Interaction Between Warfarin and Panax ginseng in Ischemic Stroke Patients
Today, the combined use of Oriental herbal medicines and Western biomedical medicines has been a prevalent yet controversial practice. Case reports and healthy volunteer trials have had conflicting results on the effect Panax ginseng has on warfarin's pharmacologic action, some reporting a reductive and others a potentiating influence.
This study investigated the interaction between warfarin and P. ginseng by observing the prothrombin time (PT) and the international normalized ratio (INR) in ischemic stroke patients who did not have a history of taking warfarin.
Randomized, open-label, controlled study.
Twenty-five (25) patients newly diagnosed with ischemic stroke by brain computed tomography or magnetic resonance imaging in the Korean Medical Hospital, Kyung Hee University (Seoul, Republic of Korea).
Ischemic stroke patients were randomized into 2 groups: the ginseng group (n = 12), given both P. ginseng and warfarin, and the control group (n = 13), given only warfarin, both for 2 weeks. The warfarin dose was restricted to 2 mg in the first week and 5 mg in the second week.
The peak values and the international normalized ratio (INR) and prothrombin time (PT) areas under the curve (AUC) in both groups significantly increased compared to those at baseline. However, there was no statistically significant difference in peak values and INR and PT AUC between groups in both the first and second weeks.
This study suggests that coadministration of P. ginseng and warfarin in ischemic stroke patients does not influence the pharmacologic action of warfarin.
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- "In one report, an herbal formula combination of Tribulus terrestris, Avena sativa, and Panax ginseng was reported to result in a sudden increase in the INR of patients who took warfarin for aortic valve replacement or atrial fibrillation . However, another randomized controlled trial study reported that Panax ginseng did not have any effect on INR . Whether or not herbal formulas influence INR is still con- troversial. "
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ABSTRACT: Warfarin is a common anticoagulant agent for cardiovascular diseases, and it is known to interact with several foods and drugs. Several studies report an interaction between warfarin and herbal medicines; however, the influence of herbal medicines on the international normalized ratio (INR) is still controversial. We investigated the influence of herbal formulas on INR of patients taking warfarin. We searched electronic medical records of inpatients for INR results. Then, we compared the changes in INR and any adverse events between the group taking herbal formulas and warfarin (herbal group) and another group taking warfarin only (nonherbal group). Eighty-six patients were included; 45 patients were assigned to the herbal group and 41 patients to the nonherbal group. The herbal group had taken the same dose of warfarin for a longer period. The nonherbal group had a slightly higher mean INR value than the herbal group. The ratio of INR less than 2 and greater than 3, the ratio of INR that increased or decreased by one or more compared to the initial INR, and the ratio of adverse events were not significantly different between the two groups. It is suggested that use of herbal formulas may not influence INR value.
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- "Evidence from three RCTs for co-administration of ginseng and warfarin was inconclusive (grade: insufficient) [68-70]. "
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The objective of this systematic review was to examine the benefits, harms and pharmacokinetic interactions arising from the co-administration of commonly used dietary supplements with cardiovascular drugs. Many patients on cardiovascular drugs take dietary supplements for presumed benefits and may be at risk for adverse supplement-drug interactions.
The Allied and Complementary Medicine Database, the Cochrane Library, EMBASE, International Bibliographic Information on Dietary Supplements and MEDLINE were searched from the inception of the review to October 2011. Grey literature was also reviewed.
Two reviewers independently screened records to identify studies comparing a supplement plus cardiovascular drug(s) with the drug(s) alone. Reviewers extracted data using standardized forms, assessed the study risk of bias, graded the strength of evidence and reported applicability.
Evidence was obtained from 65 randomized clinical trials, 2 controlled clinical trials and 1 observational study. With only a few small studies available per supplement, evidence was insufficient for all predefined gradable clinical efficacy and harms outcomes, such as mortality and serious adverse events. One long-term pragmatic trial showed no benefit from co-administering vitamin E with aspirin on a composite cardiovascular outcome. Evidence for most intermediate outcomes was insufficient or of low strength, suggesting no effect. Incremental benefits were noted for triglyceridemia with omega-3 fatty acid added to statins; and there was an improvement in levels of high-density lipoprotein cholesterol with garlic supplementation when people also consumed nitrates
Evidence of low-strength indicates benefits of omega-3 fatty acids (plus statin, or calcium channel blockers and antiplatelets) and garlic (plus nitrates or warfarin) on triglycerides and HDL-C, respectively. Safety concerns, however, persist.
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- "In contrast, Jiang et al.15 showed that co-administration of warfarin with ginseng did not affect the pharmacokinetics or pharmacodynamics of either S-warfarin or R-warfarin in healthy subjects in 2004. Recently, Lee, et al.16 also found that co-administration of panax ginseng and warfarin in ischemic stroke patients does not influence the pharmacologic action of warfarin. Later study by Jiang, et al.17 demonstrated that Asian ginseng could actually modestly increase the clearance of warfarin and decrease its effectiveness. "
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ABSTRACT: A 71-year-old man was stable on warfarin (2.25 mg daily) therapy with an international normalized ratio (INR) of 1.8-2.2 after a heart valve replacement surgery. Recently, he consumed the liquid-like herbal product called shengmai-yin (10 mL daily) against medical advice. Seven days after the daily consumption of shengmai-yin, he was admitted to the intensive care unit because of consciousness disturbance [Glasgow Coma Scale (GCS) score 7] with an INR of 5.08. Head computed topography revealed intracerebral hematoma in the left temporoparietal region. Both warfarin therapy and the herbal product were withdrawn. At the same time, therapy with intravenous vitamin K1 40 mg was started. On the second day of admission, craniectomy was performed to remove the intacerebral hematoma under general anesthesia. He remained confused and restless for 2 days, but then showed progressive recovery in the consciousness level as well as motor and verbal functions. Shengmai-yin contains herbal ingredients that can interact with warfarin. The Drug Interaction Probability Scale (DIPS) indicated that warfarin and shengmai-yin were highly probable causes of intracerebral hematoma. Patients on warfarin therapy should be discouraged from taking herbal medicines, especially preparations that are already known to have antiplatelet and antithrombotic effects.
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