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Rhodiola does not appear to interact with other medications such as warfarin
(Coumadin) and theophylline, as many CAM treatments for depression do, and can be
of value in patients who take multiple drugs. However, Brown and Gerbarg caution that
in some people doses above 600 mg per day of rhodiola can affect platelet aggregation.
Thus, when rhodiola is used with anti-coagulants, bleeding and clotting times should be
tested and doses adjusted as needed.
Brown et al. caution that people should restrict their consumption of caffeine while on
rhodiola, since the stimulant effect can be additive. The Natural Standard cautions of a
broader risk of additive effects, but the clinical data are not available to demonstrate a
significant risk at this point. Brown et al. also caution that, although no unwanted
pregnancies have been reported, rhodiola may impair the effectiveness of birth control
pills and may restore or “normalize” the menstrual cycle.
The Natural Standard warns that rhodiola may lower blood sugar levels and cautions
that persons with diabetes or taking blood sugar lowering medications should monitor
and adjust dosages accordingly. Brown and Gerbarg observe minimal hypoglycemic
effects and suggest monitoring for people who are insulin dependent or unstable
diabetics.
Rhodiola may augment the effects of antianxiety, antibiotic, antidepressant, anticancer,
antioxidant, exercise performance-enhancing and cognitive-enhancing treatments.
Rhodiola may also normalize thyroid function and reduce the necessary dose of
synthetic thyroid replacement medication. It can further enhance the effects of other
treatments for erectile dysfunction. In animal studies, rhodiola showed no significant
effects on the metabolism or serum levels of theophylline or warfarin or on the
anticoagulant activity of warfarin, indicating that it is not likely to significantly interfere
with medications metabolized by the CYP450 enzyme systems.^15 There are no reported
cases of bleeding attributable to rhodiola.
Brown and Gerbarg caution that these are concerns about potential rhodiola
interactions with drugs are mostly theoretical and have not been documented to occur