Drug & supplement interaction

Tribulus + Lapatinib

Lapatinib brand name: Tykerb.

No Known Interaction
Medically reviewed by · Updated July 2026 · Pair last verified Sep 13, 2026
The bottom line No known interaction

We found no known interaction between Tribulus 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

Tribulus 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 Tribulus 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.

Tribulus safety at a glance

Tribulus overall Use caution Often well tolerated short-term in healthy adults, but quality and long-term safety data are limited.
Pregnancy Possibly Unsafe When used orally. Animal research suggests that tribulus might adversely affect fetal development; avoid using. Read the full pregnancy detail
Breastfeeding Avoid Avoid while breastfeeding due to a lack of reliable safety information.

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 Tribulus? 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. Tribulus has documented interactions with 3 drug classes — the most serious being antidiabetes drugs (moderate), antihypertensive drugs (moderate) and lithium (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

Tribulus Does Interact With Other Medications

Tribulus has 259 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 259 No known interaction 2,571 (incl. Lapatinib)
Taking anything else?

Check Another of Your Medications Against Tribulus

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

What to actually watch for

No Interaction Found — But Data Suggests Tribulus and Lapatinib May Share Several of the Same Side Effects

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.

  • Diarrhea / Vomiting / Nausea reported in 27.1% of FDA reports for Lapatinib Additional detail

    Tribulus

    “Orally, tribulus can cause abdominal pain, cramping, nausea, vomiting, diarrhea, and constipation. However, in one study, the rates of these gastrointestinal complaints were similar for patients taking tribulus and those receiving placebo.”

    Tribulus · Natural Medicines adverse-effect record, reported in constipation.

    2 sources cited
    1. 92022. Akhtari E, Raisi F, Keshavarz M, et al. Tribulus terrestris for treatment of sexual dysfunction in women: randomized double-blind placebo-controlled study. Daru 2014;22:40. PubMed
    2. 92027. Postigo S, Lima SM, Yamada SS, et al. Assessment of the effects of Tribulus terrestris on sexual function of menopausal women. Rev Bras Ginecol Obstet 2016;38(3):140-6. PubMed

    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 ›

Reported for Tribulus but not commonly for Lapatinib: kidney problems, stomach pain, constipation and liver problems.

Effects for Lapatinib come from the ADVERSE REACTIONS section of its FDA label; effects for Tribulus 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

Tribulus in Pregnancy & Breastfeeding

Pregnancy Possibly Unsafe

When used orally. Animal research suggests that tribulus might adversely affect fetal development; avoid using.

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

Overlapping uses

What Lapatinib Is Prescribed For, and What Tribulus Has Been Studied For

These two come up together because they touch the same health topic — not because they do the same job. Lapatinib is a prescription medicine with approved uses on its FDA label. Tribulus is a supplement: what follows is what researchers have looked at it for, and how strong that evidence is.

Lapatinib is prescribed for: Lapatinib tablets are used in combination with other medicines to treat certain types of advanced or metastatic breast cancer in patients whose tumors overexpress HER2 (a protein that drives tumor growth). It is not used alone. Specifically, lapatinib tablets are used with capecitabine for HER2-positive advanced or metastatic breast cancer in patients who have already received prior therapy (including certain chemotherapy drugs and trastuzumab). Lapatinib tablets are also used with letrozole for postmenopausal women with hormone receptor-positive, HER2-positive metastatic breast cancer when hormonal therapy is appropriate.

Read the rest of what Lapatinib is prescribed for

Tykerb is the brand name product with these same indicated uses.

Tribulus has been studied for:

  • Cancer studied, not established Tribulus has been studied for this. Natural Medicines rates the evidence: Insufficient Reliable Evidence To Rate Read what the research shows

    Tribulus for cancer

    Although there is interest in using oral tribulus for cancer, there is insufficient reliable information about the clinical effects of tribulus for this condition.

Effectiveness ratings and the research summaries above are the verbatim record from the Natural Medicines database, which grades evidence from “Effective” down to “Insufficient Reliable Evidence To Rate”. A rating below the top of that scale means researchers have looked at it — not that it works, and never that it can stand in for a prescribed medicine. Do not stop or replace Lapatinib on your own; if you are taking Tribulus for the same health topic, tell your prescriber, especially if the medicine is being adjusted to a target.

Everything else you take

See Every Supplement That Interacts With Lapatinib

This page covers Tribulus 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

One more smart check

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

We hold 1,680 real supplement products containing Tribulus, each one broken down to its full ingredient list — and combination products often carry several ingredients besides Tribulus. Even though Tribulus itself has no known interaction with Lapatinib, another ingredient on your label might. Find your product and we’ll check every ingredient on its label:

How much people look this up

Where Tribulus 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 Tribulus
Top 10%

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

29 days ago today
Medication Lapatinib
Steady interest

#2,771 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 Tribulus reference on this page ↓
  • Freshness: we automatically re-check this combination every week — this pair was last verified September 13, 2026. The Tribulus 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 Tribulus

What is Tribulus?

Tribulus
  • Low libido and sexual function
  • Athletic performance and muscle building
  • Testosterone support
  • Male and female fertility
  • General 'vitality' or wellness

Tribulus is a plant supplement most often marketed to boost libido, testosterone, and athletic performance, but the human evidence behind these claims is weak and inconsistent. It is generally well tolerated by healthy adults in the short term, but it should be avoided during pregnancy and breastfeeding and discussed with your pharmacist or doctor before use.

Tribulus terrestris · Zygophyllaceae · Fruit, leaf, and root · Capsules, tablets, powders, tinctures, and standardized extracts

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

Tribulus: dosing

There is no well-established standard dose for Tribulus. Studies have used a range of doses and different extracts, often standardized to a percentage of saponins, which makes it hard to compare products or recommend one amount.The best approach is to follow the directions on the specific product label and not exceed them.

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

Read the full Tribulus monograph & all interactions
Medication

About Lapatinib

What Is Lapatinib Used For?

Brand name: Tykerb

Lapatinib tablets are used in combination with other medicines to treat certain types of advanced or metastatic breast cancer in patients whose tumors overexpress HER2 (a protein that drives tumor growth). It is not used alone.

Specifically, lapatinib tablets are used with capecitabine for HER2-positive advanced or metastatic breast cancer in patients who have already received prior therapy (including certain chemotherapy drugs and trastuzumab). Lapatinib tablets are also used with letrozole for postmenopausal women with hormone receptor-positive, HER2-positive metastatic breast cancer when hormonal therapy is appropriate. Tykerb is the brand name product with these same indicated uses.

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 & Tribulus

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

0Major
259Moderate
0Minor
2,570No known interaction
259 Moderate 2,570 No interaction
Moderate

259 interactions

Showing 60 of 259 moderate interactions — see all 259 on the Tribulus page.

No interaction 2,570 drugs checked — show the list

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

Showing the 60 most looked-up of 2,570 medications checked with no known interaction — see the full Tribulus list.

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

Tribulus References

The 10 references that drive our Tribulus 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. Sharifi AM, Darabi R, Akbarloo N. Study of antihypertensive mechanism of Tribulus terrestris in 2K1C hypertensive rats: role of tissue ACE activity. Life Sci 2003;73:2963-71. PubMed
  2. Walker D, Bird A, Flora T, O'Sullivan B. Some effects of feeding Tribulus terrestris, Ipomoea lonchophylla and the seed of Abelmoschus ficulneus on fetal development and the outcome of pregnancy in sheep. Reprod Fertil Dev 1992;4:135-44. PubMed
  3. Al-Ali M, Wahbi S, Twaij H, Al-Badr A. Tribulus terrestris: preliminary study of its diuretic and contractile effects and comparison with Zea mays. J Ethnopharmacol 2003;85:257-60. PubMed
  4. Tabakova, P., Dimitrov, M., Ognyanov, K., and et al. Clinical study of Tribestan in females with endocrine sterility. Documentation for Registration (unpublished) 1999.
  5. Akhtari E, Raisi F, Keshavarz M, et al. Tribulus terrestris for treatment of sexual dysfunction in women: randomized double-blind placebo-controlled study. Daru 2014;22:40. PubMed
  6. Ryan M, Lazar I, Nadasdy GM, et al. Acute kidney injury and hyperbilirubinemia in a young male after ingestion of Tribulus terrestris. Clin Nephrol 2015;83(3):177-83. PubMed
  7. Postigo S, Lima SM, Yamada SS, et al. Assessment of the effects of Tribulus terrestris on sexual function of menopausal women. Rev Bras Ginecol Obstet 2016;38(3):140-6. PubMed
  8. Talasaz AH, Abbasi MR, Abkhiz S, Dashti-Khavidaki S. Tribulus terrestris-induced severe nephrotoxicity in a young healthy male. Nephrol Dial Tranplant 2010;25(11):3792-3. PubMed
  9. Samani NB, Jokar A, Soveid M, Heydari M, Mosavat SH. Efficacy of the hydroalcoholic extract of Tribulus terrestris on the serum glucose and lipid profile of women with diabetes mellitus: a double-blind randomized placebo-controlled clinical trial. J Evid
  10. Siddiqui MA, Itrat M, Mobeen A, Khan MI. Efficacy of khar-i-khasak (Tribulus terrestris Linn.) in prehypertension: a randomized, double-blind, placebo-controlled trial. J Complement Integr Med. 2021.

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 Tribulus and Lapatinib Together: Common Questions

Is it safe to take Tribulus with Lapatinib?
We do not list a known interaction between Tribulus 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 Tribulus and Lapatinib have any of the same side effects?
Yes — our sources link each of them separately to 3 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.
Are Tribulus and Lapatinib used for the same thing?
They overlap in purpose, which usually means the real question is whether you need both rather than whether they are safe together. This page lists the shared uses and how strong the evidence is for Tribulus in each. That is a conversation for your prescriber, especially if Lapatinib is being adjusted to a target.
How was the Tribulus and Lapatinib combination checked?
Interactions in our licensed database are recorded against drug classes. Lapatinib is filed under 3 classifications, and Tribulus has documented interactions with 3 drug classes — 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 Tribulus interact with any other medications?
Yes. Tribulus has 259 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 — Tribulus 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

Tribulus 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 10 citations behind this page Ask a pharmacist Free, personal answer from our licensed team

Still Have a Question About Lapatinib and Tribulus?

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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.