Drug & supplement interaction

Peyote + 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 Peyote 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. 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

Peyote 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 Peyote 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.

Peyote safety at a glance

Peyote overall Avoid Peyote is a hallucinogen and a controlled substance with no established medical use as a supplement.
Pregnancy Unsafe When used orally. The active constituent of peyote, mescaline, may be teratogenic. Read the full pregnancy detail
Breastfeeding Unsafe When used orally. The active constituent of peyote, mescaline, may be teratogenic. 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 Peyote? Ask Dr. Brian Staiger, PharmD, BCPS directly ›
How we checked

Why No Interaction Is Listed for Letrozole

Interactions in our licensed database are recorded against drug classes, not just single drug names. Letrozole is filed under 4 classifications — including aromatase inhibitors, cytochrome p450 2c19 (cyp2c19) inhibitors, cytochrome p450 3a4 (cyp3a4) substrates. Peyote has documented interactions with 1 drug class — the most serious being stimulant drugs (major) — and none of Letrozole’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

Peyote Does Interact With Other Medications

Peyote has 172 major, known drug interactions in our database — Letrozole isn’t one of them. If you take anything else, check it against the full list below.

Major 172 No known interaction 2,658 (incl. Letrozole)
Taking anything else?

Check Another of Your Medications Against Peyote

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

What to actually watch for

No Interaction Found — But Data Suggests Peyote and Letrozole 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.

  • Sweating Additional detail

    Peyote

    “Orally, ingestion of peyote can cause mild gastrointestinal effects, including nausea, vomiting, and diarrhea, within the first 30 to 60 minutes of ingestion. It can also cause mydriasis, mild tachycardia, hypertension, sweating, tremor, and visual hallucinations within about an hour after ingestion.”

    Peyote · Natural Medicines adverse-effect record, reported in anxiety.

    5 sources cited
    1. 9. Martindale W. Martindale the Extra Pharmacopoeia. Pharmaceutical Press, 1999.
    2. 17. Ellenhorn MJ, et al. Ellenhorn's Medical Toxicology: Diagnoses and Treatment of Human Poisoning. 2nd ed. Baltimore, MD: Williams & Wilkins, 1997.
    3. 68781. Lu, B. Y., Woofter, C., and Escalona, R. A case of prolonged peyote-induced psychosis resolved by sleep. J.Clin.Psychiatry 2004;65(10):1433-1434. PubMed
    4. 68789. Pelner, L. Peyote cult, mescaline hallucinations, and model psychosis. N.Y.State J.Med. 11-1-1967;67(21):2838-2843.
    5. 99284. Carstairs SD, Cantrell FL. Peyote and mescaline exposures: a 12-year review of a statewide poison center database. Clin Toxicol (Phila). 2010;48(4):350-3. PubMed

    “Orally, peyote can cause sympathomimetic effects, including mydriasis, sweating, and tremor, within approximately an hour after ingestion. Mescaline, a constituent of peyote, at doses of 20 mg/kg or greater, can cause respiratory depression and, rarely, death. Symptoms usually subside less than 24 hours after ingestion (9,17, 68775,99284).”

    Peyote · Natural Medicines adverse-effect record, reported in depression.

    Letrozole

    Listed in the ADVERSE REACTIONS section of the FDA label for Letrozole. Read the label on DailyMed ›

  • Nausea Additional detail

    Peyote

    “Orally, ingestion of peyote can cause mild gastrointestinal effects, including nausea, vomiting, and diarrhea, within the first 30 to 60 minutes of ingestion (9,17). However, a ten-year retrospective review of the California Poison Control System database suggests that vomiting and nausea following intake of peyote or peyote tea is rare.”

    Peyote · Natural Medicines adverse-effect record, reported in diarrhea.

    4 sources cited
    1. 9. Martindale W. Martindale the Extra Pharmacopoeia. Pharmaceutical Press, 1999.
    2. 17. Ellenhorn MJ, et al. Ellenhorn's Medical Toxicology: Diagnoses and Treatment of Human Poisoning. 2nd ed. Baltimore, MD: Williams & Wilkins, 1997.
    3. 99284. Carstairs SD, Cantrell FL. Peyote and mescaline exposures: a 12-year review of a statewide poison center database. Clin Toxicol (Phila). 2010;48(4):350-3. PubMed
    4. 68775. Nolte, K. B. and Zumwalt, R. E. Fatal peyote ingestion associated with Mallory-Weiss lacerations. West J.Med. 1999;170(6):328.

    Letrozole

    Listed in the ADVERSE REACTIONS section of the FDA label for Letrozole. Read the label on DailyMed ›

Reported for Peyote but not commonly for Letrozole: hallucinations, raised blood pressure, a fast or pounding heartbeat and a slow heartbeat.

Effects for Letrozole come from the ADVERSE REACTIONS section of its FDA label; effects for Peyote come from the Natural Medicines adverse-effect record, quoted above. Wording is matched across sources by our own clinical vocabulary, so treat this as a prompt to pay attention, not a diagnosis.

Special populations

Peyote in Pregnancy & Breastfeeding

Pregnancy And Lactation Unsafe

When used orally. The active constituent of peyote, mescaline, may be teratogenic.

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 Peyote 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 Peyote 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 Peyote 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 Peyote 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 Peyote
Steady interest

#1,100 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 Peyote reference on this page ↓
  • Freshness: we automatically re-check this combination every week — this pair was last verified September 13, 2026. The Peyote 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 Peyote

What is Peyote?

  • Traditional and religious ceremonies
  • Spiritual or visionary experiences
  • Folk use for pain and fatigue
  • Folk use for fever and skin conditions

Peyote is a small spineless cactus that contains mescaline, a powerful hallucinogen. It is a federally controlled substance in the United States (with a narrow exemption for certain Native American religious use), is not a safe or proven dietary supplement, and should not be used for self-treatment.

Lophophora williamsii · Cactaceae · Crown (top) of the cactus, often dried into 'buttons' · Dried buttons, chewed material, brewed tea (used ceremonially); rarely sold as a legal supplement

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

Peyote: dosing

There is no established or safe medical dose for peyote. It is not a regulated supplement, and the amount of mescaline in plant material can vary a great deal, which makes the effects unpredictable and dangerous.Because peyote is a controlled substance and a strong hallucinogen, HelloPharmacist does not provide dosing guidance.

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

Read the full Peyote 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 & Peyote

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

172Major
0Moderate
0Minor
2,657No known interaction
172 Major 2,657 No interaction
Major

172 interactions

Showing 60 of 172 major interactions — see all 172 on the Peyote page.

No interaction 2,657 drugs checked — show the list

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

Showing the 60 most looked-up of 2,657 medications checked with no known interaction — see the full Peyote list.

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

Peyote References

The 7 references that drive our Peyote 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. Martindale W. Martindale the Extra Pharmacopoeia. Pharmaceutical Press, 1999.
  2. Ellenhorn MJ, et al. Ellenhorn's Medical Toxicology: Diagnoses and Treatment of Human Poisoning. 2nd ed. Baltimore, MD: Williams & Wilkins, 1997.
  3. Gilmore HT. Petoye use during pregnancy. S D J Med 2001;54:27-9.
  4. Nolte, K. B. and Zumwalt, R. E. Fatal peyote ingestion associated with Mallory-Weiss lacerations. West J.Med. 1999;170(6):328.
  5. Lu, B. Y., Woofter, C., and Escalona, R. A case of prolonged peyote-induced psychosis resolved by sleep. J.Clin.Psychiatry 2004;65(10):1433-1434. PubMed
  6. Pelner, L. Peyote cult, mescaline hallucinations, and model psychosis. N.Y.State J.Med. 11-1-1967;67(21):2838-2843.
  7. Carstairs SD, Cantrell FL. Peyote and mescaline exposures: a 12-year review of a statewide poison center database. Clin Toxicol (Phila). 2010;48(4):350-3. 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 Peyote and Letrozole Together: Common Questions

Is it safe to take Peyote with Letrozole?
We do not list a known interaction between Peyote 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.
Do Peyote and Letrozole have any of the same side effects?
Yes — our sources link each of them separately to 2 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 Peyote and Letrozole combination checked?
Interactions in our licensed database are recorded against drug classes. Letrozole is filed under 4 classifications, and Peyote has documented interactions with 1 drug class — none of Letrozole'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 Peyote interact with any other medications?
Yes. Peyote has 172 documented drug interactions in our database — Letrozole 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 Letrozole interact with any supplements?
Yes. Letrozole has documented interactions with 142 supplements in our database — Peyote 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

Peyote 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 7 citations behind this page Ask a pharmacist Free, personal answer from our licensed team

Still Have a Question About Letrozole and Peyote?

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.