Drug & supplement interaction

Macadamia Nut + Letrozole

Letrozole brand name: Femara.

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 Macadamia Nut and Letrozole 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.

Know someone taking this? Share
Facebook Post Reddit Email
On this page
Interaction report

Macadamia Nut and Letrozole

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 Letrozole and Macadamia Nut 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 Macadamia Nut at all — not against Letrozole, 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.

Macadamia Nut safety at a glance

Macadamia Nut overall Generally safe Macadamia nuts are widely eaten as a food and are generally safe for people without nut allergies.
Pregnancy Likely Safe When used as food. Read the full pregnancy detail
Breastfeeding Likely Safe When used as food. 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 Letrozole and Macadamia Nut? Ask Dr. Brian Staiger, PharmD, BCPS directly ›
What to actually watch for

What Macadamia Nut Itself Has Been Linked To

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

  • A severe allergic reaction / An allergic reaction Worth acting on Additional detail

    “Orally, macadamia nut is well tolerated.

    Serious Adverse Effects (Rare):

    All routes of administration: Allergic reactions, including anaphylaxis and contact dermatitis.”

    Macadamia Nut · Natural Medicines adverse-effect record, reported in dermatitis.

    “Orally, eating macadamia nuts or macadamia nut oil can cause allergic reactions, including anaphylaxis. Processing methods may affect the allergenicity of macadamia nuts.

    Topically, occupational exposure to macadamia nut shells has resulted in allergic contact dermatitis.”

    Macadamia Nut · Natural Medicines adverse-effect record, reported in dermatitis.

    6 sources cited
    1. 12600. Lerch M, Egger C, Bircher AJ. Allergic reactions to macadamia nut. Allergy 2005;60:130-1. PubMed
    2. 12601. Pallares DE. Allergy to macadamia nut. Ann Allergy Asthma Immunol 2000;85:385-6. PubMed
    3. 100019. De Knop KJ, Hagendorens MM, Bridts CH, Stevens WJ, Ebo DG. Macadamia nut allergy: 2 case reports and a review of the literature. Acta Clin Belg. 2010;65(2):129-32.
    4. 100031. Randhawa I, Morphew T, Marsteller NL. Correlation of negative skin-prick test results for tree nuts and successful tree nut challenges among children with peanut allergy. Allergy Asthma Proc. 2018;39(6):456-460. PubMed
    5. 100032. Polk BI, Dinakarpandian D, Nanda M, Barnes C, Dinakar C. Association of tree nut and coconut sensitizations. Ann Allergy Asthma Immunol. 2016;117(4):412-416. PubMed
    6. 100033. Ekbote A, Hayman G, Bansal A. Macadamia nut allergy: potentially misleading specific IgE results. Allergy. 2010;65(10):1345. PubMed
  • A skin rash Additional detail

    Recorded for Macadamia Nut in the same Natural Medicines adverse-effect record shown under A severe allergic reaction / An allergic reaction above.

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

Special populations

Macadamia Nut in Pregnancy & Breastfeeding

Pregnancy And Lactation Likely Safe

When used as food.

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

From our Q&A

Questions About Macadamia Nut or Letrozole

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

This page covers Macadamia Nut only. If you take other supplements — a multivitamin, a sleep aid, something for joints — the Letrozole page lists 142 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), 7-methoxyflavone (moderate) and Acacia Rigidula (moderate).

By severity: 3 major · 99 moderate · 40 minor.

From our pharmacist’s overview on the Letrozole page

“Letrozole (Femara) is prescribed to keep hormone-driven breast cancer from returning, so a supplement that shifts its blood level can quietly undercut treatment. Give this list of 142 ingredients genuine respect, and learn the three major entries first.”

Reviewed by 2 · Jul 18, 2026

Open the Letrozole interaction page

How much people look this up

Where Macadamia Nut and Letrozole 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 Macadamia Nut
Top half

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

29 days ago today
Medication Letrozole
Top 5%

#50 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 Macadamia Nut reference on this page ↓
  • Freshness: we automatically re-check this combination every week — this pair was last verified September 13, 2026. The Macadamia Nut and Letrozole 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 Macadamia Nut

What is Macadamia Nut?

  • Heart health
  • Healthy snacking
  • Weight management
  • Skin and hair care (oil)
  • Source of healthy fats

Macadamia nuts are a nutritious food rich in healthy monounsaturated fats, fiber, and minerals, and they can be a part of a heart-healthy diet. They are mainly eaten as a food rather than used as a medicine, and the strongest evidence supports them as a wholesome snack rather than a treatment for any disease. People with tree nut allergies should avoid them.

Macadamia integrifolia · Proteaceae · Nut (seed kernel) and nut oil · Whole nuts, nut butter, nut oil, milk, flour

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

Macadamia Nut: dosing

There is no official medicinal dose for macadamia nuts because they are a food, not a standardized supplement. A common snack portion is a small handful of nuts.If you use a macadamia product such as oil, butter, or a supplement, follow the directions on the product label.

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

Read the full Macadamia Nut monograph & all interactions
Medication

About Letrozole

What Is Letrozole Used For?

Brand name: Femara

Letrozole (brand name Femara) is used to treat breast cancer in postmenopausal women whose tumors are driven by estrogen. It is used in three settings: as adjuvant (after-surgery) treatment for hormone receptor positive early breast cancer; as extended adjuvant treatment for women who have already completed about five years of tamoxifen therapy; and as first- or second-line treatment for locally advanced or metastatic (spread) breast cancer.

Femara is specifically indicated for first-line treatment of hormone receptor positive or receptor-unknown locally advanced or metastatic breast cancer, and for advanced breast cancer in women whose disease has progressed after antiestrogen therapy.

See full Letrozole drug information
Keep checking

Other Drugs & Macadamia Nut

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

See the full Macadamia Nut interactions page
See every supplement checked against Letrozole, ranked by severity
Evidence & sources

Macadamia Nut References

The 11 references that drive our Macadamia Nut 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. Garg ML, Blake RJ, Wills RB. Macadamia nut consumption lowers plasma total and LDL cholesterol levels in hypercholesterolemic men. J Nutr 2003;133:1060-3. PubMed
  2. Curb JD, Wergowske G, Dobbs JC, et al. Serum lipid effects of a high-monounsaturated fat diet based on macadamia nuts. Arch Intern Med 2000;160:1154-8. PubMed
  3. Lerch M, Egger C, Bircher AJ. Allergic reactions to macadamia nut. Allergy 2005;60:130-1. PubMed
  4. Pallares DE. Allergy to macadamia nut. Ann Allergy Asthma Immunol 2000;85:385-6. PubMed
  5. Teuber SS, Brown RL, Haapanen LA. Allergenicity of gourmet nut oils processed by different methods. J Allergy Clin Immunol 1997;99:502-7. PubMed
  6. Knight TE, Hausen BM. Dermatitis in a nutshell: occupational exposure to Macadamia integrifolia. J Am Acad Dermatol 1996;35:482-4. PubMed
  7. De Knop KJ, Hagendorens MM, Bridts CH, Stevens WJ, Ebo DG. Macadamia nut allergy: 2 case reports and a review of the literature. Acta Clin Belg. 2010;65(2):129-32.
  8. Randhawa I, Morphew T, Marsteller NL. Correlation of negative skin-prick test results for tree nuts and successful tree nut challenges among children with peanut allergy. Allergy Asthma Proc. 2018;39(6):456-460. PubMed
  9. Polk BI, Dinakarpandian D, Nanda M, Barnes C, Dinakar C. Association of tree nut and coconut sensitizations. Ann Allergy Asthma Immunol. 2016;117(4):412-416. PubMed
  10. Ekbote A, Hayman G, Bansal A. Macadamia nut allergy: potentially misleading specific IgE results. Allergy. 2010;65(10):1345. PubMed
  11. Herbst RA, Wahl R, Frosch PJ. Specific IgE reactivity and identification of potential allergens in macadamia allergy. J Eur Acad Dermatol Venereol. 2010;24(11):1361-3. 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 Macadamia Nut and Letrozole Together: Common Questions

Is it safe to take Macadamia Nut with Letrozole?
We do not list a known interaction between Macadamia Nut and Letrozole. 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 Letrozole interact with any supplements?
Yes. Letrozole has documented interactions with 142 supplements in our database — Macadamia Nut is not one of them. The Letrozole 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

Macadamia Nut monograph Uses, safety profile, and every drug interaction in one place Letrozole drug information The full plain-English guide to this medication Letrozole supplement interactions Every supplement checked against Letrozole, 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 11 citations behind this page Ask a pharmacist Free, personal answer from our licensed team

Still Have a Question About Letrozole and Macadamia Nut?

Our pharmacists answer your medication & supplement questions — free.

Ask a pharmacist

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.