Drug & supplement interaction

Pyrethrum + Alosetron

Alosetron brand name: Lotronex.

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 Pyrethrum and Alosetron 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

Pyrethrum and Alosetron

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 Alosetron and Pyrethrum 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 Pyrethrum at all — not against Alosetron, 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.

Pyrethrum safety at a glance

Pyrethrum overall Use caution Pyrethrum is an insecticide, not a dietary supplement, and should not be taken internally.
Pregnancy Avoid Avoid internal use and limit exposure to insecticide products during pregnancy due to lack of safety data.
Breastfeeding Avoid Avoid internal use while breastfeeding because safety has not been established.

Safety guidance is general; always confirm with your pharmacist or doctor for your situation.

Still wondering about combining Alosetron and Pyrethrum? Ask Dr. Brian Staiger, PharmD, BCPS directly ›
What to actually watch for

No Interaction Found — But Data Suggests Pyrethrum and Alosetron 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.

  • Headache / Nausea Additional detail

    Pyrethrum

    “Pyrethrum has limited toxicity. The symptoms of overdose include headache, tinnitus, nausea, tingling of fingers and toes, respiratory disturbances, and other symptoms of neurotoxicity (18). The pyrethrum flower or derivatives of it might cause an allergic reaction in individuals sensitive to the Asteraceae/Compositae family.”

    Pyrethrum · Natural Medicines adverse-effect record, reported in cluster headache.

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

    Alosetron

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

Reported for Pyrethrum but not commonly for Alosetron: an allergic reaction, numbness or tingling and ringing in the ears.

Effects for Alosetron come from the ADVERSE REACTIONS section of its FDA label; effects for Pyrethrum 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.

From our Q&A

Questions About Pyrethrum or Alosetron

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

This page covers Pyrethrum only. If you take other supplements — a multivitamin, a sleep aid, something for joints — the Alosetron page lists 38 supplements it has a documented interaction with, worst first, each one explained.

The most serious there right now: Activated Charcoal (major), Lithium (major), 5-htp (moderate), Acetyl-l-carnitine (moderate) and Ayahuasca (moderate).

By severity: 2 major · 25 moderate · 11 minor.

From our pharmacist’s overview on the Alosetron page

“Alosetron (Lotronex) treats severe diarrhea-predominant IBS by acting on serotonin receptors in the gut, and that is where most of its 38 supplement interactions come from. Twenty of the ingredients, 5-HTP among them, raise serotonin on their own, and stacking them on a serotonin-acting drug is a combination I want you to treat with re…”

Reviewed by 2 · Jul 18, 2026

Open the Alosetron interaction page

How much people look this up

Where Pyrethrum and Alosetron 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 Pyrethrum
Top half

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

29 days ago today
Medication Alosetron
Steady interest

#2,146 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 Pyrethrum reference on this page ↓
  • Freshness: we automatically re-check this combination every week — this pair was last verified September 20, 2026. The Pyrethrum and Alosetron 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 Pyrethrum

What is Pyrethrum?

  • Natural insect repellent
  • Killing fleas, lice, and other pests
  • Garden and household insecticide
  • Traditional use against parasites

Pyrethrum is a daisy-like flower whose extracts (called pyrethrins) are widely used as a natural insecticide for plants, pets, and lice. It is not a supplement meant to be taken by mouth, and there is no good evidence supporting any internal health use. If you use pyrethrum products, treat them as pesticides and follow label directions carefully.

Tanacetum cinerariifolium · Asteraceae · Dried flower heads · Insecticide powders, sprays, and extracts (pyrethrins); rarely used internally

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

Pyrethrum: dosing

There is no established or recommended internal dose for pyrethrum, and it should not be taken as a supplement. For insecticide, lice, or flea products, the correct amount depends entirely on the specific product.Always follow the directions on the product label exactly, and do not use more or more often than directed.

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

Read the full Pyrethrum monograph & all interactions
Medication

About Alosetron

What Is Alosetron Used For?

Brand name: Lotronex

Alosetron tablets — available as Alosetron, Alosetron Hydrochloride, and Lotronex — are approved only for women with severe diarrhea-predominant irritable bowel syndrome (IBS) whose symptoms have lasted 6 months or longer and who have not gotten adequate relief from conventional therapy. Other causes of GI symptoms must be ruled out first.

To qualify as severe, diarrhea-predominant IBS must include diarrhea plus at least one of the following: frequent and severe abdominal pain or discomfort, frequent bowel urgency or fecal incontinence (accidental stool leakage), or significant disruption to daily activities. Clinical studies have not confirmed the same benefit in men.

See full Alosetron drug information
Keep checking

Other Drugs & Pyrethrum

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

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

Pyrethrum References

The 3 references that drive our Pyrethrum 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. Covington TR, et al. Handbook of Nonprescription Drugs. 11th ed. Washington, DC: American Pharmaceutical Association, 1996.
  3. Drugs in Pregnancy and Lactation. 4th ed. Baltimore, MD: Williams & Wilkins, 1994.

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 Pyrethrum and Alosetron Together: Common Questions

Is it safe to take Pyrethrum with Alosetron?
We do not list a known interaction between Pyrethrum and Alosetron. 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 Pyrethrum and Alosetron 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.
Does Alosetron interact with any supplements?
Yes. Alosetron has documented interactions with 38 supplements in our database — Pyrethrum is not one of them. The Alosetron 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

Pyrethrum monograph Uses, safety profile, and every drug interaction in one place Alosetron drug information The full plain-English guide to this medication Alosetron supplement interactions Every supplement checked against Alosetron, 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 Alosetron and Pyrethrum?

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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.