Supplements and Immunosuppressants and Transplant Medicines

Safety box: ask the transplant team before adding anything

Medicines that prevent organ rejection or calm the immune system can work within a narrow range, where too little may mean the medicine does not work and too much can be toxic. A 2022 review describes tacrolimus as having "a narrow therapeutic window, dose-dependent toxicity" and large differences between people. [1] This page is information only. Do not start, stop or change any herb, supplement or prescribed medicine on your own; ask the transplant team, prescriber or pharmacist. For collapse, seizure or trouble breathing, call 911.

The question

Which herbs and supplements are documented to change the levels or effects of immunosuppressants (cyclosporine, tacrolimus and related medicines), and which are only theoretical? This page keeps those labels separate.

St. John's wort (Hypericum perforatum): the best-documented concern

GBIF lists Hypericum perforatum as the accepted name. [2]

• NCCIH lists cyclosporine, "which prevents the body from rejecting transplanted organs," among the medicines St. John's wort can affect. [3]
• MedlinePlus names St. John's wort among nonprescription or herbal products that may interact with cyclosporine. [4]
• A 2009 review of clinical observations lists reduced blood cyclosporine levels as a well-documented interaction, "as suggested by multiple case reports as well as by clinical trials." [5]
• The 2022 tacrolimus review says CYP3A4 inducers such as St. John's wort "may result in a lack of therapeutic effect by reducing the drug concentration." [1]

Label: documented (case reports, trials). Details: St. John's Wort Interactions.

Grapefruit and related fruit

FDA names some organ-transplant rejection drugs among medicines grapefruit juice can interact with. [6] MedlinePlus tells people taking cyclosporine to avoid grapefruit juice and grapefruit. [4] The tacrolimus review reports that CYP3A4 inhibitors such as grapefruit, pomelo, clementine, pomegranate, ginger and turmeric can raise tacrolimus levels. [1] Label: documented for grapefruit; the other items come from a literature review and are better described as reported or preliminary. See Grapefruit and Medicine Interactions.

Herbs described as controversial or uncertain

• The tacrolimus review calls the use of Panax ginseng, green tea, Schisandra sphenanthera and melatonin during tacrolimus treatment "highly controversial." [1]
• Echinacea: NCCIH says there are "theoretical reasons to suspect" an interaction with immunosuppressants, and conflicting evidence about interactions with some drugs handled by the liver. [7] Label: theoretical.
• Ashwagandha (Withania somnifera): NCCIH says there is evidence it might interact with medicines that decrease the immune system response. [8]

"Immune support" products

Products marketed for "immune support" deserve extra caution in this group. We did not find, in the sources read, a trial showing such products are safe in transplant recipients. A review of pediatric transplant recipients says several herbal products can alter immune status or immunosuppressant levels or cause kidney or liver toxicity, and should be avoided in that group. [9] Proper evidence not found for adults on this exact question; we searched PubMed and NCCIH pages.

What a reader can do

• Give the transplant team and pharmacist a full list, including teas, tinctures and gummies. The tacrolimus review says every herb or supplement should be reported to the physician. [1]
• Ask before starting, and before stopping, anything.
• Check the label for St. John's wort in "mood" or "sleep" blends, and see Product Quality and Contamination.
• More: How Interactions Work, Immunodeficiency, Autoimmune Conditions and Immunosuppression and Echinacea.