Drug & supplement interaction

Lentinan + Ondansetron

Ondansetron brand name: Zofran.

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

Ondansetron falls into 3 drug categories that Lentinan can interact with; the most serious is rated moderate. Laboratory evidence suggests that lentinan might increase the activity of cytochrome P450 1A2 (CYP1A2).

Read the full interaction report
SeverityModerate
LikelihoodPossible
Interactions3
EvidenceD
What do Severity, Likelihood & Evidence mean?
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Interaction report

Lentinan and Ondansetron

These two interact in 3 distinct ways. Each one is explained separately below.

Why Are There 3 Interactions?

Lentinan interacts with whole categories of medication. Ondansetron falls into 3 of those categories, so it can interact with Lentinan in 3 different ways. We’ve listed each one below — your overall risk is driven by the most serious of them (Moderate).

Moderate

CYTOCHROME P450 1A2 (CYP1A2) SUBSTRATES

1 of 3

Why this applies to Ondansetron

Ondansetron falls under CYTOCHROME P450 1A2 (CYP1A2) SUBSTRATES — the group Lentinan interacts with.

Laboratory evidence suggests that lentinan might increase the activity of cytochrome P450 1A2 (CYP1A2). So far, this interaction has not been reported in humans. However, watch for a decrease in the levels of drugs metabolized by CYP1A2 in patients taking lentinan.
Some drugs metabolized by CYP1A2 include amitriptyline (Elavil), haloperidol (Haldol), ondansetron (Zofran), propranolol (Inderal), theophylline (Theo-Dur, others), verapamil (Calan, Isoptin, others), and 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 for shiitake-derived lentinan and your Zofran. Your body uses a liver enzyme called CYP1A2 to help clear ondansetron. Lab and animal studies hint that lentinan may speed up that enzyme. If that happened in people, your body could break down ondansetron a bit faster, leaving slightly less of it around to do its job. Since ondansetron is active as-is (not a prodrug), faster clearance points toward a weaker anti-nausea effect, meaning more breakthrough nausea or vomiting during chemo or after surgery.

The reassuring part: this is only test-tube and animal evidence, and it has never actually been reported in humans. So I wouldn't lose sleep over it. Still, if you plan to use a lentinan supplement, mention it to your pharmacist or oncologist first so they can keep an eye on how well your nausea stays controlled.

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.
Moderate

CYTOCHROME P450 2D6 (CYP2D6) SUBSTRATES

2 of 3

Ondansetron also falls under CYTOCHROME P450 2D6 (CYP2D6) SUBSTRATES.

Laboratory research suggests that lentinan might increase the activity of cytochrome P450 2D6 (CYP2D6). So far, this interaction has not been reported in humans. However, watch for a decrease in the levels of drugs metabolized by CYP2D6 in patients taking lentinan.
Some drugs metabolized by CYP2D6 include tricyclic antidepressants such as imipramine (Tofranil) and amitriptyline (Elavil); antipsychotics such as haloperidol (Haldol), risperidone (Risperdal), and chlorpromazine (Thorazine); beta-blockers such as propranolol (Inderal), metoprolol (Lopressor, Toprol XL), and carvedilol (Coreg); tamoxifen (Nolvadex); and 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 shiitake-derived lentinan and your ondansetron (Zofran). Lab and animal research hints that lentinan might rev up an enzyme called CYP2D6, which is one of the routes your body uses to clear ondansetron. If that enzyme speeds up, your body could break down the ondansetron a little faster, which in theory might leave less of it working. For an anti-nausea drug, that could mean it doesn't control nausea or vomiting quite as well as expected.

I want to be honest about how thin this evidence is: it has only been seen in test tubes and animals, never reported in actual people. So this is more of a 'keep an eye out' note than a red alert. Ondansetron isn't a prodrug, so the concern is reduced effect, not extra side effects. If you're using lentinan during chemo, just mention it to your oncology pharmacist or doctor so they can watch how well your nausea is controlled.

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.
Moderate

CYTOCHROME P450 3A4 (CYP3A4) SUBSTRATES

3 of 3

Ondansetron also falls under CYTOCHROME P450 3A4 (CYP3A4) SUBSTRATES.

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 for Zofran (ondansetron) with lentinan. Your liver uses an enzyme called CYP3A4 to help break ondansetron down. Lab and animal studies hint that lentinan may speed that enzyme up. If that happened in people, your body could clear ondansetron a bit faster, which in theory could make it a little less effective at controlling nausea and vomiting.

The important part: this has only been seen in test-tube and animal research, never confirmed in humans, so I wouldn't lose sleep over it. Ondansetron also has other backup pathways, which softens the concern. If you're using lentinan during chemo and notice your nausea isn't well controlled, mention it to your oncology team or pharmacist before changing anything.

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 Ondansetron one above is among them. If you take anything else, check it against the full list below.

Moderate 813 No known interaction 2,017 (incl. Ondansetron)
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 Ondansetron

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 Ondansetron, 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 Ondansetron

This page covers Lentinan only. If you take other supplements — a multivitamin, a sleep aid, something for joints — the Ondansetron page lists 195 supplements it has a documented interaction with, worst first, each one explained.

The most serious there right now: Activated Charcoal (major), Grapefruit (major), Lithium (major), St. John's Wort (major) and 1,3-dmaa (moderate).

By severity: 4 major · 145 moderate · 46 minor.

From our pharmacist’s overview on the Ondansetron page

“Ondansetron (Zofran) often stands between you and relentless nausea from chemotherapy or surgery, so read this page carefully. Four of the 195 ingredients rate major.”

Reviewed by 2 · Jul 18, 2026

Open the Ondansetron 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 Ondansetron 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 Ondansetron 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
Steady interest

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

29 days ago today
Medication Ondansetron
Steady interest

#2,073 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 Ondansetron

What Is Ondansetron Used For?

Brand name: Zofran

Ondansetron is used to prevent nausea and vomiting in several situations. Oral forms (tablets, orally disintegrating tablets, and oral solution) are approved to prevent nausea and vomiting from highly or moderately emetogenic (nausea-causing) cancer chemotherapy, from radiation therapy to the abdomen or whole body, and from surgery.

Ondansetron injection (given intravenously or intramuscularly in a clinical setting) is approved to prevent nausea and vomiting from emetogenic cancer chemotherapy — including high-dose cisplatin — in adults and children as young as 6 months old, as well as to prevent postoperative nausea and vomiting.

See full Ondansetron 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 Ondansetron, 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 Ondansetron supplement interactions › Every supplement checked against Ondansetron, ranked by severity Ondansetron 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 Ondansetron Together: Common Questions

Can you take Lentinan with Ondansetron?
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 3 interactions listed for Lentinan and Ondansetron?
Ondansetron belongs to more than one drug category, and Lentinan 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 Lentinan and Ondansetron 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 Ondansetron 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.