Review Article
Updates on the Clinical Evidenced Herb-Warfarin Interactions
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Notes: A: in patient-based studies, warfarin must been taken at a stabilized dose before initiation of the interacting herbs. In addition, the potentially interacting herbs should be consumed long enough in usual doses to attain a substantial plasma level. For volunteer-based studies, subjects had to receive warfarin, both alone and with the interacting herbs, for similar periods. B: in patient-based articles, the coagulation variable should be out of therapeutic range, whereas for volunteer studies, a change of at least 20% was required in coagulation parameters. For conclusion of “no interaction,” the absence of a statistically significant change in coagulation variables was required. C: factors such as diet, other medications, or certain medical conditions, especially liver diseases, should be declared to be ruled out as possible causes of the outcome. D: other objective evidences refer to changes in plasma level of warfarin or level of vitamin K dependent clotting factors (II, VII, IX, or X). E: the alterations in the dose of the coadministrated interacting herbs correlated with subsequent changes in warfarin coagulation variables, inferring a dose-response relationship. F: the interacting herb should be administered simultaneously with warfarin in two or more separate courses, with similar results for each course. G: similar outcome should be found for the patient cousing the interacting herb with warfarin at a time prior to that reported. |