Drug & supplement interaction

Pantothenic Acid + Letrozole

Letrozole brand name: Femara.

No Known Interaction
The bottom line No known interaction

We found no known interaction between Pantothenic Acid 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

Pantothenic Acid 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 Pantothenic Acid 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 Pantothenic Acid 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.

Pantothenic Acid safety at a glance

Pantothenic Acid overall Generally safe Considered safe for most people at typical supplement doses, with few side effects.
Pregnancy Likely Safe When used orally and appropriately. The daily adequate intake (AI) during pregnancy is 6 mg. Read the full pregnancy detail
Breastfeeding Likely Safe When used orally and appropriately. The daily adequate intake (AI) during lactation is 7 mg. 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 Pantothenic Acid? Ask Dr. Brian Staiger, PharmD, BCPS directly ›
What to actually watch for

What Pantothenic Acid Itself Has Been Linked To

This is not an interaction — nothing below involves Letrozole. It is the side-effect record for Pantothenic Acid on its own, from the licensed Natural Medicines monograph. If something new turns up after you add Pantothenic Acid, this list is the first place to look.

  • Itching / A skin rash Additional detail

    “Topically, dexpanthenol has been associated with itching, burning, skin irritation, contact dermatitis, and eczema. Three cases of allergic contact dermatitis have been reported.”

    Pantothenic Acid · Natural Medicines adverse-effect record, reported in dermatitis.

    6 sources cited
    1. 67779. Schmuth, M., Wimmer, M. A., Hofer, S., Sztankay, A., Weinlich, G., Linder, D. M., Elias, P. M., Fritsch, P. O., and Fritsch, E. Topical corticosteroid therapy for acute radiation dermatitis: a prospective, randomized, double-blind study. Br.J.Dermatol. 2 PubMed
    2. 67781. Schreck, U., Paulsen, F., Bamberg, M., and Budach, W. Intraindividual comparison of two different skin care conceptions in patients undergoing radiotherapy of the head-and-neck region. Creme or powder? Strahlenther.Onkol. 2002;178(6):321-329. PubMed
    3. 67788. Herbst, R. A., Uter, W., Pirker, C., Geier, J., and Frosch, P. J. Allergic and non-allergic periorbital dermatitis: patch test results of the Information Network of the Departments of Dermatology during a 5-year period. Contact Dermatitis 2004;51(1):13-1 PubMed
    4. 111258. Scott LN, Fiume M, Bergfeld WF, et al. Safety Assessment of Panthenol, Pantothenic Acid, and Derivatives as Used in Cosmetics. Int J Toxicol 2022;41(3_suppl):77-128. PubMed
    5. 111262. Peltier E, Trapp S, de Salvo R, et al. A new dexpanthenol-containing liquid cleanser for atopic-prone skin: Results from two prospective clinical studies evaluating cutaneous tolerability, moisturization potential, and effects on barrier function. J Cosme PubMed
    6. 111260. Han J, Warshaw EM. Allergic Contact Dermatitis to Panthenol in "Hypoallergenic" Products. Dermatitis 2023;34(1):62-63. PubMed
  • Diarrhea Additional detail

    “Orally, pantothenic acid has been associated with diarrhea.”

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

    2 sources cited
    1. 67822. Champault, G. and Patel, J. C. [Treatment of constipation with Bepanthene]. Med.Chir Dig. 1977;6(1):57-59.
    2. 111258. Scott LN, Fiume M, Bergfeld WF, et al. Safety Assessment of Panthenol, Pantothenic Acid, and Derivatives as Used in Cosmetics. Int J Toxicol 2022;41(3_suppl):77-128. PubMed

Everything above comes from the Natural Medicines adverse-effect record for Pantothenic Acid — 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

Pantothenic Acid in Pregnancy & Breastfeeding

Pregnancy Likely Safe

When used orally and appropriately. The daily adequate intake (AI) during pregnancy is 6 mg.

Lactation Likely Safe

When used orally and appropriately. The daily adequate intake (AI) during lactation is 7 mg.

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 Pantothenic Acid 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 Pantothenic Acid 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 Pantothenic Acid 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 Pantothenic Acid as Part of a Dietary Supplement Product? Check It for Interactions

We hold 15,997 real supplement products containing Pantothenic Acid, each one broken down to its full ingredient list — and combination products often carry several ingredients besides Pantothenic Acid. Even though Pantothenic Acid 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 Pantothenic Acid 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 Pantothenic Acid
Top 5%

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

What is Pantothenic Acid?

  • General nutrition and energy
  • Skin and hair health
  • Acne (topical and oral)
  • Wound healing (as panthenol)
  • Cholesterol support (as pantethine)

Pantothenic acid is vitamin B5, an essential nutrient your body uses to turn food into energy. True deficiency is very rare because it is found in nearly all foods, and most people meet their needs through diet. Supplements are generally considered safe, but evidence that extra amounts treat acne, high cholesterol, or other conditions is limited.

Tablets, capsules, softgels, multivitamins, topical creams (as panthenol)

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

Pantothenic Acid: dosing

There is no single standardized "treatment" dose of pantothenic acid for most uses. Nutrition authorities set general daily intake amounts for adults to prevent deficiency, and most people easily get this from food.Supplement products vary widely in how much they contain, with some marketed for acne or other uses providing amounts far above dietary needs. Do not assume more is better.

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

Read the full Pantothenic Acid 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 & Pantothenic Acid

Browse every other medication we’ve checked against Pantothenic Acid — 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
No interaction 2,829 drugs checked — show the list
Evidence & sources

Pantothenic Acid References

The 11 references that drive our Pantothenic Acid 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. McEvoy GK, ed. AHFS Drug Information. Bethesda, MD: American Society of Health-System Pharmacists, 1998.
  2. Yates AA, Schlicker SA, Suitor CW. Dietary reference intakes: The new basis for recommendations for calcium and related nutrients, B vitamins, and choline. J Am Diet Assoc 1998;98:699-706. PubMed
  3. Debourdeau PM, Djezzar S, Estival JL, et al. Life-threatening eosinophilic pleuropericardial effusion related to vitamins B5 and H. Ann Pharmacother 2001;35:424-6. DOI
  4. Schmuth, M., Wimmer, M. A., Hofer, S., Sztankay, A., Weinlich, G., Linder, D. M., Elias, P. M., Fritsch, P. O., and Fritsch, E. Topical corticosteroid therapy for acute radiation dermatitis: a prospective, randomized, double-blind study. Br.J.Dermatol. 2 PubMed
  5. Schreck, U., Paulsen, F., Bamberg, M., and Budach, W. Intraindividual comparison of two different skin care conceptions in patients undergoing radiotherapy of the head-and-neck region. Creme or powder? Strahlenther.Onkol. 2002;178(6):321-329. PubMed
  6. Herbst, R. A., Uter, W., Pirker, C., Geier, J., and Frosch, P. J. Allergic and non-allergic periorbital dermatitis: patch test results of the Information Network of the Departments of Dermatology during a 5-year period. Contact Dermatitis 2004;51(1):13-1 PubMed
  7. Champault, G. and Patel, J. C. [Treatment of constipation with Bepanthene]. Med.Chir Dig. 1977;6(1):57-59.
  8. Scott LN, Fiume M, Bergfeld WF, et al. Safety Assessment of Panthenol, Pantothenic Acid, and Derivatives as Used in Cosmetics. Int J Toxicol 2022;41(3_suppl):77-128. PubMed
  9. Han J, Warshaw EM. Allergic Contact Dermatitis to Panthenol in "Hypoallergenic" Products. Dermatitis 2023;34(1):62-63. PubMed
  10. Blanchard G, Kerre S, Walker A, et al. Allergic contact dermatitis from pantolactone and dexpanthenol in wound healing creams. Contact Dermatitis 2022;87(5):468-471. PubMed
  11. Peltier E, Trapp S, de Salvo R, et al. A new dexpanthenol-containing liquid cleanser for atopic-prone skin: Results from two prospective clinical studies evaluating cutaneous tolerability, moisturization potential, and effects on barrier function. J Cosme 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 Pantothenic Acid and Letrozole Together: Common Questions

Is it safe to take Pantothenic Acid with Letrozole?
We do not list a known interaction between Pantothenic Acid 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 — Pantothenic Acid 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

Still Have a Question About Letrozole and Pantothenic Acid?

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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.