Drug & supplement interaction

Purple Loosestrife + Pemetrexed

Pemetrexed brand names: Alimta, Pemfexy.

No Known Interaction
Medically reviewed by · Updated June 2026 · Pair last verified Sep 20, 2026
The bottom line No known interaction

We found no known interaction between Purple Loosestrife and Pemetrexed 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

Purple Loosestrife and Pemetrexed

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 Pemetrexed and Purple Loosestrife 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 Purple Loosestrife at all — not against Pemetrexed, 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.

Purple Loosestrife safety at a glance

Purple Loosestrife overall Use caution Generally used in folk medicine, but human safety data are limited.
Pregnancy Avoid Not enough safety information, so it is best avoided.
Breastfeeding Avoid No reliable safety data, so avoid while breastfeeding.

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

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

What Pemetrexed’s Own FDA Label Lists

This is not an interaction — none of it involves Purple Loosestrife. These are the most notable effects listed in the ADVERSE REACTIONS section of Pemetrexed’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. 10 of them are worth acting on rather than waiting out — marked below.

  • High potassium Worth acting on
  • Low sodium Worth acting on
  • Low potassium Worth acting on
  • High blood sugar Worth acting on
  • A low platelet count Worth acting on
  • Kidney problems Worth acting on
  • Anemia Worth acting on
  • Shortness of breath Worth acting on
  • A low white blood cell count Worth acting on
  • A higher chance of infection Worth acting on

Showing the 10 most notable of 22 label-listed effects — ranked by how unusual each one is across medicines generally, with serious effects weighted up.

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

Everything else you take

See Every Supplement That Interacts With Pemetrexed

This page covers Purple Loosestrife only. If you take other supplements — a multivitamin, a sleep aid, something for joints — the Pemetrexed page lists 4 supplements it has a documented interaction with, worst first, each one explained.

The most serious there right now: African Wild Potato (moderate), Banderol (moderate), Caffeic Acid (moderate) and Quercetin (moderate).

By severity: 4 moderate.

From our pharmacist’s overview on the Pemetrexed page

“Every supplement on file for pemetrexed (Alimta, Pemfexy) works the same way. Each can slow how the kidneys pull the drug out of the blood, which would let it linger and build to higher levels than intended.”

Reviewed by 2 · Jul 18, 2026

Open the Pemetrexed interaction page

One more smart check

Taking Purple Loosestrife as Part of a Dietary Supplement Product? Check It for Interactions

We hold 26 real supplement products containing Purple Loosestrife, each one broken down to its full ingredient list — and combination products often carry several ingredients besides Purple Loosestrife. Even though Purple Loosestrife itself has no known interaction with Pemetrexed, 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 Purple Loosestrife and Pemetrexed 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 Purple Loosestrife
Top half

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

29 days ago today
Medication Pemetrexed
Top half

#1,332 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.
  • Freshness: we automatically re-check this combination every week — this pair was last verified September 20, 2026. The Purple Loosestrife and Pemetrexed records this page draws on were last updated June 22, 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 Purple Loosestrife

What is Purple Loosestrife?

  • Diarrhea
  • Digestive upset
  • Minor wound care
  • Sore throat and mouth irritation
  • Menstrual-related complaints

Purple Loosestrife is a flowering wetland plant traditionally used for diarrhea and minor digestive or skin complaints, largely because of its astringent tannin content. Modern human studies are very limited, so its benefits are not well proven. If you are considering it, talk with your pharmacist or doctor first, and avoid it during pregnancy and breastfeeding.

Lythrum salicaria · Lythraceae · Aerial parts (flowering tops, leaves) · Tea, liquid extract, tincture, dried herb

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

Purple Loosestrife: dosing

There is no well-established standardized dose for Purple Loosestrife. Traditional use has involved teas and liquid extracts, but reliable dosing guidelines from clinical research are not available.If you choose to use a commercial product, follow the directions on the label and do not exceed them.

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

Read the full Purple Loosestrife monograph & all interactions
Medication

About Pemetrexed Injection

What Is Pemetrexed Injection Used For?

Brand names: Alimta, Pemfexy

Pemetrexed Injection is used for non-squamous non-small cell lung cancer (NSCLC) in several situations: as an initial treatment (combined with pembrolizumab and platinum chemotherapy, or with cisplatin alone), as a maintenance treatment after platinum-based chemotherapy, or as a single agent when the cancer has come back after prior chemotherapy. It is not used for squamous cell non-small cell lung cancer.

Pemetrexed Injection is also used, in combination with cisplatin, for the initial treatment of malignant pleural mesothelioma — a cancer of the lining of the lungs — in patients whose disease cannot be surgically removed or who are not good candidates for surgery.

Most-Reported Side Effects for Pemetrexed

From FAERS, the FDA’s public side-effect reporting system (37,889 reports, all brands). Reports are voluntary and are not proof the drug caused the effect.

Malignant neoplasm progression 3,095 reports
Anemia 2,134 reports
Nausea 1,906 reports
Diarrhea 1,824 reports
Pancytopenia 1,773 reports
See full Pemetrexed Injection drug information
Keep checking

Other Drugs & Purple Loosestrife

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

See the full Purple Loosestrife interactions page
See every supplement checked against Pemetrexed, ranked by severity
Sources

Sources & How We Checked

We checked Purple Loosestrife against Pemetrexed in the Natural Medicines interaction database and found no documented interaction on file. The medication overview comes from MedlinePlus, and supplement label details from the NIH Dietary Supplement Label Database.

Content is written and reviewed by licensed HelloPharmacist pharmacists. See our data sources and editorial standards for how this information is built and checked.

Parts of this content are provided by the Therapeutic Research Center, LLC.

DISCLAIMER: Currently this does not check for drug-drug interactions. This is not an all-inclusive comprehensive list of potential interactions and is for informational purposes only. Not all interactions are known or well-reported in the scientific literature, and new interactions are continually being reported. Input is needed from a qualified healthcare provider including a pharmacist before starting any therapy. Application of clinical judgment is necessary.

© 2021 Therapeutic Research Center, LLC

Keep exploring
Purple Loosestrife monograph › Uses, safety, and every drug interaction in one place Pemetrexed supplement interactions › Every supplement checked against Pemetrexed, ranked by severity Pemetrexed Injection drug information › The full plain-English guide to this medication Supplement interaction checker › Check any supplement or product against your medications Browse medications A–Z › Every drug we've checked against herbs & supplements Ask a pharmacist › Free, personal answer from our licensed team
Pharmacist Counseling Corner

Taking Purple Loosestrife and Pemetrexed Together: Common Questions

Is it safe to take Purple Loosestrife with Pemetrexed?
We do not list a known interaction between Purple Loosestrife and Pemetrexed. 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 Pemetrexed interact with any supplements?
Yes. Pemetrexed has documented interactions with 4 supplements in our database — Purple Loosestrife is not one of them. The Pemetrexed 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 Pemetrexed and Purple Loosestrife?

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.