Drug & supplement interaction

Cereus + Flecainide

Flecainide brand name: Tambocor.

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 Cereus and Flecainide 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

Cereus and Flecainide

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 Flecainide and Cereus 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.

Cereus safety at a glance

Cereus overall Use caution Limited safety data and possible effects on the heart make professional guidance important.
Pregnancy Avoid Not enough safety information; avoid during pregnancy.
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 Flecainide and Cereus? Ask Dr. Brian Staiger, PharmD, BCPS directly ›
How we checked

Why No Interaction Is Listed for Flecainide

Interactions in our licensed database are recorded against drug classes, not just single drug names. Flecainide is filed under 4 classifications — including qt interval-prolonging drugs, cytochrome p450 2d6 (cyp2d6) substrates, oral drugs. Cereus has documented interactions with 2 drug classes — the most serious being digoxin (lanoxin) (moderate) and monoamine oxidase inhibitors (maois) (moderate) — and none of Flecainide’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

Cereus Does Interact With Other Medications

Cereus has 10 moderate known drug interactions in our database — Flecainide isn’t one of them. If you take anything else, check it against the full list below.

Moderate 10 No known interaction 2,820 (incl. Flecainide)
Taking anything else?

Check Another of Your Medications Against Cereus

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

What to actually watch for

No Interaction Found — But Data Suggests Cereus and Flecainide 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.

  • Itching / Diarrhea / Vomiting / Nausea Additional detail

    Cereus

    “Orally, fresh cereus juice may cause burning of the mouth, queasiness, nausea, vomiting, and diarrhea (4,18).

    Topically, it may cause itching and skin pustules (18).”

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

    2 sources cited
    1. 4. Newall CA, Anderson LA, Philpson JD. Herbal Medicine: A Guide for Healthcare Professionals. London, UK: The Pharmaceutical Press, 1996.
    2. 18. Gruenwald J, Brendler T, Jaenicke C. PDR for Herbal Medicines. 1st ed. Montvale, NJ: Medical Economics Company, Inc., 1998.

    Flecainide

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

Effects for Flecainide come from the ADVERSE REACTIONS section of its FDA label; effects for Cereus 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.

From our Q&A

Questions About Cereus or Flecainide

These are real questions from readers, answered by the pharmacists at HelloPharmacist — written by a person, not generated from a database. Each one covers Cereus or Flecainide, not necessarily both, but if one is close to what you were about to ask it will usually go further than a database entry can:

Not quite your question? Ask our pharmacists directly — it is free, there is no account required, and answers usually come back within 24 hours.

Everything else you take

See Every Supplement That Interacts With Flecainide

This page covers Cereus only. If you take other supplements — a multivitamin, a sleep aid, something for joints — the Flecainide page lists 86 supplements it has a documented interaction with, worst first, each one explained.

The most serious there right now: Activated Charcoal (major), American Hellebore (major), Arsenic (major), Cesium (major) and Ephedra (major).

By severity: 7 major · 61 moderate · 18 minor.

From our pharmacist’s overview on the Flecainide page

“Flecainide (Tambocor) exists to control serious heart rhythm problems, so anything that disturbs the rhythm it protects deserves genuine caution. Six of the seven major-rated entries among the 86 supplements and herbs on file, grapefruit in large amounts included, can prolong the QT interval, the heart's electrical reset time, adding t…”

Reviewed by 2 · Jul 18, 2026

Open the Flecainide interaction page

One more smart check

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

We hold 3 real supplement products containing Cereus, each one broken down to its full ingredient list — and combination products often carry several ingredients besides Cereus. Even though Cereus itself has no known interaction with Flecainide, 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 Cereus and Flecainide 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 Cereus
Steady interest

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

29 days ago today
Medication Flecainide
Top 25%

#631 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 Cereus reference on this page ↓
  • Freshness: we automatically re-check this combination every week — this pair was last verified September 20, 2026. The Cereus and Flecainide 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 Cereus

What is Cereus?

  • Heart palpitations
  • Mild heart symptoms
  • Anxiety and nervous tension
  • Shortness of breath
  • Fluid retention

Cereus (often called night-blooming cereus) is a cactus traditionally used in folk and homeopathic medicine for heart-related complaints like palpitations. High-quality human evidence supporting these uses is lacking, and because it may affect the heart, it should be used only under medical guidance. Pregnant and breastfeeding people should avoid it.

Selenicereus grandiflorus · Cactaceae · Flowers and young stems · Tincture, liquid extract, capsules, homeopathic preparations

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

Cereus: dosing

There is no established standard dose of Cereus. Products vary widely in strength, and homeopathic preparations are very different from herbal tinctures.If you choose to use a Cereus product, follow the directions on the label and do not exceed them.

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

Read the full Cereus monograph & all interactions
Medication

About Flecainide

What Is Flecainide Used For?

Brand name: Tambocor

Flecainide Acetate tablets are used to prevent episodes of certain abnormal heart rhythms. In patients without structural heart disease, it is approved to prevent paroxysmal supraventricular tachycardia (PSVT — episodes of rapid heart rate starting above the ventricles) and paroxysmal atrial fibrillation/flutter (PAF — intermittent episodes of irregular, rapid heart rhythm in the upper chambers), when these cause disabling symptoms.

Flecainide Acetate tablets are also used to prevent life-threatening ventricular arrhythmias — dangerous rapid rhythms starting in the lower chambers of the heart, such as sustained ventricular tachycardia. It is not recommended for less serious ventricular arrhythmias, for patients with a recent heart attack, or for chronic (ongoing, persistent) atrial fibrillation.

See full Flecainide drug information
Keep checking

Other Drugs & Cereus

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

0Major
10Moderate
0Minor
2,819No known interaction
10 Moderate 2,819 No interaction
Moderate

10 interactions

No interaction 2,819 drugs checked — show the list

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

Showing the 60 most looked-up of 2,819 medications checked with no known interaction — see the full Cereus list.

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

Cereus References

The 3 references that drive our Cereus 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. Newall CA, Anderson LA, Philpson JD. Herbal Medicine: A Guide for Healthcare Professionals. London, UK: The Pharmaceutical Press, 1996.
  2. Gruenwald J, Brendler T, Jaenicke C. PDR for Herbal Medicines. 1st ed. Montvale, NJ: Medical Economics Company, Inc., 1998.
  3. Fetrow CW, Avila JR. Professional's Handbook of Complementary & Alternative Medicines. 1st ed. Springhouse, PA: Springhouse Corp., 1999.

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 Cereus and Flecainide Together: Common Questions

Is it safe to take Cereus with Flecainide?
We do not list a known interaction between Cereus and Flecainide. 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 Cereus and Flecainide 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 Cereus and Flecainide combination checked?
Interactions in our licensed database are recorded against drug classes. Flecainide is filed under 4 classifications, and Cereus has documented interactions with 2 drug classes — none of Flecainide'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 Cereus interact with any other medications?
Yes. Cereus has 10 documented drug interactions in our database — Flecainide 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 Flecainide interact with any supplements?
Yes. Flecainide has documented interactions with 86 supplements in our database — Cereus is not one of them. The Flecainide 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

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

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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.