Potential Unsafe Drug Interactions With Echinacea

What are the potential unsafe interactions between echinacea and medications used to treat cancer, HIV, or respiratory infections?

Concerns about echinacea's potential interactions with certain pharmaceutical drugs are mostly based on evidence from lab tests:

Because laboratory research indicates echinacea inhibits CYP3A4, echinacea could also increase levels of the following drugs (and increase their adverse effects):(15)

Results of an animal study suggest that taking Echinacea purpurea with melatonin supplements may be harmful.(16)

Clinical Studies

⇑ back to top

There was one case reporting a possible interaction between echinacea and the chemotherapy drug etoposide. Since the lung cancer patient was also taking vitamin B12, vitamin B17, vitamin C, vitamin D, and vitamin E the doctors could not be sure effects were caused by echinacea.(16)

Despite cautions raised by lab tests, clinical studies have shown little cause for concern. Results of recent clinical studies suggest Echinacea purpurea supplements do not interfere with effectiveness of drugs metabolized by the CYP3A and CyP2D6 families of enzymes.(16)

Drugs tested included:(16)

Does Echinacea Interact with Warfarin?

⇑ back to top

Echinacea doesn't appear to harmfully interfere with this common blood thinner. A randomized clinical trial on 12 healthy men determined that those who were pre-treated with echinacea followed by a single dose of warfarin did reduce blood levels of the drug. However, this did not have any significant impact on the drug's effects.(24)

Disclaimer: This website is not intended to replace professional consultation, diagnosis, or treatment by a licensed physician. If you require any medical related advice, contact your physician promptly. Information presented on this website is exclusively of a general reference nature. Do not disregard medical advice or delay treatment as a result of accessing information at this site.
A drug used to treat anxiety disorders.(22)
Drugs used to treat high blood pressure and other cardiovascular related conditions.(22)
Drugs used to treat or prevent viral infections.(22)
Also known as laetrile, a compound found in apricot kernels.(16)
A mix of Echinacea purpurea and E. angustifolia.(16)