No increase in bleeding risk with traditional Chinese herbs
The traditional medicinal herbs ginseng, dong-quai, and turmeric do not appear to affect platelet aggregation and increase bleeding risk when used alone or together with aspirin, despite the belief that these herbs have “blood-activating” properties in traditional medicine theory, a recent study shows.
“With the level 1 evidence provided by this randomized clinical trial, we hope that it serves to dispel some myths on this issue and enable Western Medicine physicians to more confidently advise their patients on the safety of taking turmeric, dong-quai, or ginseng with respect to bleeding risk,” said the researchers led by Dr Linn Yeh Ching of Singapore General Hospital.
The double-blind crossover study involved 75 healthy volunteers (median age 31 years) who received one of the herbal supplements (n=25 for each group) containing turmeric (Curcuma longa), dong-quai (Angelica sinensis), or ginseng (Panax ginseng), all 500 mg, to undergo three phases during the study. The first phase entailed participants taking the herbal supplement alone, followed by randomization to herbal supplement or placebo in combination with aspirin in phase 2, and subsequently a crossover of the two treatments in phase 3. Each phase ran for 3 weeks with a washout period of 2 weeks between phases. [Phytomedicine 2017;32:88-96]
Taking the herbal products alone did not suppress platelet aggregation induced by the agonists tested, including adenosine diphosphate (ADP), arachidonic acid (AA), epinephrine, collagen, and ristocetin in a majority of the participants, except for a few cases in each herbal group.
The few cases affected were five participants taking turmeric, two participants taking dong-quai, and one participant taking ginseng who had reduced AA-induced platelet aggregation compared with baseline. Although the reduction in the five cases taking turmeric drove the decline in overall platelet aggregation to AA from 100 percent at baseline to a median of 91 percent (p=0.012), no bleeding events were reported.
Similarly with dong-quai, no significant bleeding events were observed except for reports of heavier menses in two other subjects, which the researchers suggested to be attributed to the oestrogenic properties of the herb.
The ginseng group also showed reduced platelet aggregation induced by ADP compared with baseline (90 percent vs 83 percent; p=0.044), but all readings were within the normal range and hence, not of clinical significance, according to the researchers.
“Although some of the paired comparisons of herbs alone vs baseline showed statistically significant difference, these were of small magnitude that should not be interpreted as clinically significant,” said Linn and co-authors. “Taken as a whole, [this] suggests that the effects of the three herbs on haemostatic function, if any, are sporadic and limited in extent, and are without any clinical impact.”
There were no effects on thrombin generation and platelet function, as indicated by PT/APTT* ratio, with all three herbal products when used either alone or together with aspirin. The addition of herbal supplement to aspirin also did not further increase the suppression of platelet aggregation nor risk of bleeding with aspirin alone.
“Drug databases should consider revising their current blanket statements advising against the use of these three herbs with aspirins and other antiplatelet agents,” urged Linn and co-authors.
“Patients with additional disorders that may cause platelet dysfunction or clotting defect, or patients with hepatic or renal impairment that may affect drug and herb metabolism or excretion will still have to exercise caution when using such combinations,” they advised.
Nonetheless, the findings may not necessarily contradict the known “blood-activating” properties of the herbs, to which the researchers said, “there may be other haemorrheological mechanisms such as effect on blood viscosity or vasodilatory effects resulting in improvement in microcirculation, which are not measured in this study.” [Lishizhen Med Materia Medica Res 2006;17:2082-2083]