Drug & supplement interaction

American Adder's Tongue + Lapatinib

Lapatinib brand name: Tykerb.

No Known Interaction

Medically reviewed by Dr. Brian Staiger, PharmD, BCPS · Updated June 2026 · Pair last verified Sep 13, 2026

The bottom line No known interaction

We found no known interaction between American Adder's Tongue 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.

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Interaction report

American Adder's Tongue 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 American Adder's Tongue 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.

Worth understanding: our licensed dataset holds no drug-interaction record for American Adder's Tongue at all — not against Lapatinib, and not against any other medication we track. This verdict therefore rests on the absence of any recorded data, not on research that looked at this combination and found nothing. We cannot rule an interaction out.

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.

American Adder's Tongue safety at a glance

American Adder's T... overall Use caution Human safety data is very limited, and the plant can cause stomach upset or vomiting when eaten.

Pregnancy Avoid There is not enough safety information, so it is best avoided during pregnancy.

Breastfeeding Avoid There is not enough safety information, so it is best avoided while breastfeeding.

Safety guidance is general; always confirm with your pharmacist or doctor for your situation.

Still wondering about combining Lapatinib and American Adder's Tongue? Ask Dr. Brian Staiger, PharmD, BCPS directly ›

What to actually watch for

What Lapatinib’s Own FDA Label Lists

This is not an interaction — none of it involves American Adder's Tongue. These are the most notable effects listed in the ADVERSE REACTIONS section of Lapatinib’s own FDA label, for the medication by itself. Knowing the drug’s own list makes it easier to work out the likely cause if something new turns up while you take both.

Diarrhea mentioned in 27.1% of FDA reports for Lapatinib
Acne
Mouth irritation or sores
Tiredness mentioned in 8.5% of FDA reports for Lapatinib
Vomiting mentioned in 7.8% of FDA reports for Lapatinib
A skin rash mentioned in 6.9% of FDA reports for Lapatinib
Nausea mentioned in 10.5% of FDA reports for Lapatinib

From the ADVERSE REACTIONS section of the FDA label for Lapatinib. Read the label on DailyMed › 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. American Adder's Tongue’s licensed record lists no adverse effects our clinical vocabulary could match, so there is no American Adder's Tongue side to compare — that is a limit of the record, not a statement that American Adder's Tongue has no side effects.

Everything else you take

See Every Supplement That Interacts With Lapatinib

This page covers American Adder's Tongue 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 American Adder's Tongue 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 American Adder's Tongue

Steady interest

#1,418 of 1,452 supplements looked up here in the last 7 days

29 days ago today

Medication Lapatinib

Steady interest

#2,414 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. American Adder's Tongue is not yet covered by that licensed database, so its write-up cites publicly available medical sources directly (see the references below).
Citation library: 103,510 references behind our interaction content, 65,311 of them resolved to verified PubMed/DOI sources. See every American Adder's Tongue reference on this page ↓
Freshness: we automatically re-check this combination every week — this pair was last verified September 13, 2026. The American Adder's Tongue and Lapatinib records this page draws on were last updated June 22, 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 Dr. Brian Staiger, PharmD, BCPS.

Supplement

About American Adder's Tongue

What is American Adder's Tongue?

Skin ulcers and wounds
Swollen glands
Minor skin irritation
Folk remedy for nausea (as an emetic)

American Adder's Tongue (Erythronium americanum) is a woodland lily used in traditional folk medicine, mainly as a crushed-leaf poultice for skin ulcers and wounds. There is very little modern scientific evidence to support any of its uses, and safety information is limited, so it should be used cautiously and avoided in pregnancy and breastfeeding.

Erythronium americanum · Liliaceae · Leaves and tubers (corms) · Crushed fresh leaves (poultice), juice, tea, tincture

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

American Adder's Tongue: dosing

There is no established or standardized dose for American Adder's Tongue. Because it has not been studied in modern clinical research, no safe and effective amount has been identified.If a product is sold commercially, follow the directions on the label and do not exceed them. Avoid eating raw leaves or corms, as this can cause vomiting.

From our American Adder's Tongue monograph — the full record covers uses, side effects and every documented interaction.

Read the full American Adder's Tongue 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 & American Adder's Tongue

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

0Major

0Moderate

0Minor

2,829No known interaction

2,829 No interaction

No interaction 2,829 drugs checked — show the list

We also checked American Adder's Tongue against these medications and found no known interaction in our sources. Open any page to confirm.

Showing the 60 most looked-up of 2,829 medications checked with no known interaction — see the full American Adder's Tongue list.

See the full American Adder's Tongue interactions page

See every supplement checked against Lapatinib, ranked by severity

Evidence & sources

American Adder's Tongue References

The 2 sources that drive our American Adder's Tongue monograph — publicly available pages from reputable medical and government organizations. Every link was verified to work before publishing. American Adder's Tongue is not covered by the licensed Natural Medicines interaction database, so its page cites these public sources directly.

Dietary Supplements: What You Need to Know — NIH Office of Dietary Supplements Source
Using Dietary Supplements Wisely — NIH NCCIH Source

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 American Adder's Tongue and Lapatinib Together: Common Questions

Is it safe to take American Adder's Tongue with Lapatinib?

We do not list a known interaction between American Adder's Tongue 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.

Does Lapatinib interact with any supplements?

Yes. Lapatinib has documented interactions with 143 supplements in our database — American Adder's Tongue 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

American Adder's Tongue 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 2 citations behind this page Ask a pharmacist Free, personal answer from our licensed team

Still Have a Question About Lapatinib and American Adder's Tongue?

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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.