Drug & supplement interaction

Great Plantain + Lapatinib

Lapatinib brand name: Tykerb.

No Known Interaction
Medically reviewed by · Updated July 2026 · Pair last verified Sep 20, 2026
The bottom line No known interaction

We found no known interaction between Great Plantain and Lapatinib in our sources. Absence of a documented interaction is not the same as proven safety, and does not guarantee one does not exist. Do not start, stop, or change a medication or supplement based on this page; confirm with your pharmacist or doctor first. Additionally, although there is no interaction, the two are separately associated with some of the same side effects, which would make a new symptom harder to attribute to one or the other.

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Interaction report

Great Plantain and Lapatinib

We checked these two against our interaction database. Here is what we found.

No Known Interaction Found

We did not find a documented interaction between Lapatinib and Great Plantain in our sources. This does not guarantee that the combination is completely free of risk — there is often limited research on supplements and herbal products, especially around drug interactions.

If you decide to take both, the practical routine is simple: add one new thing at a time and note the date you started it. If the combination is going to disagree with you, it usually shows in the first days to a couple of weeks — and a start date turns “I’ve been feeling off” into something a pharmacist can actually work with. Do not stop a prescribed medicine on your own.

Always talk with your pharmacist or doctor before making changes to your medications or supplements, particularly if you take several medications or have an ongoing health condition.

Great Plantain safety at a glance

Great Plantain overall Use caution Generally considered well tolerated for most adults, but human safety data are limited.
Pregnancy Likely Unsafe When used orally because it can increase uterine tone. Read the full pregnancy detail
Breastfeeding Avoid Safety while breastfeeding is unknown, so avoid medicinal amounts.

Pregnancy & breastfeeding ratings are from Natural Medicines (Therapeutic Research Center) — the full detail is in the Special populations card below. Safety guidance is general; always confirm with your pharmacist or doctor for your situation.

Still wondering about combining Lapatinib and Great Plantain? Ask Dr. Brian Staiger, PharmD, BCPS directly ›
How we checked

Why No Interaction Is Listed for Lapatinib

Interactions in our licensed database are recorded against drug classes, not just single drug names. Lapatinib is filed under 3 classifications — cytochrome p450 3a4 (cyp3a4) inhibitors, cytochrome p450 3a4 (cyp3a4) substrates, oral drugs. Great Plantain has documented interactions with 1 drug class — the most serious being warfarin (coumadin) (moderate) — and none of Lapatinib’s classifications are among them.

Classification data comes from our licensed Natural Medicines dataset. A medication can belong to classes beyond those recorded there, so this describes how the check was run — it is not a safety guarantee.

Keep it in perspective

Great Plantain Does Interact With Other Medications

Great Plantain has 2 moderate known drug interactions in our database — Lapatinib isn’t one of them. If you take anything else, check it against the full list below.

Moderate 2 No known interaction 2,828 (incl. Lapatinib)
Taking anything else?

Check Another of Your Medications Against Great Plantain

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

What to actually watch for

No Interaction Found — But Data Suggests Great Plantain and Lapatinib May Share a Side Effect

This is not an interaction. Neither one changes how your body handles the other, and nothing here says they react together. What our sources do show is that each has separately been linked to the effects below — so taking both can make those effects more likely to turn up, and harder to pin on one or the other if they do.

  • A skin rash reported in 6.9% of FDA reports for Lapatinib Additional detail

    Great Plantain

    “Topically, application can cause allergic contact dermatitis in some individuals (4).”

    Great Plantain · Natural Medicines adverse-effect record, reported in dermatitis.

    1 source cited
    1. 4. Newall CA, Anderson LA, Philpson JD. Herbal Medicine: A Guide for Healthcare Professionals. London, UK: The Pharmaceutical Press, 1996.

    Lapatinib

    Listed in the ADVERSE REACTIONS section of the FDA label for Lapatinib, and in voluntary FDA adverse-event reports. Read the label on DailyMed ›

Effects for Lapatinib come from the ADVERSE REACTIONS section of its FDA label; effects for Great Plantain come from the Natural Medicines adverse-effect record, quoted above. Where a percentage is shown, it is the share of 15,427 voluntary FDA FAERS reports for Lapatinib that mention that effect — a reporting proportion, not an incidence rate and not evidence the drug caused it. Wording is matched across sources by our own clinical vocabulary, so treat this as a prompt to pay attention, not a diagnosis.

Special populations

Great Plantain in Pregnancy & Breastfeeding

Pregnancy Likely Unsafe

When used orally because it can increase uterine tone.

DISCLAIMER: This tool is intended for informational purposes only, and should not be interpreted as specific medical advice. Patients should consult with a qualified healthcare provider before making decisions about therapies and/or health conditions.© 2026 Therapeutic Research Center

Everything else you take

See Every Supplement That Interacts With Lapatinib

This page covers Great Plantain only. If you take other supplements — a multivitamin, a sleep aid, something for joints — the Lapatinib page lists 143 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 · 100 moderate · 40 minor.

From our pharmacist’s overview on the Lapatinib page

“Of the 143 supplements on file for lapatinib (Tykerb), nearly all press on the same point, the CYP3A4 enzyme that clears this HER2-targeted breast cancer drug. That deserves real caution, since lapatinib only works when its blood level stays in range.”

Reviewed by 2 · Jul 18, 2026

Open the Lapatinib interaction page

How much people look this up

Where Great Plantain and Lapatinib 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 Great Plantain
Steady interest

#1,045 of 1,452 supplements looked up here in the last 7 days

29 days ago today
Medication Lapatinib
Steady interest

#2,248 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.

Where does our data come from?
  • Source: the Natural Medicines (TRC Healthcare) clinical database — the evidence-graded professional reference for herb & supplement interactions.
  • Citation library: 103,510 references behind our interaction content, 65,311 of them resolved to verified PubMed/DOI sources. See every Great Plantain reference on this page ↓
  • Freshness: we automatically re-check this combination every week — this pair was last verified September 20, 2026. The Great Plantain and Lapatinib records this page draws on were last updated July 11, 2026.
  • What “no known interaction” means: no documented interaction in the sources above — not a guarantee of safety. Supplements are studied far less than prescription drugs, so we say exactly what the evidence supports, and nothing more.
Data structure & sourcing designed and verified by .
Supplement

About Great Plantain

What is Great Plantain?

  • Minor wounds and skin irritation
  • Insect bites and stings
  • Coughs and sore throat
  • Digestive upset
  • Mild inflammation

Great Plantain is a common weed traditionally used on the skin for minor wounds and bites, and as a tea for coughs or stomach upset. Human evidence for most of these uses is limited, though the plant appears generally well tolerated. Talk with your pharmacist or doctor before using it, especially if you are pregnant, breastfeeding, or have a health condition.

Plantago major · Plantaginaceae · Leaves and seeds · Tea, capsules, tinctures, topical salves and ointments, fresh crushed leaves (poultice)

An interaction check asks whether these two react with each other — it does not ask whether Great Plantain is a good idea for someone in your situation. Here is what our Great Plantain record says about it on its own.

Great Plantain: dosing

There is no well-established standardized dose for Great Plantain. Traditional use varies widely, and the amount of active compounds differs between products and plant sources.If you choose to use it, follow the directions on the product label and do not exceed the recommended amount. A pharmacist or doctor can help you decide whether it is appropriate for you and review your other medications and health conditions first.

From our Great Plantain monograph — the full record covers uses, side effects and every documented interaction.

Read the full Great Plantain monograph & all interactions
Medication

About Lapatinib

What Is Lapatinib Used For?

Brand name: Tykerb

Lapatinib tablets — sold under the brand name Tykerb — are used to treat advanced or metastatic breast cancer in patients whose tumors overexpress the HER2 protein. They are always used in combination with another medicine, not alone.

Tykerb is approved in combination with capecitabine for HER2-positive advanced or metastatic breast cancer in patients who have already received prior treatment including an anthracycline, a taxane, and trastuzumab, and whose disease has progressed on trastuzumab. Tykerb is also approved in combination with letrozole for postmenopausal women with hormone receptor-positive, HER2-positive metastatic breast cancer when hormonal therapy is appropriate.

Most-Reported Side Effects for Lapatinib

From FAERS, the FDA’s public side-effect reporting system (15,427 reports, all brands). Reports are voluntary and are not proof the drug caused the effect.

Diarrhea 4,174 reports
Nausea 1,615 reports
Fatigue 1,305 reports
Vomiting 1,209 reports
Rash 1,061 reports
See full Lapatinib drug information
Keep checking

Other Drugs & Great Plantain

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

0Major
2Moderate
0Minor
2,827No known interaction
2 Moderate 2,827 No interaction
Moderate

2 interactions

No interaction 2,827 drugs checked — show the list

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

Showing the 60 most looked-up of 2,827 medications checked with no known interaction — see the full Great Plantain list.

See the full Great Plantain interactions page
See every supplement checked against Lapatinib, ranked by severity
Evidence & sources

Great Plantain References

The 3 references that drive our Great Plantain monograph and interaction data, from the evidence-graded Natural Medicines (TRC Healthcare) database. Citations with a link open the study on PubMed or the publisher’s site.

  1. Newall CA, Anderson LA, Philpson JD. Herbal Medicine: A Guide for Healthcare Professionals. London, UK: The Pharmaceutical Press, 1996.
  2. Brinker F. Herb Contraindications and Drug Interactions. 2nd ed. Sandy, OR: Eclectic Medical Publications, 1998.
  3. Adom MB, Taher M, Mutalabisin MF, et al. Chemical constituents and medical benefits of Plantago major. Biomed Pharmacother. 2017;96:348-360. PubMed

Medication overviews come from MedlinePlus (NIH); supplement label data from the NIH Dietary Supplement Label Database. Content is written and reviewed by licensed HelloPharmacist pharmacists — see our data sources and editorial standards.

Pharmacist Counseling Corner

Taking Great Plantain and Lapatinib Together: Common Questions

Is it safe to take Great Plantain with Lapatinib?
We do not list a known interaction between Great Plantain and Lapatinib. That does not guarantee the combination is risk-free, so confirm with your pharmacist or doctor — especially if you take other medications or have a health condition.
Do Great Plantain and Lapatinib have any of the same side effects?
Yes — our sources link each of them separately to one of the same effects. That is not an interaction: neither changes how your body handles the other. It does mean that if one of those effects turns up, it can be harder to tell which one is behind it. They are listed on this page with the source behind each.
How was the Great Plantain and Lapatinib combination checked?
Interactions in our licensed database are recorded against drug classes. Lapatinib is filed under 3 classifications, and Great Plantain has documented interactions with 1 drug class — none of Lapatinib's classifications are among them. A medication can belong to classes beyond those recorded in our dataset, so this describes how the check was run rather than guaranteeing safety.
Does Great Plantain interact with any other medications?
Yes. Great Plantain has 2 documented drug interactions in our database — Lapatinib is simply not one of them. If you take anything else, it is worth checking each one; they are all listed on this page.
Does Lapatinib interact with any supplements?
Yes. Lapatinib has documented interactions with 143 supplements in our database — Great Plantain is not one of them. The Lapatinib interaction page linked on this page lists every one, ranked by severity.

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

Where next

Keep Exploring

Great Plantain monograph Uses, safety profile, and every drug interaction in one place Lapatinib drug information The full plain-English guide to this medication Lapatinib supplement interactions Every supplement checked against Lapatinib, ranked by severity Supplement interaction checker Check any supplement or product against your medications Browse medications A–Z Every drug we’ve checked against herbs & supplements References The 3 citations behind this page Ask a pharmacist Free, personal answer from our licensed team

Still Have a Question About Lapatinib and Great Plantain?

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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.