Drug & supplement interaction

Sida Cordifolia + Flecainide

Flecainide brand name: Tambocor.

Major Interaction
Medically reviewed by · Updated September 2026
The bottom line Major

Sida Cordifolia has a major interaction with Flecainide. Theoretically, Sida cordifolia might increase the risk of additive QT interval prolongation when taken with QT interval-prolonging drugs.

Read the full interaction report
SeverityMajor
LikelihoodProbable
EvidenceB
What do Severity, Likelihood & Evidence mean?
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Interaction report

Sida Cordifolia and Flecainide

Here is the interaction we found between these two, with the evidence behind it.

Major

QT INTERVAL-PROLONGING DRUGS

Why this applies to Flecainide

Flecainide falls under QT INTERVAL-PROLONGING DRUGS — the group Sida Cordifolia interacts with.

Theoretically, Sida cordifolia might increase the risk of additive QT interval prolongation when taken with QT interval-prolonging drugs.
Sida cordifolia contains ephedrine. Clinical research shows that ephedrine from another herb, ephedra, can prolong the QT interval.
Severity Major Likelihood Probable Evidence B

Interaction has not been documented in well-controlled studies, however, the interaction has been demonstrated in some small human studies or in controlled animal studies in conjunction with multiple case reports..

Dr. Brian Staiger, PharmD, BCPS
Dr. Brian Staiger explains PharmD, Clinical Pharmacist

Here's the concern with pairing Sida cordifolia and flecainide. Flecainide already works by slowing electrical signals in your heart, and it can stretch out part of your heart's rhythm cycle (the QT interval). Sida cordifolia naturally contains ephedrine, a stimulant that can also nudge that same interval longer. Stack them together and the effect may add up.

Why that matters: a longer QT can, in rare cases, trigger a dangerous heart rhythm, with symptoms like a racing or fluttering heartbeat, dizziness, or fainting. Ephedrine's stimulant push on your heart rate and blood pressure isn't ideal when you're on a heart rhythm drug either. This is mostly theoretical and based on limited evidence, but flecainide is a heart medicine where I wouldn't take chances. Please check with your pharmacist or doctor before using this supplement.

Contact Dr. Brian directly if you have additional questions on this interaction
References
  1. McBride BF, Karapanos AK, Krudysz A, et al. Electrocardiographic and hemodynamic effects of a multicomponent dietary supplement containing ephedra and caffeine: a randomized controlled trial. JAMA 2004;291:216-21. PubMed

What These Ratings Mean

Every interaction above is graded three ways — here’s the key to each label.

Severity how clinically significant the interaction is
Major

Clinically significant. Avoid the combination, or use only under close professional supervision.

Moderate

Usually worth avoiding or managing — may need monitoring, a dose change, or timing apart.

Minor

Generally not serious. Be aware of it and mention it to your pharmacist.

Likelihood how strong the evidence is that the interaction actually happens in people
  • LikelyWell-controlled human studies have demonstrated the likely existence of this interaction.
  • ProbableInteraction has not been documented in well-controlled studies, however, the interaction has been demonstrated in some small human studies or in controlled animal studies in conjunction with multiple case reports.
  • PossibleInteraction has been documented in animal or in lab research, or the interaction has been documented in humans but is limited to case reports or conflicting clinical research exists.
  • UnlikelyInteraction has been demonstrated in animal or in lab research but has been shown not to occur in humans.
Evidence the quality of the studies behind the rating (graded A–D)
  • AHigh-quality meta-analysis (quantitative systematic review).
  • BCase-control study.
  • CConsensus.
  • DAnecdotal evidence.

These ratings are for information only. Never start, stop, or otherwise change your therapy before speaking with your provider.

Keep it in perspective

Sida Cordifolia Also Interacts With Other Medications

Sida Cordifolia has 336 major, 108 moderate known drug interactions in our database — the Flecainide one above is one of them. If you take anything else, check it against the full list below.

Major 336 Moderate 108 No known interaction 2,386 (incl. Flecainide)
Taking anything else?

Check Another of Your Medications Against Sida Cordifolia

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

From our Q&A

Questions About Sida Cordifolia 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 Sida Cordifolia 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 Sida Cordifolia 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 Sida Cordifolia as Part of a Dietary Supplement Product? Check It for Interactions

We hold 48 real supplement products containing Sida Cordifolia, each one broken down to its full ingredient list — and combination products often carry several ingredients besides Sida Cordifolia. Your product may carry other ingredients that interact with Flecainide too, on top of Sida Cordifolia — and those would not show on this page. Find your product and we’ll check every ingredient on its label:

How much people look this up

Where Sida Cordifolia 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 Sida Cordifolia
Top half

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

29 days ago today
Medication Flecainide
Top 25%

#527 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.

Supplement

About Sida Cordifolia

What is Sida Cordifolia?

Sida Cordifolia
  • Weight loss and energy
  • Asthma and breathing problems
  • Joint and muscle pain
  • Fever and cough
  • General fatigue or 'tonic'

Sida cordifolia (bala or country mallow) is a traditional Ayurvedic plant that naturally contains ephedrine, a powerful stimulant. Because of this, many supplements containing it have been banned or restricted, and it carries real risks to the heart and blood pressure. There is little reliable human evidence that it works, so most people should avoid it and talk with a pharmacist or doctor first.

Read the full Sida Cordifolia 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 & Sida Cordifolia

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

336Major
108Moderate
0Minor
2,385No known interaction
336 Major 108 Moderate 2,385 No interaction
Major

336 interactions

Showing 60 of 336 major interactions — see all 336 on the Sida Cordifolia page.

Moderate

108 interactions

Showing 60 of 108 moderate interactions — see all 108 on the Sida Cordifolia page.

No interaction 2,385 drugs checked — show the list

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

Showing the 60 most looked-up of 2,385 medications checked with no known interaction — see the full Sida Cordifolia list.

See the full Sida Cordifolia interactions page
See every supplement checked against Flecainide, ranked by severity
Sources

Sources & How We Checked

Interaction details are evidence-graded and sourced from the Natural Medicines database. The medication overview comes from MedlinePlus.

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
Sida Cordifolia monograph › Uses, safety, and every drug interaction in one place Flecainide supplement interactions › Every supplement checked against Flecainide, ranked by severity Flecainide 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 Sida Cordifolia and Flecainide Together: Common Questions

Can you take Sida Cordifolia with Flecainide?
This is rated a major interaction, so the combination is best avoided unless your doctor or pharmacist has specifically told you otherwise. Read the full details on this page and confirm with your pharmacist before combining them.
How serious is the Sida Cordifolia and Flecainide interaction?
We rate it Major. This is a clinically significant combination that is generally best avoided, or used only under the direct supervision of your physician or pharmacist.

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

Still Have a Question About Flecainide and Sida Cordifolia?

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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.