Drug & supplement interaction

Toothed Clubmoss + Larotrectinib

Larotrectinib brand name: Vitrakvi.

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 Toothed Clubmoss and Larotrectinib 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

Toothed Clubmoss and Larotrectinib

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 Larotrectinib and Toothed Clubmoss 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.

Toothed Clubmoss safety at a glance

Toothed Clubmoss overall Use caution May cause nervous-system and digestive side effects, and product quality varies widely.
Pregnancy Avoid Not enough safety information; avoid during pregnancy.
Breastfeeding Avoid Not enough safety information; avoid while breastfeeding.

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

Still wondering about combining Larotrectinib and Toothed Clubmoss? Ask Dr. Brian Staiger, PharmD, BCPS directly ›
How we checked

Why No Interaction Is Listed for Larotrectinib

Interactions in our licensed database are recorded against drug classes, not just single drug names. Larotrectinib is filed under 3 classifications — cytochrome p450 3a4 (cyp3a4) inhibitors, cytochrome p450 3a4 (cyp3a4) substrates, oral drugs. Toothed Clubmoss has documented interactions with 2 drug classes — the most serious being anticholinergic drugs (moderate) and cholinergic drugs (moderate) — and none of Larotrectinib’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

Toothed Clubmoss Does Interact With Other Medications

Toothed Clubmoss has 219 moderate known drug interactions in our database — Larotrectinib isn’t one of them. If you take anything else, check it against the full list below.

Moderate 219 No known interaction 2,611 (incl. Larotrectinib)
Taking anything else?

Check Another of Your Medications Against Toothed Clubmoss

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

What to actually watch for

No Interaction Found — But Data Suggests Toothed Clubmoss and Larotrectinib 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.

  • Dizziness Additional detail

    Toothed Clubmoss

    “No adverse effects have been reported. However, a thorough evaluation of safety outcomes has not been conducted.

    Orally, huperzine A, a constituent of toothed clubmoss, can cause dizziness, nausea, and sweating.”

    Toothed Clubmoss · Natural Medicines adverse-effect record, reported in nausea and vomiting.

    1 source cited
    1. 3140. Zhang RW, Tang XC, Han YY, et al. [Drug evaluation of huperzine A in the treatment of senile memory disorders]. Chung Kuo Yao Li Hsueh Pao 1991;12:250-2.

    “Orally, huperzine A, a constituent of toothed clubmoss, can cause dizziness and sweating.”

    Toothed Clubmoss · Natural Medicines adverse-effect record, reported in vertigo.

    1 source cited
    1. 3140. Zhang RW, Tang XC, Han YY, et al. [Drug evaluation of huperzine A in the treatment of senile memory disorders]. Chung Kuo Yao Li Hsueh Pao 1991;12:250-2.

    Larotrectinib

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

  • Nausea Additional detail

    Toothed Clubmoss

    “Orally, huperzine A, a constituent of toothed clubmoss, can cause nausea.”

    Toothed Clubmoss · Natural Medicines adverse-effect record, reported in nausea and vomiting.

    1 source cited
    1. 3140. Zhang RW, Tang XC, Han YY, et al. [Drug evaluation of huperzine A in the treatment of senile memory disorders]. Chung Kuo Yao Li Hsueh Pao 1991;12:250-2.

    Larotrectinib

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

Reported for Toothed Clubmoss but not commonly for Larotrectinib: sweating.

Effects for Larotrectinib come from the ADVERSE REACTIONS section of its FDA label; effects for Toothed Clubmoss 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.

Everything else you take

See Every Supplement That Interacts With Larotrectinib

This page covers Toothed Clubmoss only. If you take other supplements — a multivitamin, a sleep aid, something for joints — the Larotrectinib page lists 143 supplements it has a documented interaction with, worst first, each one explained.

The most serious there right now: Activated Charcoal (major), Grapefruit (major), St. John's Wort (major), Acacia Rigidula (moderate) and Adrafinil (moderate).

By severity: 3 major · 100 moderate · 40 minor.

From our pharmacist’s overview on the Larotrectinib page

“Nearly everything on this page interacts with larotrectinib (Vitrakvi) in one of two directions, raising or lowering how much of the drug ends up in your blood. Larotrectinib treats cancers driven by an NTRK gene fusion, and it is cleared by a liver enzyme called CYP3A4, so herbs that speed that enzyme up can drain the drug's effect wh…”

Reviewed by 2 · Jul 18, 2026

Open the Larotrectinib interaction page

One more smart check

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

We hold 101 real supplement products containing Toothed Clubmoss, each one broken down to its full ingredient list — and combination products often carry several ingredients besides Toothed Clubmoss. Even though Toothed Clubmoss itself has no known interaction with Larotrectinib, 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 Toothed Clubmoss and Larotrectinib 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 Toothed Clubmoss
Top half

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

29 days ago today
Medication Larotrectinib
Steady interest

#1,787 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 Toothed Clubmoss reference on this page ↓
  • Freshness: we automatically re-check this combination every week — this pair was last verified September 20, 2026. The Toothed Clubmoss and Larotrectinib 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 Toothed Clubmoss

What is Toothed Clubmoss?

Toothed Clubmoss
  • Memory and cognitive support
  • Alzheimer's disease and dementia
  • General brain or 'nootropic' support
  • Inflammation and pain (traditional use)
  • Age-related memory loss

Toothed Clubmoss is a moss-like plant best known as the natural source of huperzine A, a compound studied mainly for memory and Alzheimer's disease. Some early research is promising, but the evidence is limited and the supplement is not well standardized or regulated, so quality between products varies. Because it can affect the nervous system, talk with a pharmacist or doctor before using it.

Huperzia serrata · Lycopodiaceae · Whole plant (above-ground parts), the source of huperzine A · Capsules, tablets, powdered extracts; often sold as standardized 'huperzine A' supplements

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

Toothed Clubmoss: dosing

There is no official, standardized dose for Toothed Clubmoss. Most products are labeled by their huperzine A content, often in very small amounts measured in micrograms. Avoid combining different supplements that contain huperzine A.

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

Read the full Toothed Clubmoss monograph & all interactions
Medication

About Larotrectinib

What Is Larotrectinib Used For?

Brand name: Vitrakvi

Vitrakvi is used to treat adult and pediatric patients with solid tumors that have a neurotrophic receptor tyrosine kinase (NTRK) gene fusion — a specific genetic alteration that can drive tumor growth. It is used when the tumor is metastatic (has spread) or when surgery to remove it would likely cause serious harm, and when there are no satisfactory alternative treatments or the cancer has continued to grow after prior treatment.

Patients must be selected for Vitrakvi therapy based on an FDA-approved test that confirms the NTRK gene fusion in their tumor. This approval is under the FDA's accelerated approval pathway, based on how many patients responded to treatment and how long those responses lasted. Continued approval may depend on results from follow-up clinical trials.

See full Larotrectinib drug information
Keep checking

Other Drugs & Toothed Clubmoss

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

0Major
219Moderate
0Minor
2,610No known interaction
219 Moderate 2,610 No interaction
Moderate

219 interactions

Showing 60 of 219 moderate interactions — see all 219 on the Toothed Clubmoss page.

No interaction 2,610 drugs checked — show the list

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

Showing the 60 most looked-up of 2,610 medications checked with no known interaction — see the full Toothed Clubmoss list.

See the full Toothed Clubmoss interactions page
See every supplement checked against Larotrectinib, ranked by severity
Evidence & sources

Toothed Clubmoss References

The 3 references that drive our Toothed Clubmoss 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. Budavari S, ed. The Merck Index. 12th ed. Whitehouse Station, NJ: Merck & Co., Inc., 1996.
  2. Zhang RW, Tang XC, Han YY, et al. [Drug evaluation of huperzine A in the treatment of senile memory disorders]. Chung Kuo Yao Li Hsueh Pao 1991;12:250-2.
  3. Ohba T, Yoshino Y, Ishisaka M, et al. Japanese Huperzia serrata extract and the constituent, huperzine A, ameliorate the scopolamine-induced cognitive impairment in mice. Biosci Biotechnol Biochem. 2015;79(11):1838-44.

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 Toothed Clubmoss and Larotrectinib Together: Common Questions

Is it safe to take Toothed Clubmoss with Larotrectinib?
We do not list a known interaction between Toothed Clubmoss and Larotrectinib. 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 Toothed Clubmoss and Larotrectinib 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.
How was the Toothed Clubmoss and Larotrectinib combination checked?
Interactions in our licensed database are recorded against drug classes. Larotrectinib is filed under 3 classifications, and Toothed Clubmoss has documented interactions with 2 drug classes — none of Larotrectinib'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 Toothed Clubmoss interact with any other medications?
Yes. Toothed Clubmoss has 219 documented drug interactions in our database — Larotrectinib 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 Larotrectinib interact with any supplements?
Yes. Larotrectinib has documented interactions with 143 supplements in our database — Toothed Clubmoss is not one of them. The Larotrectinib 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

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

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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.