Drug & supplement interaction

False Unicorn + Fostamatinib

Fostamatinib brand name: Tavalisse.

Moderate Interaction
Medically reviewed by · Updated September 2026
The bottom line Moderate

False Unicorn has a moderate interaction with Fostamatinib. In vitro, false unicorn extract inhibits cytochrome P450 3A4 (CYP3A4) activity.

Read the full interaction report
SeverityModerate
LikelihoodPossible
EvidenceD
What do Severity, Likelihood & Evidence mean?
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Interaction report

False Unicorn and Fostamatinib

Here is the interaction we found between these two, with the evidence behind it.

Moderate

CYTOCHROME P450 3A4 (CYP3A4) SUBSTRATES

Why this applies to Fostamatinib

Fostamatinib falls under CYTOCHROME P450 3A4 (CYP3A4) SUBSTRATES — the group False Unicorn interacts with.

In vitro, false unicorn extract inhibits cytochrome P450 3A4 (CYP3A4) activity. Theoretically, false unicorn might increase the levels of CYP3A4 substrates. Drugs that might be affected include some calcium channel blockers (diltiazem, nicardipine, verapamil), chemotherapeutic agents (etoposide, paclitaxel, vinblastine, vincristine, vindesine), antifungals (ketoconazole, itraconazole), glucocorticoids, cisapride (Propulsid), alfentanil (Alfenta), fentanyl (Sublimaze), losartan (Cozaar), fluoxetine (Prozac), midazolam (Versed), omeprazole (Prilosec), ondansetron (Zofran), propranolol (Inderal), fexofenadine (Allegra), and numerous others.
Severity Moderate Likelihood Possible Evidence D

Interaction has been documented in animal or in lab research, or the interaction has been documented in humans but is limited to case reports or conflicting clinical research exists.

Dr. Brian Staiger, PharmD, BCPS
Dr. Brian Staiger explains PharmD, Clinical Pharmacist

Here's the situation with these two. Fostamatinib (Tavalisse) is itself turned into its active form, but that active piece is then broken down partly by a liver enzyme called CYP3A4. False Unicorn, at least in test-tube studies, appears to slow that same enzyme down. If it does that in the body too, more of the drug could hang around, which might mean stronger effects and a higher chance of side effects like high blood pressure, diarrhea, nausea, dizziness, or liver enzyme changes.

I want to be honest about the evidence though: this is based on lab work, not real people, so it's theoretical right now. Still, since both can stress the liver and raise blood pressure, I'd run it past your pharmacist or doctor before combining them rather than guessing.

Contact Dr. Brian directly if you have additional questions on this interaction
References
  1. Ho SH, Singh M, Holloway AC, Crankshaw DJ. The effects of commercial preparations of herbal supplements commonly used by women on the biotransformation of fluorogenic substrates by human cytochromes P450. Phytother Res. 2011;25(7):983-9. PubMed

What These Ratings Mean

Every interaction above is graded three ways — here’s the key to each label.

Severity how clinically significant the interaction is
Major

Clinically significant. Avoid the combination, or use only under close professional supervision.

Moderate

Usually worth avoiding or managing — may need monitoring, a dose change, or timing apart.

Minor

Generally not serious. Be aware of it and mention it to your pharmacist.

Likelihood how strong the evidence is that the interaction actually happens in people
  • LikelyWell-controlled human studies have demonstrated the likely existence of this interaction.
  • ProbableInteraction has not been documented in well-controlled studies, however, the interaction has been demonstrated in some small human studies or in controlled animal studies in conjunction with multiple case reports.
  • PossibleInteraction has been documented in animal or in lab research, or the interaction has been documented in humans but is limited to case reports or conflicting clinical research exists.
  • UnlikelyInteraction has been demonstrated in animal or in lab research but has been shown not to occur in humans.
Evidence the quality of the studies behind the rating (graded A–D)
  • AHigh-quality meta-analysis (quantitative systematic review).
  • BCase-control study.
  • CConsensus.
  • DAnecdotal evidence.

These ratings are for information only. Never start, stop, or otherwise change your therapy before speaking with your provider.

Keep it in perspective

False Unicorn Also Interacts With Other Medications

False Unicorn has 739 moderate known drug interactions in our database — the Fostamatinib one above is one of them. If you take anything else, check it against the full list below.

Moderate 739 No known interaction 2,091 (incl. Fostamatinib)
Taking anything else?

Check Another of Your Medications Against False Unicorn

Covers the 2,830 medications we’ve checked against False Unicorn. Pick one to open its full report.

Everything else you take

See Every Supplement That Interacts With Fostamatinib

This page covers False Unicorn only. If you take other supplements — a multivitamin, a sleep aid, something for joints — the Fostamatinib page lists 209 supplements it has a documented interaction with, worst first, each one explained.

The most serious there right now: Activated Charcoal (major), Beer (major), Grapefruit (major), Siberian Cocklebur (major) and St. John's Wort (major).

By severity: 6 major · 167 moderate · 36 minor.

From our pharmacist’s overview on the Fostamatinib page

“I would treat the supplement list for fostamatinib (Tavalisse), a medicine that raises platelet counts in chronic immune thrombocytopenia, with real care. Most of what shows up here involves CYP3A4, the liver enzyme that clears fostamatinib, so grapefruit can drive its blood level up while St.”

Reviewed by 2 · Jul 18, 2026

Open the Fostamatinib interaction page

One more smart check

Taking False Unicorn as Part of a Dietary Supplement Product? Check It for Interactions

We hold 32 real supplement products containing False Unicorn, each one broken down to its full ingredient list — and combination products often carry several ingredients besides False Unicorn. Your product may carry other ingredients that interact with Fostamatinib too, on top of False Unicorn — and those would not show on this page. Find your product and we’ll check every ingredient on its label:

How much people look this up

Where False Unicorn and Fostamatinib Sit Against Everything Else

Out of every supplement and medication people look up on HelloPharmacist, here is where these two land this week — and which way each has been moving.

Supplement False Unicorn
Top half

#459 of 1,452 supplements looked up here in the last 7 days

29 days ago today
Medication Fostamatinib
Steady interest

#1,853 of 2,830 medications looked up here in the last 7 days

29 days ago today

Position among everything looked up on this site, not a measure of how commonly either one is used or how important it is. A supplement can climb this list because of a news story. It counts every request to the page, automated ones included, and nothing here identifies anyone.

Supplement

About False Unicorn

What is False Unicorn?

False Unicorn
  • Menstrual cramps
  • Menopausal symptoms
  • Female infertility support
  • Irregular periods
  • Digestive complaints

False Unicorn is a North American plant whose root has long been used in traditional medicine for women's reproductive and menstrual concerns. There is very little reliable human research to show it actually works, and safety has not been well studied, so it should be used with caution and never during pregnancy. Talk to your pharmacist or doctor before trying it.

Read the full False Unicorn monograph & all interactions
Medication

About Fostamatinib

What Is Fostamatinib Used For?

Brand name: Tavalisse

Tavalisse (fostamatinib) is used to treat thrombocytopenia — dangerously low platelet counts — in adults with chronic immune thrombocytopenia (ITP). It is specifically for people whose platelet counts have not improved enough with at least one earlier ITP treatment.

The goal is to raise platelet counts high enough to reduce the risk of serious bleeding. If platelet counts do not respond sufficiently after 12 weeks, the medication is typically stopped.

See full Fostamatinib drug information
Keep checking

Other Drugs & False Unicorn

Browse every other medication we’ve checked against False Unicorn — both the ones with a known interaction and the ones without. Select any drug for the full detail.

0Major
739Moderate
0Minor
2,090No known interaction
739 Moderate 2,090 No interaction
Moderate

739 interactions

Showing 60 of 739 moderate interactions — see all 739 on the False Unicorn page.

No interaction 2,090 drugs checked — show the list

We also checked False Unicorn against these medications and found no known interaction in our sources. Open any page to confirm.

Showing the 60 most looked-up of 2,090 medications checked with no known interaction — see the full False Unicorn list.

See the full False Unicorn interactions page
See every supplement checked against Fostamatinib, ranked by severity
Sources

Sources & How We Checked

Interaction details are evidence-graded and sourced from the Natural Medicines database. The medication overview comes from MedlinePlus.

Content is written and reviewed by licensed HelloPharmacist pharmacists. See our data sources and editorial standards for how this information is built and checked.

Parts of this content are provided by the Therapeutic Research Center, LLC.

DISCLAIMER: Currently this does not check for drug-drug interactions. This is not an all-inclusive comprehensive list of potential interactions and is for informational purposes only. Not all interactions are known or well-reported in the scientific literature, and new interactions are continually being reported. Input is needed from a qualified healthcare provider including a pharmacist before starting any therapy. Application of clinical judgment is necessary.

© 2021 Therapeutic Research Center, LLC

Keep exploring
False Unicorn monograph › Uses, safety, and every drug interaction in one place Fostamatinib supplement interactions › Every supplement checked against Fostamatinib, ranked by severity Fostamatinib drug information › The full plain-English guide to this medication Supplement interaction checker › Check any supplement or product against your medications Browse medications A–Z › Every drug we've checked against herbs & supplements Ask a pharmacist › Free, personal answer from our licensed team
Pharmacist Counseling Corner

Taking False Unicorn and Fostamatinib Together: Common Questions

Can you take False Unicorn with Fostamatinib?
There is a moderate interaction, so it may be acceptable with monitoring or timing changes — but check with your pharmacist first. Read the full details on this page and confirm with your pharmacist before combining them.
How serious is the False Unicorn and Fostamatinib interaction?
We rate it Moderate. This combination may require monitoring, a dose adjustment, or separating the times you take each one. Consult your pharmacist before using them together.

Written and reviewed by the HelloPharmacist editorial staff. Our editorial policy

Still Have a Question About Fostamatinib and False Unicorn?

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This information is for education only and is not a substitute for professional medical advice. Always check with your pharmacist or doctor before starting, stopping, or combining supplements and medications.