Drug & supplement interaction

Chokeberry + Fostamatinib

Fostamatinib brand name: Tavalisse.

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

Chokeberry has a moderate interaction with Fostamatinib. Theoretically, chokeberry might increase levels of drugs metabolized by CYP3A4.

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

Chokeberry 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 Chokeberry interacts with.

Theoretically, chokeberry might increase levels of drugs metabolized by CYP3A4.
In vitro research shows that chokeberry inhibits CYP3A4. In humans, there is one case report of a drug interaction with trabectedin, a CYP3A4 substrate, which is hypothesized to have been caused by chokeberry inhibition of CYP3A4.
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 short version: your body uses an enzyme called CYP3A4 to break down fostamatinib's active form (R406). Chokeberry has shown, mostly in lab dishes, that it can slow down that same enzyme. If that happens in real life, fostamatinib could clear more slowly and build up a bit, which may mean stronger effects and a higher chance of side effects like high blood pressure, diarrhea, nausea, or changes in your liver tests.

I want to be honest about how thin the evidence is. This is mostly theoretical, with just one case report involving a different drug, so we don't know it actually matters with chokeberry food amounts. Concentrated supplements are the bigger question. Before adding chokeberry pills, check with your pharmacist or doctor.

Contact Dr. Brian directly if you have additional questions on this interaction
References
  1. Bräunlich M, Christensen H, Johannesen S, Slimestad R, Wangensteen H, Malterud KE, Barsett H. In vitro inhibition of cytochrome P450 3A4 by Aronia melanocarpa constituents. Planta Med. 2013 Jan;79(2):137-41. PubMed
  2. Strippoli S, Lorusso V, Albano A, Guida M. Herbal-drug interaction induced rhabdomyolysis in a liposarcoma patient receiving trabectedin. BMC Complement Altern Med. 2013 Jul 30;13:199. 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

Chokeberry Also Interacts With Other Medications

Chokeberry has 810 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 810 No known interaction 2,020 (incl. Fostamatinib)
Taking anything else?

Check Another of Your Medications Against Chokeberry

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

Everything else you take

See Every Supplement That Interacts With Fostamatinib

This page covers Chokeberry 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 Chokeberry as Part of a Dietary Supplement Product? Check It for Interactions

We hold 493 real supplement products containing Chokeberry, each one broken down to its full ingredient list — and combination products often carry several ingredients besides Chokeberry. Your product may carry other ingredients that interact with Fostamatinib too, on top of Chokeberry — 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 Chokeberry 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 Chokeberry
Top half

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

29 days ago today
Medication Fostamatinib
Steady interest

#1,846 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 Chokeberry

What is Chokeberry?

Chokeberry
  • Antioxidant support
  • Heart and blood vessel health
  • Blood pressure support
  • Blood sugar support
  • Common cold symptoms
  • Anti-inflammatory support

Chokeberry (aronia) is a dark berry rich in antioxidants called polyphenols, and it's widely eaten as juice, jam, and supplements. Early research hints it may support heart health, blood pressure, and blood sugar, but the evidence is still limited and far from proven. It's generally well tolerated as a food, but talk to your pharmacist or doctor before using concentrated supplements.

Read the full Chokeberry 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 & Chokeberry

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

0Major
810Moderate
0Minor
2,019No known interaction
810 Moderate 2,019 No interaction
Moderate

810 interactions

Showing 60 of 810 moderate interactions — see all 810 on the Chokeberry page.

No interaction 2,019 drugs checked — show the list

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

Showing the 60 most looked-up of 2,019 medications checked with no known interaction — see the full Chokeberry list.

See the full Chokeberry 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
Chokeberry 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 Chokeberry and Fostamatinib Together: Common Questions

Can you take Chokeberry 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 Chokeberry 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 Chokeberry?

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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.