Drug & supplement interaction

Cudweed + Nafcillin

Nafcillin brand name: Nallpen.

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 Cudweed and Nafcillin 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

Cudweed and Nafcillin

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 Nafcillin and Cudweed 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.

Cudweed safety at a glance

Cudweed overall Not established Limited modern safety data exist, so use with caution and talk to a healthcare provider first.
Pregnancy Avoid Not enough safety information is available, so avoid use during pregnancy.
Breastfeeding Avoid There is no reliable safety data, so avoid use while breastfeeding.

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

Still wondering about combining Nafcillin and Cudweed? Ask Dr. Brian Staiger, PharmD, BCPS directly ›
How we checked

Why No Interaction Is Listed for Nafcillin

Interactions in our licensed database are recorded against drug classes, not just single drug names. Nafcillin is filed under 4 classifications — including cytochrome p450 3a4 (cyp3a4) inducers, antibiotic drugs, nephrotoxic drugs. Cudweed has documented interactions with 1 drug class — the most serious being antidiabetes drugs (moderate) — and none of Nafcillin’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

Cudweed Does Interact With Other Medications

Cudweed has 86 moderate known drug interactions in our database — Nafcillin 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. Nafcillin)
Taking anything else?

Check Another of Your Medications Against Cudweed

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

What to actually watch for

What Nafcillin’s Own FDA Label Lists

This is not an interaction — none of it involves Cudweed. These are the most notable effects listed in the ADVERSE REACTIONS section of Nafcillin’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. 7 of them are worth acting on rather than waiting out — marked below.

  • Kidney problems Worth acting on mentioned in 21.2% of FDA reports for Nafcillin
  • Blood clots Worth acting on
  • Wheezing Worth acting on
  • A severe allergic reaction Worth acting on
  • Hives Worth acting on
  • A low white blood cell count Worth acting on
  • An allergic reaction Worth acting on
  • Mouth irritation or sores
  • Fever mentioned in 4.8% of FDA reports for Nafcillin
  • Low blood pressure

Showing the 10 most notable of 20 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 Nafcillin. Read the label on DailyMed › Where a percentage is shown, it is the share of 918 voluntary FDA FAERS reports for Nafcillin that mention that effect — a reporting proportion, not an incidence rate and not evidence the drug caused it. Cudweed’s licensed record lists no adverse effects our clinical vocabulary could match, so there is no Cudweed side to compare — that is a limit of the record, not a statement that Cudweed has no side effects.

Everything else you take

See Every Supplement That Interacts With Nafcillin

This page covers Cudweed only. If you take other supplements — a multivitamin, a sleep aid, something for joints — the Nafcillin page lists 58 supplements it has a documented interaction with, worst first, each one explained.

The most serious there right now: Asarabacca (major), Siberian Cocklebur (major), Alkanna (moderate), Alpine Ragwort (moderate) and Aristolochia (moderate).

By severity: 2 major · 54 moderate · 2 minor.

From our pharmacist’s overview on the Nafcillin page

“Anyone on nafcillin (Nallpen) is usually fighting a serious staph infection, and that makes this a time to be genuinely careful with supplements. Of the 58 with a known interaction on file, the two rated major, Siberian cocklebur and asarabacca, both stress the kidneys and could compound damage while you are being treated.”

Reviewed by 2 · Jul 18, 2026

Open the Nafcillin interaction page

How much people look this up

Where Cudweed and Nafcillin 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 Cudweed
Top half

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

29 days ago today
Medication Nafcillin
Steady interest

#2,647 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 Cudweed reference on this page ↓
  • Freshness: we automatically re-check this combination every week — this pair was last verified September 20, 2026. The Cudweed and Nafcillin records this page draws on were last updated June 20, 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 Cudweed

What is Cudweed?

  • Mouth and throat irritation
  • Digestive upset
  • Mild high blood pressure (traditional)
  • Minor wounds and skin irritation
  • Coughs and respiratory complaints

Cudweed is a small, woolly-leaved plant used in traditional herbal medicine, mainly as a tea or gargle for sore throats, digestive upset, and minor skin problems. There is very little modern scientific evidence to confirm that it works for any condition, and safety data are limited, so it is best used cautiously and avoided in pregnancy and breastfeeding.

Gnaphalium uliginosum · Asteraceae · Aerial parts (flowering tops, leaves, and stems) · Tea (infusion), tincture, dried herb

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

Cudweed: dosing

There is no established or standardized dose for cudweed. It has not been studied enough to know a safe and effective amount, and traditional preparations vary.If you choose to use a commercial product, follow the directions on the label and do not exceed the recommended amount.

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

Read the full Cudweed monograph & all interactions
Medication

About Nafcillin Injection

What Is Nafcillin Injection Used For?

Brand name: Nallpen

NAFCILLIN Injection is used to treat infections caused by staphylococci — specifically strains that produce an enzyme called penicillinase, which makes them resistant to regular penicillin. Susceptibility testing is performed to confirm the bacteria will respond to nafcillin before or shortly after starting treatment.

Nafcillin may also be started right away when a resistant staph infection is strongly suspected, even before test results are available. It should not be used for infections caused by bacteria that would respond to standard penicillin G, or for infections caused by non-staph organisms.

Most-Reported Side Effects for Nafcillin

From FAERS, the FDA’s public side-effect reporting system (918 reports, all brands). Reports are voluntary and are not proof the drug caused the effect.

Renal failure acute 64 reports
Rash 56 reports
Acute kidney injury 49 reports
Fever 44 reports
Tubulointerstitial nephritis 43 reports
See full Nafcillin Injection drug information
Keep checking

Other Drugs & Cudweed

Browse every other medication we’ve checked against Cudweed — 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 Cudweed page.

No interaction 2,743 drugs checked — show the list

We also checked Cudweed 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 Cudweed list.

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

Cudweed References

The 1 references that drive our Cudweed 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. Shikov AN, Pozharitskaya ON, Makarov VG, et al. Medicinal plants of the Russian Pharmacopoeia; their history and applications. J Ethnopharmacol 2014;154(3):481-536. 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 Cudweed and Nafcillin Together: Common Questions

Is it safe to take Cudweed with Nafcillin?
We do not list a known interaction between Cudweed and Nafcillin. 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.
How was the Cudweed and Nafcillin combination checked?
Interactions in our licensed database are recorded against drug classes. Nafcillin is filed under 4 classifications, and Cudweed has documented interactions with 1 drug class — none of Nafcillin'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 Cudweed interact with any other medications?
Yes. Cudweed has 86 documented drug interactions in our database — Nafcillin 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 Nafcillin interact with any supplements?
Yes. Nafcillin has documented interactions with 58 supplements in our database — Cudweed is not one of them. The Nafcillin 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

Cudweed monograph Uses, safety profile, and every drug interaction in one place Nafcillin Injection drug information The full plain-English guide to this medication Nafcillin supplement interactions Every supplement checked against Nafcillin, 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 1 citations behind this page Ask a pharmacist Free, personal answer from our licensed team

Still Have a Question About Nafcillin and Cudweed?

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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.