Drug & supplement interaction

American Mistletoe + Niraparib Tosylate

Niraparib Tosylate brand name: Zejula.

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 American Mistletoe and Niraparib Tosylate 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

American Mistletoe and Niraparib Tosylate

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 Niraparib Tosylate and American Mistletoe 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.

American Mistletoe safety at a glance

American Mistletoe overall Avoid American mistletoe contains toxic compounds and is not recommended for medicinal use.
Pregnancy Likely Unsafe When used orally. American mistletoe is considered an abortifacient. Read the full pregnancy detail
Breastfeeding Likely Unsafe When used orally; avoid using. 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 Niraparib Tosylate and American Mistletoe? Ask Dr. Brian Staiger, PharmD, BCPS directly ›
How we checked

Why No Interaction Is Listed for Niraparib Tosylate

Interactions in our licensed database are recorded against drug classes, not just single drug names. Niraparib Tosylate is filed under 2 classifications — p-glycoprotein substrates, oral drugs. American Mistletoe has documented interactions with 2 drug classes — the most serious being antihypertensive drugs (major) and vasodilators (major) — and none of Niraparib Tosylate’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

American Mistletoe Does Interact With Other Medications

American Mistletoe has 190 major, known drug interactions in our database — Niraparib Tosylate isn’t one of them. If you take anything else, check it against the full list below.

Major 190 No known interaction 2,640 (incl. Niraparib Tosylate)
Taking anything else?

Check Another of Your Medications Against American Mistletoe

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

What to actually watch for

No Interaction Found — But Data Suggests American Mistletoe and Niraparib Tosylate 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. One of them is worth acting on rather than waiting out — marked below.

  • Raised blood pressure Worth acting on reported in 5.9% of FDA reports for Niraparib Tosylate Additional detail

    American Mistletoe

    “Evidence on adverse effects related to American mistletoe is limited to retrospective case reviews from poison control centers. Most reports suggest that American mistletoe may be relatively well tolerated at lower doses.”

    American Mistletoe · Natural Medicines adverse-effect record, reported in cardiac arrest.

    “Orally, large doses of American mistletoe may cause bradycardia, hypertension, and cardiac arrest (6,19695).”

    American Mistletoe · Natural Medicines adverse-effect record, reported in cardiac arrest.

    2 sources cited
    1. 6. The Review of Natural Products by Facts and Comparisons. St. Louis, MO: Wolters Kluwer Co., 1999.
    2. 19695. Moore HW. Mistletoe poisoning: a review of the available literature, and the report of a case of probable fatal poisoning. J S Carolina Med Assoc 1963;59(8):269-271.

    Niraparib Tosylate

    Listed in the ADVERSE REACTIONS section of the FDA label for Niraparib Tosylate, and in voluntary FDA adverse-event reports. Read the label on DailyMed ›

  • Nausea / Diarrhea / Vomiting reported in 7.8% of FDA reports for Niraparib Tosylate Additional detail

    American Mistletoe

    “Orally, American mistletoe can cause acute gastroenteritis. Consuming large doses of American mistletoe may cause nausea, vomiting, and diarrhea. Diarrhea and vomiting from ingestion of American mistletoe can lead to dehydration, hypovolemic shock, and cardiovascular collapse (6).”

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

    1 source cited
    1. 6. The Review of Natural Products by Facts and Comparisons. St. Louis, MO: Wolters Kluwer Co., 1999.

    Niraparib Tosylate

    Listed in the ADVERSE REACTIONS section of the FDA label for Niraparib Tosylate, and in voluntary FDA adverse-event reports. Read the label on DailyMed ›

Reported for American Mistletoe but not commonly for Niraparib Tosylate: hallucinations, a slow heartbeat, dehydration and confusion.

Effects for Niraparib Tosylate come from the ADVERSE REACTIONS section of its FDA label; effects for American Mistletoe come from the Natural Medicines adverse-effect record, quoted above. Where a percentage is shown, it is the share of 51 voluntary FDA FAERS reports for Niraparib Tosylate that mention that effect — a reporting proportion, not an incidence rate and not evidence the drug caused it. Wording is matched across sources by our own clinical vocabulary, so treat this as a prompt to pay attention, not a diagnosis.

Special populations

American Mistletoe in Pregnancy & Breastfeeding

Pregnancy Likely Unsafe

When used orally. American mistletoe is considered an abortifacient.

Lactation Likely Unsafe

When used orally; 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

Everything else you take

See Every Supplement That Interacts With Niraparib Tosylate

This page covers American Mistletoe only. If you take other supplements — a multivitamin, a sleep aid, something for joints — the Niraparib Tosylate page lists 54 supplements it has a documented interaction with, worst first, each one explained.

The most serious there right now: Activated Charcoal (major), St. John's Wort (major), Bitter Melon (moderate), Black Pepper (moderate) and Bulbine Natalensis (moderate).

By severity: 2 major · 35 moderate · 17 minor.

From our pharmacist’s overview on the Niraparib Tosylate page

“Activated charcoal, popular for bloating and so-called detox routines, can trap niraparib (Zejula) in the gut before it absorbs, and St. John's wort can drive levels of the drug down another way.”

Reviewed by 2 · Jul 18, 2026

Open the Niraparib Tosylate interaction page

How much people look this up

Where American Mistletoe and Niraparib Tosylate 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 American Mistletoe
Steady interest

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

29 days ago today
Medication Niraparib Tosylate
Steady interest

#2,174 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 American Mistletoe reference on this page ↓
  • Freshness: we automatically re-check this combination every week — this pair was last verified September 20, 2026. The American Mistletoe and Niraparib Tosylate 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 American Mistletoe

What is American Mistletoe?

American Mistletoe
  • Traditional folk remedies
  • Digestive complaints
  • Decorative holiday plant

American mistletoe is a parasitic plant that is best known as a holiday decoration, not a proven medicine. It contains toxins that can harm the heart, gut, and blood vessels, and it has little reliable evidence to support any health use. We do not recommend taking it, and all parts should be kept away from children and pets.

Phoradendron leucarpum · Santalaceae · Leaves, stems, and berries · Rarely used as a supplement; historically as tea or dried plant. Most often seen as a holiday decoration.

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

American Mistletoe: dosing

There is no established safe or effective dose of American mistletoe. Because the plant is toxic and not recommended for medicinal use, no dosing guidance can be given.If you ever see a product containing mistletoe, do not take it without first speaking to a pharmacist or doctor. The safest approach is to avoid using American mistletoe internally altogether.

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

Read the full American Mistletoe monograph & all interactions
Medication

About Niraparib

What Is Niraparib Used For?

Brand name: Zejula

Zejula is used as maintenance therapy — meaning it is taken after chemotherapy to help keep the cancer from coming back — for adults with advanced epithelial ovarian, fallopian tube, or primary peritoneal cancer. For first-line maintenance, Zejula is approved for patients whose cancer is HRD-positive (has certain DNA-repair defects, including BRCA mutations or genomic instability) and who have responded to their first round of platinum-based chemotherapy.

Zejula is also approved for maintenance treatment in adults with recurrent ovarian, fallopian tube, or primary peritoneal cancer that carries a germline BRCA mutation (an inherited change in the BRCA gene), when the cancer has responded to platinum-based chemotherapy. In both cases, a companion diagnostic test is required to confirm eligibility before starting Zejula.

Most-Reported Side Effects for Niraparib Tosylate

From FAERS, the FDA’s public side-effect reporting system (51 reports, all brands). Reports are voluntary and are not proof the drug caused the effect.

Constipation 4 reports
Decreased appetite 4 reports
Fatigue 4 reports
Nausea 4 reports
Prostatic specific antigen increased 4 reports
See full Niraparib drug information
Keep checking

Other Drugs & American Mistletoe

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

190Major
0Moderate
0Minor
2,639No known interaction
190 Major 2,639 No interaction
Major

190 interactions

Showing 60 of 190 major interactions — see all 190 on the American Mistletoe page.

No interaction 2,639 drugs checked — show the list

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

Showing the 60 most looked-up of 2,639 medications checked with no known interaction — see the full American Mistletoe list.

See the full American Mistletoe interactions page
See every supplement checked against Niraparib Tosylate, ranked by severity
Evidence & sources

American Mistletoe References

The 4 references that drive our American Mistletoe 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. The Review of Natural Products by Facts and Comparisons. St. Louis, MO: Wolters Kluwer Co., 1999.
  2. Brinker F. Herb Contraindications and Drug Interactions. 2nd ed. Sandy, OR: Eclectic Medical Publications, 1998.
  3. Foster S, Tyler VE. Tyler's Honest Herbal, 4th ed., Binghamton, NY: Haworth Herbal Press, 1999. DOI
  4. Moore HW. Mistletoe poisoning: a review of the available literature, and the report of a case of probable fatal poisoning. J S Carolina Med Assoc 1963;59(8):269-271.

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 American Mistletoe and Niraparib Tosylate Together: Common Questions

Is it safe to take American Mistletoe with Niraparib Tosylate?
We do not list a known interaction between American Mistletoe and Niraparib Tosylate. 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 American Mistletoe and Niraparib Tosylate have any of the same side effects?
Yes — our sources link each of them separately to 4 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 American Mistletoe and Niraparib Tosylate combination checked?
Interactions in our licensed database are recorded against drug classes. Niraparib Tosylate is filed under 2 classifications, and American Mistletoe has documented interactions with 2 drug classes — none of Niraparib Tosylate'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 American Mistletoe interact with any other medications?
Yes. American Mistletoe has 190 documented drug interactions in our database — Niraparib Tosylate 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 Niraparib Tosylate interact with any supplements?
Yes. Niraparib Tosylate has documented interactions with 54 supplements in our database — American Mistletoe is not one of them. The Niraparib Tosylate 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

American Mistletoe monograph Uses, safety profile, and every drug interaction in one place Niraparib drug information The full plain-English guide to this medication Niraparib Tosylate supplement interactions Every supplement checked against Niraparib Tosylate, 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 4 citations behind this page Ask a pharmacist Free, personal answer from our licensed team

Still Have a Question About Niraparib Tosylate and American Mistletoe?

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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.