Drug & supplement interaction

Grape + Selumetinib Sulfate

Selumetinib Sulfate brand name: Koselugo.

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

Selumetinib Sulfate falls into 2 drug categories that Grape can interact with; the most serious is rated moderate. It is unclear if grape seed extract inhibits or induces CYP3A4; research is conflicting.

Read the full interaction report
SeverityModerate
LikelihoodPossible
Interactions2
EvidenceD
What do Severity, Likelihood & Evidence mean?
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Interaction report

Grape and Selumetinib Sulfate

These two interact in 2 distinct ways. Each one is explained separately below.

Why Are There 2 Interactions?

Grape interacts with whole categories of medication. Selumetinib Sulfate falls into 2 of those categories, so it can interact with Grape in 2 different ways. We’ve listed each one below — your overall risk is driven by the most serious of them (Moderate).

Moderate

CYTOCHROME P450 3A4 (CYP3A4) SUBSTRATES

1 of 2

Why this applies to Selumetinib Sulfate

Selumetinib Sulfate falls under CYTOCHROME P450 3A4 (CYP3A4) SUBSTRATES — the group Grape interacts with.

It is unclear if grape seed extract inhibits or induces CYP3A4; research is conflicting.
In vitro evidence suggests that grape seed extract might inhibit CYP3A4 enzymes. However, evidence from animal research shows that grape seed extract may induce CYP3A4 in the liver. So far, these interactions have not been reported in humans.
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 grape seed extract and Koselugo (selumetinib). Selumetinib is cleared from your body mainly by a liver enzyme called CYP3A4, and it's an active drug, not a prodrug that needs switching on. So if something slows that enzyme down, selumetinib can build up and bring more side effects like nausea, diarrhea, mouth sores, rash, or tiredness. If something speeds the enzyme up instead, the drug may clear too fast and work less well.

The honest truth is the lab and animal studies disagree about which direction grape seed extract pushes, and this has never actually been reported in people. Eating grapes is not a concern, but concentrated supplements are a bigger unknown. Please check with your child's oncology team or pharmacist before adding one.

Contact Dr. Brian directly if you have additional questions on this interaction
References
  1. Nishikawa, M., Ariyoshi, N., Kotani, A., Ishii, I., Nakamura, H., Nakasa, H., Ida, M., Nakamura, H., Kimura, N., Kimura, M., Hasegawa, A., Kusu, F., Ohmori, S., Nakazawa, K., and Kitada, M. Effects of continuous ingestion of green tea or grape seed extra
  2. Etheridge, A. S., Black, S. R., Patel, P. R., So, J., and Mathews, J. M. An in vitro evaluation of cytochrome P450 inhibition and P-glycoprotein interaction with goldenseal, Ginkgo biloba, grape seed, milk thistle, and ginseng extracts and their constitu
Moderate

ANTICOAGULANT/ANTIPLATELET DRUGS

2 of 2

Selumetinib Sulfate also falls under ANTICOAGULANT/ANTIPLATELET DRUGS.

Theoretically, grape extracts may have antiplatelet effects and may increase the risk of bleeding if used with anticoagulant or antiplatelet drugs.
In vitro evidence suggests that grape extracts might decrease platelet aggregation.
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 honest picture for your child taking Koselugo (selumetinib) alongside a grape supplement. The interaction we have on file is really about grape's possible effect on platelets, the tiny cells that help blood clot. In lab studies, concentrated grape extracts seemed to make platelets a little less sticky, which could theoretically add to any bleeding risk. This is grouped with blood thinners, so the worry is a slightly higher chance of bruising or bleeding if the two stack up.

I want to be clear: this is theoretical, based only on test-tube data, and eating grapes or drinking grape juice is very unlikely to matter. Concentrated grape seed extract is the bigger question. Since selumetinib already needs careful monitoring, please run any grape supplement past your pharmacist or oncology team before starting it.

Contact Dr. Brian directly if you have additional questions on this interaction
References
  1. de Lange, D. W., Scholman, W. L., Kraaijenhagen, R. J., Akkerman, J. W., and van de Wiel, A. Alcohol and polyphenolic grape extract inhibit platelet adhesion in flowing blood. Eur.J Clin.Invest 2004;34(12):818-824. PubMed
  2. de Lange, D. W., Verhoef, S., Gorter, G., Kraaijenhagen, R. J., van de Wiel, A., and Akkerman, J. W. Polyphenolic grape extract inhibits platelet activation through PECAM-1: an explanation for the French paradox. Alcohol Clin.Exp.Res 2007;31(8):1308-1314 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

Grape Also Interacts With Other Medications

Grape has 867 moderate, 42 minor known drug interactions in our database — the Selumetinib Sulfate one above is among them. If you take anything else, check it against the full list below.

Moderate 867 Minor 42 No known interaction 1,921 (incl. Selumetinib Sulfate)
Taking anything else?

Check Another of Your Medications Against Grape

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

From our Q&A

Questions About Grape or Selumetinib Sulfate

These are real questions from readers, answered by the pharmacists at HelloPharmacist — written by a person, not generated from a database. Each one covers Grape or Selumetinib Sulfate, not necessarily both, but if one is close to what you were about to ask it will usually go further than a database entry can:

Not quite your question? Ask our pharmacists directly — it is free, there is no account required, and answers usually come back within 24 hours.

Everything else you take

See Every Supplement That Interacts With Selumetinib Sulfate

This page covers Grape only. If you take other supplements — a multivitamin, a sleep aid, something for joints — the Selumetinib Sulfate page lists 282 supplements it has a documented interaction with, worst first, each one explained.

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

By severity: 5 major · 236 moderate · 41 minor.

Open the Selumetinib Sulfate interaction page

One more smart check

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

We hold 8,053 real supplement products containing Grape, each one broken down to its full ingredient list — and combination products often carry several ingredients besides Grape. Your product may carry other ingredients that interact with Selumetinib Sulfate too, on top of Grape — 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 Grape and Selumetinib Sulfate 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 Grape
Top 5%

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

29 days ago today
Medication Selumetinib Sulfate
Steady interest

#2,173 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 Grape

What is Grape?

Grape
  • Antioxidant support
  • Heart and circulation health
  • Vein problems (such as varicose veins)
  • Eye health
  • General anti-inflammatory support

Grapes and grape products like grape seed extract contain antioxidant compounds such as resveratrol and proanthocyanidins that may support heart and blood vessel health. While the food is healthy and generally safe, the supplement evidence for treating specific conditions is mostly limited or preliminary. Talk with your pharmacist or doctor before starting a grape supplement.

Read the full Grape monograph & all interactions
Medication

About Selumetinib

What Is Selumetinib Used For?

Brand name: Koselugo

Koselugo (selumetinib) is approved for adults and children 1 year of age and older who have neurofibromatosis type 1 (NF1) — a genetic condition that causes tumors to grow on nerve tissue — when they also have symptomatic, inoperable plexiform neurofibromas (large, deep nerve tumors that cannot be surgically removed and are causing problems).

Both the Koselugo capsule and Koselugo oral granule formulations are approved for this use. The oral granule form is intended for patients who have difficulty swallowing whole capsules.

See full Selumetinib drug information
Keep checking

Other Drugs & Grape

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

0Major
867Moderate
42Minor
1,920No known interaction
867 Moderate 42 Minor 1,920 No interaction
Moderate

867 interactions

Showing 60 of 867 moderate interactions — see all 867 on the Grape page.

Minor

42 interactions

No interaction 1,920 drugs checked — show the list

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

Showing the 60 most looked-up of 1,920 medications checked with no known interaction — see the full Grape list.

See the full Grape interactions page
See every supplement checked against Selumetinib Sulfate, 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
Grape monograph › Uses, safety, and every drug interaction in one place Selumetinib Sulfate supplement interactions › Every supplement checked against Selumetinib Sulfate, ranked by severity Selumetinib 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 Grape and Selumetinib Sulfate Together: Common Questions

Can you take Grape with Selumetinib Sulfate?
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.
Why are there 2 interactions listed for Grape and Selumetinib Sulfate?
Selumetinib Sulfate belongs to more than one drug category, and Grape interacts with each of those categories a little differently. We list every one so nothing is missed — your overall risk is driven by the most serious of them.
How serious is the Grape and Selumetinib Sulfate 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 Selumetinib Sulfate and Grape?

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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.