Drug & supplement interaction

Myrtle + 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 Myrtle 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

Myrtle 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 Myrtle 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 Myrtle 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.

Myrtle safety at a glance

Myrtle overall Use caution Likely safe in small amounts as food or tea, but concentrated extracts and oils need caution.
Pregnancy Likely Unsafe When used orally; avoid using. Read the full pregnancy detail
Breastfeeding Likely Unsafe When used orally; avoid using. Read the full breastfeeding detail

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 Myrtle? Ask Dr. Brian Staiger, PharmD, BCPS directly ›
What to actually watch for

What Myrtle Itself Has Been Linked To

This is not an interaction — nothing below involves Lapatinib. It is the side-effect record for Myrtle on its own, from the licensed Natural Medicines monograph. If something new turns up after you add Myrtle, this list is the first place to look. One entry is worth acting on rather than waiting out — marked below.

  • Wheezing Worth acting on Additional detail

    “Orally, consumption of very large amounts of undiluted myrtle leaf oil might lead to respiratory failure and collapse (18).

    Topically, facial contact with myrtle oil preparations may cause glottal or bronchial spasm, asthma-like attacks, or respiratory failure in infants and children (18).”

    Myrtle · Natural Medicines adverse-effect record, reported in asthma.

    1 source cited
    1. 18. Gruenwald J, Brendler T, Jaenicke C. PDR for Herbal Medicines. 1st ed. Montvale, NJ: Medical Economics Company, Inc., 1998.
  • Dry skin Additional detail

    “Topically, myrtle leaf extract has been reported to cause dry skin.”

    Myrtle · Natural Medicines adverse-effect record, reported in dry skin.

    1 source cited
    1. 106777. Salmanian M, Shirbeigi L, Hashem-Dabaghian F, et al. The Effects of Myrtle (Myrtus communis) and Clindamycin Topical Solution in the Treatment of Mild to Moderate Acne Vulgaris: A Comparative Split-Face Study. J Pharmacopuncture 2020;23(4):220-229.
  • Low blood pressure Additional detail

    “Orally, very large amounts of undiluted myrtle leaf oil might lead to low blood pressure and circulatory disorders due to the cineole constituent (18).”

    Myrtle · Natural Medicines adverse-effect record, reported in hypotension.

    1 source cited
    1. 18. Gruenwald J, Brendler T, Jaenicke C. PDR for Herbal Medicines. 1st ed. Montvale, NJ: Medical Economics Company, Inc., 1998.
  • Constipation Additional detail

    “Orally, myrtle berry extract has been reported to cause constipation in infants and young children.”

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

    1 source cited
    1. 106781. Paknejad MS, Eftekhari K, Rahimi R, Vigeh M, Naghizadeh A, Karimi M. Myrtle (Myrtus communis L.) fruit syrup for gastroesophageal reflux disease in children: A double-blind randomized clinical trial. Phytother Res 2021;35(11):6369-6376.

Everything above comes from the Natural Medicines adverse-effect record for Myrtle — expand a row for the licensed statement it rests on. We read the ADVERSE REACTIONS section of Lapatinib’s FDA label too, and the two lists don’t meaningfully overlap — which is why no Lapatinib column appears here.

Special populations

Myrtle in Pregnancy & Breastfeeding

Pregnancy And Lactation Likely Unsafe

When used orally; 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

Everything else you take

See Every Supplement That Interacts With Lapatinib

This page covers Myrtle 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 Myrtle as Part of a Dietary Supplement Product? Check It for Interactions

We hold 33 real supplement products containing Myrtle, each one broken down to its full ingredient list — and combination products often carry several ingredients besides Myrtle. Even though Myrtle 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 Myrtle 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 Myrtle
Steady interest

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

29 days ago today
Medication Lapatinib
Steady interest

#1,678 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 Myrtle reference on this page ↓
  • Freshness: we automatically re-check this combination every week — this pair was last verified September 20, 2026. The Myrtle and Lapatinib records this page draws on were last updated July 10, 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 Myrtle

What is Myrtle?

  • Coughs and respiratory congestion
  • Digestive upset
  • Antimicrobial and wound care
  • Skin conditions
  • Urinary complaints

Myrtle (Myrtus communis) is a Mediterranean shrub used traditionally for respiratory, digestive, and skin complaints. Modern research is mostly limited to laboratory and small studies, so its benefits in people are not well proven. Use cautiously, follow product labels, and talk to your pharmacist or doctor first—especially since the essential oil should never be swallowed.

Myrtus communis · Myrtaceae · Leaves, berries, flowers, and essential oil · Tea, capsules, extracts, essential oil, topical preparations

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

Myrtle: dosing

There is no well-established standard dose for myrtle. Amounts used in traditional practice and studies vary widely depending on the form—tea, extract, capsule, or oil.Because products differ in strength and quality, the safest approach is to follow the directions on the product label and not exceed them.

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

Read the full Myrtle 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 & Myrtle

Browse every other medication we’ve checked against Myrtle — 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 Myrtle 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 Myrtle list.

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

Myrtle References

The 3 references that drive our Myrtle 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. Gruenwald J, Brendler T, Jaenicke C. PDR for Herbal Medicines. 1st ed. Montvale, NJ: Medical Economics Company, Inc., 1998.
  2. Salmanian M, Shirbeigi L, Hashem-Dabaghian F, et al. The Effects of Myrtle (Myrtus communis) and Clindamycin Topical Solution in the Treatment of Mild to Moderate Acne Vulgaris: A Comparative Split-Face Study. J Pharmacopuncture 2020;23(4):220-229.
  3. Paknejad MS, Eftekhari K, Rahimi R, Vigeh M, Naghizadeh A, Karimi M. Myrtle (Myrtus communis L.) fruit syrup for gastroesophageal reflux disease in children: A double-blind randomized clinical trial. Phytother Res 2021;35(11):6369-6376.

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 Myrtle and Lapatinib Together: Common Questions

Is it safe to take Myrtle with Lapatinib?
We do not list a known interaction between Myrtle 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 — Myrtle 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

Myrtle 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 Myrtle?

Our pharmacists answer your medication & supplement questions — free.

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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.