Drug & supplement interaction

Lentinan + Cobimetinib Fumarate

Cobimetinib Fumarate brand name: Cotellic.

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

Lentinan has a moderate interaction with Cobimetinib Fumarate. Laboratory research suggests that lentinan might increase the activity of cytochrome P450 3A4 (CYP3A4).

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

Lentinan and Cobimetinib Fumarate

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

Moderate

CYTOCHROME P450 3A4 (CYP3A4) SUBSTRATES

Why this applies to Cobimetinib Fumarate

Cobimetinib Fumarate falls under CYTOCHROME P450 3A4 (CYP3A4) SUBSTRATES — the group Lentinan interacts with.

Laboratory research suggests that lentinan might increase the activity of cytochrome P450 3A4 (CYP3A4). So far, this interaction has not been reported in humans. However, watch for a decrease in the levels of drugs metabolized by CYP3A4 in patients taking lentinan.
Some drugs metabolized by CYP3A4 include lovastatin (Mevacor), ketoconazole (Nizoral), itraconazole (Sporanox), fexofenadine (Allegra), triazolam (Halcion), 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 gist: your cobimetinib (Cotellic) is cleared from your body by a liver enzyme called CYP3A4. Lab studies hint that lentinan might rev up that enzyme a bit. If that happened in real life, your body could break down cobimetinib faster, leaving less of it in your blood. The worry there isn't extra side effects, it's the opposite: the drug might not work as well against your melanoma, which is the last thing you want.

Now, the honest part: this is only seen in test-tube and animal research, never confirmed in people, so it's more of a theoretical caution than a proven problem. Still, with a cancer treatment like this, I wouldn't gamble. Please run any lentinan or shiitake supplement past your oncologist or pharmacist before starting it.

Contact Dr. Brian directly if you have additional questions on this interaction
References
  1. Lin Y, Wei Y, Hu X, et al. Evaluation of lentinan effects on cytochrome P450 activity in rats by a cocktail method. Iran J Basic Med Sci. 2019;22(3):296-301.

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

Lentinan Also Interacts With Other Medications

Lentinan has 813 moderate known drug interactions in our database — the Cobimetinib Fumarate one above is one of them. If you take anything else, check it against the full list below.

Moderate 813 No known interaction 2,017 (incl. Cobimetinib Fumarate)
Taking anything else?

Check Another of Your Medications Against Lentinan

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

From our Q&A

Questions About Lentinan or Cobimetinib Fumarate

These are real questions from readers, answered by the pharmacists at HelloPharmacist — written by a person, not generated from a database. Each one covers Lentinan or Cobimetinib Fumarate, 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 Cobimetinib Fumarate

This page covers Lentinan only. If you take other supplements — a multivitamin, a sleep aid, something for joints — the Cobimetinib Fumarate page lists 138 supplements it has a documented interaction with, worst first, each one explained.

The most serious there right now: Activated Charcoal (major), Grapefruit (major), St. John's Wort (major), Acacia Rigidula (moderate) and Adrafinil (moderate).

By severity: 3 major · 94 moderate · 41 minor.

From our pharmacist’s overview on the Cobimetinib Fumarate page

“If you are on cobimetinib (Cotellic) for melanoma, be strict about supplements, because this list carries real weight. The drug is cleared by the liver enzyme CYP3A4, and nearly all 138 flagged ingredients can push its blood level up or down through that pathway.”

Reviewed by 2 · Jul 18, 2026

Open the Cobimetinib Fumarate interaction page

One more smart check

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

We hold 1 real supplement products containing Lentinan, each one broken down to its full ingredient list — and combination products often carry several ingredients besides Lentinan. Your product may carry other ingredients that interact with Cobimetinib Fumarate too, on top of Lentinan — 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 Lentinan and Cobimetinib Fumarate 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 Lentinan
Top half

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

29 days ago today
Medication Cobimetinib Fumarate
Top 25%

#381 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 Lentinan

What is Lentinan?

Lentinan
  • Immune support
  • Used alongside cancer treatment
  • Anti-inflammatory
  • General wellness/tonic
  • Antimicrobial support

Lentinan is a beta-glucan polysaccharide from shiitake mushrooms that is studied mainly as an immune-modulating add-on to cancer chemotherapy, where it is given by injection in a few countries. Evidence for oral supplements is limited, and quality varies widely between products. Talk with your pharmacist or doctor before using it, especially if you have a health condition or are pregnant or breastfeeding.

Read the full Lentinan monograph & all interactions
Medication

About Cobimetinib

What Is Cobimetinib Used For?

Brand name: Cotellic

Cobimetinib is approved for two uses in adults. First, it is used in combination with another drug called vemurafenib to treat melanoma (a type of skin cancer) that cannot be surgically removed or has spread to other parts of the body — but only when the tumor carries a specific genetic change called a BRAF V600E or V600K mutation. A lab test must confirm this mutation before treatment begins.

Second, cobimetinib can be used on its own (as a single agent) to treat adults with histiocytic neoplasms — a rare group of cancers involving immune cells called histiocytes.

See full Cobimetinib drug information
Keep checking

Other Drugs & Lentinan

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

0Major
813Moderate
0Minor
2,016No known interaction
813 Moderate 2,016 No interaction
Moderate

813 interactions

Showing 60 of 813 moderate interactions — see all 813 on the Lentinan page.

No interaction 2,016 drugs checked — show the list

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

Showing the 60 most looked-up of 2,016 medications checked with no known interaction — see the full Lentinan list.

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

Can you take Lentinan with Cobimetinib Fumarate?
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 Lentinan and Cobimetinib Fumarate 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 Cobimetinib Fumarate and Lentinan?

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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.