Drug & supplement interaction

Collard + Retifanlimab-Dlwr

Retifanlimab-Dlwr brand name: Zynyz.

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 Collard and Retifanlimab-Dlwr 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

Collard and Retifanlimab-Dlwr

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 Retifanlimab-Dlwr and Collard 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.

Collard safety at a glance

Collard overall Generally safe Collard is widely eaten as a food and is generally safe for most people.
Pregnancy Generally safe Normal food amounts are considered safe and nutritious during pregnancy.
Breastfeeding Generally safe Eating collard as a food is generally considered safe while breastfeeding.

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

Still wondering about combining Retifanlimab-Dlwr and Collard? Ask Dr. Brian Staiger, PharmD, BCPS directly ›
Keep it in perspective

Collard Does Interact With Other Medications

Collard has 86 moderate known drug interactions in our database — Retifanlimab-Dlwr isn’t one of them. If you take anything else, check it against the full list below.

Moderate 86 No known interaction 2,744 (incl. Retifanlimab-Dlwr)
Taking anything else?

Check Another of Your Medications Against Collard

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

What to actually watch for

What Retifanlimab-Dlwr’s Own FDA Label Lists

This is not an interaction — none of it involves Collard. These are the most notable effects listed in the ADVERSE REACTIONS section of Retifanlimab-Dlwr’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.

  • A change in thyroid levels Worth acting on
  • Blood clots Worth acting on
  • Pancreatitis Worth acting on
  • Yellowing of the skin or eyes Worth acting on
  • An irregular heartbeat Worth acting on
  • A severe skin reaction Worth acting on
  • Chest pain Worth acting on
  • A low platelet count Worth acting on
  • Kidney problems Worth acting on
  • Anemia Worth acting on

Showing the 10 most notable of 39 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 Retifanlimab-Dlwr. Read the label on DailyMed › Collard’s licensed record lists no adverse effects our clinical vocabulary could match, so there is no Collard side to compare — that is a limit of the record, not a statement that Collard has no side effects.

One more smart check

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

We hold 379 real supplement products containing Collard, each one broken down to its full ingredient list — and combination products often carry several ingredients besides Collard. Even though Collard itself has no known interaction with Retifanlimab-Dlwr, 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 Collard and Retifanlimab-Dlwr 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 Collard
Top half

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

29 days ago today
Medication Retifanlimab-Dlwr
Steady interest

#2,438 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 Collard reference on this page ↓
  • Freshness: we automatically re-check this combination every week — this pair was last verified September 20, 2026. The Collard and Retifanlimab-Dlwr records this page draws on were last updated July 3, 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 Collard

What is Collard?

  • General nutrition and vitamin source
  • Bone health
  • Heart health support
  • Digestive fiber
  • Antioxidant intake

Collard is a leafy green vegetable in the cabbage family that is rich in vitamins, minerals, and fiber, and is best thought of as a nutritious food rather than a medicine. Eating it as part of a balanced diet is healthy for most people, but there is little high-quality research on collard as a concentrated supplement. If you take blood thinners or have kidney concerns, talk with your pharmacist or doctor because of its vitamin K and oxalate content.

Brassica oleracea var. viridis · Brassicaceae · Leaves · Fresh or cooked leaves, frozen greens; occasionally powders or capsules

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

Collard: dosing

There is no established medicinal dose for collard. As a food, it can be enjoyed in normal serving sizes as part of a varied diet, just like other vegetables.If you choose a collard powder or capsule, there is no standardized dose, so follow the directions on the product label.

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

Read the full Collard monograph & all interactions
Medication

About Retifanlimab-dlwr Injection

What Is Retifanlimab-dlwr Injection Used For?

Brand name: Zynyz

Zynyz (retifanlimab-dlwr) is approved to treat two types of cancer in adults. For squamous cell carcinoma of the anal canal (SCAC), Zynyz is used in two ways: combined with chemotherapy (carboplatin and paclitaxel) as a first-line treatment for disease that cannot be surgically removed or has spread, and on its own for patients whose SCAC has progressed on or who cannot tolerate platinum-based chemotherapy.

Zynyz is also approved for metastatic or recurrent locally advanced Merkel cell carcinoma (MCC), a rare and aggressive form of skin cancer.

See full Retifanlimab-dlwr Injection drug information
Keep checking

Other Drugs & Collard

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

0Major
86Moderate
0Minor
2,743No known interaction
86 Moderate 2,743 No interaction
Moderate

86 interactions

Showing 60 of 86 moderate interactions — see all 86 on the Collard page.

No interaction 2,743 drugs checked — show the list

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

Showing the 60 most looked-up of 2,743 medications checked with no known interaction — see the full Collard list.

See the full Collard interactions page
See every supplement checked against Retifanlimab-Dlwr, ranked by severity
Evidence & sources

Collard References

The 4 references that drive our Collard 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. Zhao H, Lin J, Grossman HB, et al. Dietary isothiocyanates, GSTM1, GSTT1, NAT2 polymorphisms and bladder cancer risk. Int J Cancer 2007;120:2208-13.
  2. Cohen, J. H., Kristal, A. R., and Stanford, J. L. Fruit and vegetable intakes and prostate cancer risk. J Natl.Cancer Inst. 1-5-2000;92(1):61-68. PubMed
  3. Gaudet MM, Britton JA, Kabat GC, et al. Fruits, vegetables, and micronutrients in relation to breast cancer modified by menopause and hormone receptor status. Cancer Epidemiol Biomarkers Prev 2004;13(9):1485-94. DOI
  4. Amssayef A, Eddouks M. Antihyperglycemic Effect of the Moroccan Collard Green (Brassica oleracea var. viridis) in Streptozotocin-Induced Diabetic Rats. Endocr Metab Immune Disord Drug Targets 2020. 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 Collard and Retifanlimab-Dlwr Together: Common Questions

Is it safe to take Collard with Retifanlimab-Dlwr?
We do not list a known interaction between Collard and Retifanlimab-Dlwr. 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 Collard interact with any other medications?
Yes. Collard has 86 documented drug interactions in our database — Retifanlimab-Dlwr is simply not one of them. If you take anything else, it is worth checking each one; they are all listed on this page.

Written and reviewed by the HelloPharmacist editorial staff. Our editorial policy

Where next

Keep Exploring

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

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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.