Joss J D, LeBlond R F
Department of Pharmaceutical Care, University of Iowa Health Care, Iowa City 52246, USA.
Ann Pharmacother. 2000 Jun;34(6):729-33. doi: 10.1345/aph.19309.
To report a case of international normalized ratio (INR) elevation resulting from the administration of topical methyl salicylate in a patient whose INR was previously stable while she received warfarin anticoagulation.
A 22-year-old white woman presented with an INR of 12.2 after applying a topical pain-relieving gel to her knees daily for eight days. The potentiation of the warfarin anticoagulation was attributed to the low-dose methyl salicylate contained in the product.
Methyl salicylate is systemically absorbed through the skin in measurable amounts, and may increase warfarin action by affecting vitamin K metabolism or by displacing warfarin from protein-binding sites. While several investigators have reported this interaction with use of high-dose methyl salicylate, this case indicates that a significant interaction can occur with the use of lower topical doses of methyl salicylate as well.
Healthcare providers and patients taking warfarin must be aware of the potential hazard of using topical methyl salicylate in combination with warfarin.
报告一例在接受华法林抗凝治疗期间国际标准化比值（INR）先前稳定的患者，因外用甲基水杨酸酯导致INR升高的病例。
一名22岁白人女性，在连续八天每天在膝盖上涂抹外用止痛凝胶后，INR达到12.2。华法林抗凝作用增强归因于该产品中含有的低剂量甲基水杨酸酯。
甲基水杨酸酯可通过皮肤被大量吸收入血，可能通过影响维生素K代谢或从蛋白质结合位点置换华法林来增强华法林的作用。虽然有几位研究者报告了高剂量甲基水杨酸酯使用时的这种相互作用，但该病例表明，低剂量外用甲基水杨酸酯也可能发生显著的相互作用。
医疗保健人员和服用华法林的患者必须意识到外用甲基水杨酸酯与华法林联合使用的潜在风险。
