Drug & supplement interaction

Northern Prickly Ash + 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 Northern Prickly Ash 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.

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Interaction report

Northern Prickly Ash 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 Northern Prickly Ash 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.

Northern Prickly Ash safety at a glance

Northern Prickly A... overall Use caution Limited safety data exist, so use cautiously and only short-term.
Pregnancy Possibly Unsafe When the bark is used orally; avoid using. There is insufficient reliable information available about the safety of the berry or root during pregnancy; avoid us... Read the full pregnancy detail
Breastfeeding Avoid Not enough safety information; best avoided while breastfeeding.

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 Northern Prickly Ash? 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. Northern Prickly Ash has documented interactions with 3 drug classes — the most serious being antacids (minor), h2-blockers (minor) and proton pump inhibitors (ppis) (minor) — 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

Northern Prickly Ash Does Interact With Other Medications

Northern Prickly Ash has 36 minor known drug interactions in our database — Letrozole isn’t one of them. If you take anything else, check it against the full list below.

Minor 36 No known interaction 2,794 (incl. Letrozole)
Taking anything else?

Check Another of Your Medications Against Northern Prickly Ash

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

What to actually watch for

What Letrozole’s Own FDA Label Lists

This is not an interaction — none of it involves Northern Prickly Ash. These are the most notable effects listed in the ADVERSE REACTIONS section of Letrozole’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. One of them is worth acting on rather than waiting out — marked below.

  • Bleeding or bruising Worth acting on
  • Flushing
  • Sweating
  • Joint pain
  • Muscle pain
  • Swelling
  • Tiredness
  • Dizziness
  • Headache
  • Nausea

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

Special populations

Northern Prickly Ash in Pregnancy & Breastfeeding

Pregnancy Possibly Unsafe

When the bark is used orally; avoid using. There is insufficient reliable information available about the safety of the berry or root during pregnancy; 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

From our Q&A

Questions About Northern Prickly Ash 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 Northern Prickly Ash 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 Northern Prickly Ash 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

One more smart check

Taking Northern Prickly Ash as Part of a Dietary Supplement Product? Check It for Interactions

We hold 20 real supplement products containing Northern Prickly Ash, each one broken down to its full ingredient list — and combination products often carry several ingredients besides Northern Prickly Ash. Even though Northern Prickly Ash itself has no known interaction with Letrozole, 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 Northern Prickly Ash 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 Northern Prickly Ash
Steady interest

#1,081 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 Northern Prickly Ash reference on this page ↓
  • Freshness: we automatically re-check this combination every week — this pair was last verified September 13, 2026. The Northern Prickly Ash and Letrozole 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 Northern Prickly Ash

What is Northern Prickly Ash?

Northern Prickly Ash
  • Toothache and mouth pain
  • Joint pain and rheumatism
  • Digestive upset
  • Poor circulation
  • Cramping

Northern Prickly Ash is a North American shrub whose bark and berries have a long history in folk medicine, especially for toothache, joint pain, and sluggish digestion. Modern scientific evidence for these uses is very limited, coming mostly from traditional reports and laboratory studies. Talk to your pharmacist or doctor before using it, and avoid it during pregnancy and breastfeeding.

Zanthoxylum americanum · Rutaceae · Bark and berries (fruit); sometimes leaves · Dried bark, tincture, capsules, tea, fluid extract

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

Northern Prickly Ash: dosing

There is no established standard dose for Northern Prickly Ash. Traditional preparations have varied widely, and product strengths differ between brands.If you choose to use it, follow the directions on the product label and do not exceed the suggested amount.

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

Read the full Northern Prickly Ash 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 & Northern Prickly Ash

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

0Major
0Moderate
36Minor
2,793No known interaction
36 Minor 2,793 No interaction
Minor

36 interactions

No interaction 2,793 drugs checked — show the list

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

Showing the 60 most looked-up of 2,793 medications checked with no known interaction — see the full Northern Prickly Ash list.

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

Northern Prickly Ash References

The 2 references that drive our Northern Prickly Ash 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. McGuffin M, Hobbs C, Upton R, Goldberg A, eds. American Herbal Products Association's Botanical Safety Handbook. Boca Raton, FL: CRC Press, LLC 1997.
  2. Brinker F. Herb Contraindications and Drug Interactions. 2nd ed. Sandy, OR: Eclectic Medical Publications, 1998.

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 Northern Prickly Ash and Letrozole Together: Common Questions

Is it safe to take Northern Prickly Ash with Letrozole?
We do not list a known interaction between Northern Prickly Ash 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.
How was the Northern Prickly Ash and Letrozole combination checked?
Interactions in our licensed database are recorded against drug classes. Letrozole is filed under 4 classifications, and Northern Prickly Ash has documented interactions with 3 drug classes — 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 Northern Prickly Ash interact with any other medications?
Yes. Northern Prickly Ash has 36 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 — Northern Prickly Ash 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

Northern Prickly Ash 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 2 citations behind this page Ask a pharmacist Free, personal answer from our licensed team

Still Have a Question About Letrozole and Northern Prickly Ash?

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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.