Drug & supplement interaction

Passion Flower + Irinotecan

Irinotecan brand names: Camptosar, Onivyde.

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

Irinotecan falls into 2 drug categories that Passion Flower can interact with; the most serious is rated minor. Theoretically, passion flower might reduce the bioavailability of OATP2B1 and OATP1A2 substrates.

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

Passion Flower and Irinotecan

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

Why Are There 2 Interactions?

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

Minor

ORGANIC ANION-TRANSPORTING POLYPEPTIDE SUBSTRATES (OATP)

1 of 2

Why this applies to Irinotecan

Irinotecan falls under ORGANIC ANION-TRANSPORTING POLYPEPTIDE SUBSTRATES (OATP) — the group Passion Flower interacts with.

Theoretically, passion flower might reduce the bioavailability of OATP2B1 and OATP1A2 substrates.
In vitro research shows that the passion flower constituents apigenin and vitexin inhibit OATP2B1 and OATP1A2. This inhibition may be dose-dependent. One specific high-flavonoid passion flower extract (Valverde) seems to inhibit OATP2B1 and OATP1A2, while another extract with a lower flavonoid concentration (Arkocaps) shows less potent inhibition. OATPs are responsible for the uptake of drugs and other compounds into the body; however, the specific activities of OATP2B1 and OATP1A2 are not well characterized.
Severity Minor 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 irinotecan (Camptosar). Passion flower contains plant compounds like apigenin and vitexin that, in lab dishes, can block certain uptake transporters called OATPs. These transporters help move some drugs into cells. In theory, if passion flower slows that uptake, it could nudge how much irinotecan your body absorbs and uses.

I want to be honest about the strength here: this is theoretical and only seen in test-tube studies, not in real patients. The interaction is rated minor. Still, irinotecan is serious chemotherapy with real side effects like diarrhea and low blood counts, so this isn't something to wing on your own. Please run any supplement, including passion flower, past your oncology team before adding it.

Contact Dr. Brian directly if you have additional questions on this interaction
References
  1. Schäfer AM, Gilgen PM, Spirgi C, et al. Constituents of Passiflora incarnata, but Not of Valeriana officinalis, Interact with the Organic Anion Transporting Polypeptides (OATP)2B1 and OATP1A2. Planta Med. 2021. PubMed
Minor

CYTOCHROME P450 3A4 (CYP3A4) SUBSTRATES

2 of 2

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

Theoretically, passion flower might decrease the effects of CYP3A4 substrates.
In vitro research suggests that passion flower can induce CYP3A4 enzymes, albeit to a much lower degree than rifampin, a known CYP3A4 inducer.
Severity Minor 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 passion flower and your irinotecan (Camptosar). Your liver uses an enzyme called CYP3A4 to help process irinotecan into its active cancer-fighting form. Lab-dish studies hint that passion flower might gently speed up that enzyme, which in theory could shift how much active drug your body makes from each dose.

I want to be honest with you, though: this concern comes only from test-tube research, the effect looked weak (much milder than known boosters), and it's rated a minor, possible interaction. So please don't panic. But because irinotecan is a powerful chemo drug with a tight margin between helping and causing harm (like low blood counts, nausea, and diarrhea), never add passion flower on your own. Run it by your oncology team or pharmacist first.

Contact Dr. Brian directly if you have additional questions on this interaction
References
  1. Mazzari ALDA, Lacerda MG, Milton FA, et al. In vitro effects of European and Latin-American medicinal plants in CYP3A4 gene expression, glutathione levels, and P-glycoprotein activity. Front Pharmacol 2022;13:826395. 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

Passion Flower Also Interacts With Other Medications

Passion Flower has 248 moderate, 587 minor known drug interactions in our database — the Irinotecan one above is among them. If you take anything else, check it against the full list below.

Moderate 248 Minor 587 No known interaction 1,995 (incl. Irinotecan)
Taking anything else?

Check Another of Your Medications Against Passion Flower

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

From our Q&A

Questions About Passion Flower or Irinotecan

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

This page covers Passion Flower only. If you take other supplements — a multivitamin, a sleep aid, something for joints — the Irinotecan page lists 153 supplements it has a documented interaction with, worst first, each one explained.

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

By severity: 5 major · 107 moderate · 41 minor.

From our pharmacist’s overview on the Irinotecan page

“St. John's wort is the single riskiest supplement for anyone receiving irinotecan (Camptosar, Onivyde).”

Reviewed by 2 · Jul 18, 2026

Open the Irinotecan interaction page

One more smart check

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

We hold 2,129 real supplement products containing Passion Flower, each one broken down to its full ingredient list — and combination products often carry several ingredients besides Passion Flower. Your product may carry other ingredients that interact with Irinotecan too, on top of Passion Flower — 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 Passion Flower and Irinotecan 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 Passion Flower
Top 10%

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

29 days ago today
Medication Irinotecan
Steady interest

#2,140 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 Passion Flower

What is Passion Flower?

Passion Flower
  • Anxiety and stress
  • Trouble sleeping
  • Restlessness
  • Mild nervous tension
  • Muscle tension

Passion flower is a traditional calming herb that many people use for anxiety and sleep. Early studies hint it may help with mild anxiety and restlessness, but the evidence is limited and more research is needed. It is generally well tolerated short-term, but should be avoided in pregnancy and discussed with your pharmacist or doctor first.

Read the full Passion Flower monograph & all interactions
Medication

About Irinotecan Lipid Complex Injection

What Is Irinotecan Lipid Complex Injection Used For?

Brand names: Camptosar, Onivyde

  • Irinotecan lipid complex is used in combination with other medications to treat pancreatic cancer that has spread to other parts of the body that has worsened after treatment with other chemotherapy medications. Irinotecan lipid complex is in a class of antineoplastic medications called topoisomerase I inhibitors. It works by stopping the growth of cancer cells.

See full Irinotecan Lipid Complex Injection drug information
Keep checking

Other Drugs & Passion Flower

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

0Major
248Moderate
587Minor
1,994No known interaction
248 Moderate 587 Minor 1,994 No interaction
Moderate

248 interactions

Showing 60 of 248 moderate interactions — see all 248 on the Passion Flower page.

Minor

587 interactions

Showing 60 of 587 minor interactions — see all 587 on the Passion Flower page.

No interaction 1,994 drugs checked — show the list

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

Showing the 60 most looked-up of 1,994 medications checked with no known interaction — see the full Passion Flower list.

See the full Passion Flower interactions page
See every supplement checked against Irinotecan, 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
Passion Flower monograph › Uses, safety, and every drug interaction in one place Irinotecan supplement interactions › Every supplement checked against Irinotecan, ranked by severity Irinotecan Lipid Complex Injection 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 Passion Flower and Irinotecan Together: Common Questions

Can you take Passion Flower with Irinotecan?
There is only a minor interaction, which is usually not serious. Read the full details on this page and confirm with your pharmacist before combining them.
Why are there 2 interactions listed for Passion Flower and Irinotecan?
Irinotecan belongs to more than one drug category, and Passion Flower 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 Passion Flower and Irinotecan interaction?
We rate it Minor. This interaction is generally not clinically significant, but it remains worth noting and discussing with your pharmacist.

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

Still Have a Question About Irinotecan and Passion Flower?

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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.