azithromycin-warfarin interactions support the possibility that azithromycin does interact with warfarin, although the exact mechanism is not understood.
Azithromycin may interact with warfarin and enhance its hypoprothrombinemic effects. This effect may be delayed for 4-8 days after a course of azithromycin has been completed. Periodic monitoring of the prothrombin time is recommended when using azithromycin in patients taking warfarin.
报告一例可能存在阿奇霉素与华法林药物相互作用且增强了华法林低凝血酶原血症效应的病例。
一名83岁的非裔美国男性，华法林治疗已稳定（周三服用10毫克，其他日子服用7.5毫克），在开始服用500毫克阿奇霉素一天后，凝血酶原时间延长。停用阿奇霉素3天后，升高的凝血酶原时间恢复正常。在国际标准化比值最初升高后，由于我们的患者不存在影响华法林抗凝效果的任何显著混杂因素，且有大量此类相互作用的报道，表明阿奇霉素与华法林之间的相互作用可能是该患者凝血酶原时间升高的原因。客观因果关系评估显示，该不良事件可能与这些药物的联合使用有关。
与红霉素和克拉霉素不同，阿奇霉素不被认为会抑制细胞色素P450酶系统，被认为是已服用华法林患者的首选大环内酯类药物。然而，先前报道的阿奇霉素与华法林相互作用的病例支持了阿奇霉素确实与华法林相互作用的可能性，尽管确切机制尚不清楚。
阿奇霉素可能与华法林相互作用并增强其低凝血酶原血症效应。这种效应可能在阿奇霉素疗程结束后4 - 8天出现延迟。在服用华法林的患者中使用阿奇霉素时，建议定期监测凝血酶原时间。
