Drug & supplement interaction

Lactobacillus Helveticus + Nitrofurantoin

Nitrofurantoin brand names: Macrodantin, Furadantin, Furatoin, Macrobid.

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

Lactobacillus Helveticus has a moderate interaction with Nitrofurantoin. Theoretically, taking Lactobacillus helveticus with antibiotic drugs might decrease the effectiveness of L.

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

Lactobacillus Helveticus and Nitrofurantoin

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

Moderate

ANTIBIOTIC DRUGS

Why this applies to Nitrofurantoin

Nitrofurantoin falls under ANTIBIOTIC DRUGS — the group Lactobacillus Helveticus interacts with.

Theoretically, taking Lactobacillus helveticus with antibiotic drugs might decrease the effectiveness of L. helveticus.
Lactobacillus helveticus preparations usually contain live and active organisms. Therefore, simultaneously taking antibiotics might kill a significant number of the organisms. Tell patients to separate administration of antibiotics and L. helveticus preparations by at least two hours.
Severity Moderate Likelihood Probable Evidence D

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 thing to keep in mind: this interaction goes in one direction only. Nitrofurantoin is an antibiotic, so it can kill off the live Lactobacillus helveticus bacteria in your probiotic. That means the probiotic may simply not work as well while you're on the antibiotic. Nitrofurantoin itself isn't weakened or strengthened by the probiotic, so your UTI treatment should still do its job.

The easy fix is timing. Try to separate the two by at least two hours so fewer of the good bacteria get wiped out. Honestly, this is theoretical and based on how the two work, not on strong studies, so don't lose sleep over it. If you want to use a probiotic during or after your antibiotic course, just run the timing by your pharmacist.

Contact Dr. Brian directly if you have additional questions on this interaction
References
  1. Pierce A. The American Pharmaceutical Association Practical Guide to Natural Medicines. New York: The Stonesong Press, 1999:19.

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

Lactobacillus Helveticus Also Interacts With Other Medications

Lactobacillus Helveticus has 181 moderate known drug interactions in our database — the Nitrofurantoin one above is one of them. If you take anything else, check it against the full list below.

Moderate 181 No known interaction 2,649 (incl. Nitrofurantoin)
Taking anything else?

Check Another of Your Medications Against Lactobacillus Helveticus

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

From our Q&A

Questions About Lactobacillus Helveticus or Nitrofurantoin

These are real questions from readers, answered by the pharmacists at HelloPharmacist — written by a person, not generated from a database. Each one covers Lactobacillus Helveticus or Nitrofurantoin, 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 Nitrofurantoin

This page covers Lactobacillus Helveticus only. If you take other supplements — a multivitamin, a sleep aid, something for joints — the Nitrofurantoin page lists 82 supplements it has a documented interaction with, worst first, each one explained.

The most serious there right now: Activated Charcoal (major), Beer (major), Siberian Cocklebur (major), Wine (major) and Ashwagandha (moderate).

By severity: 4 major · 68 moderate · 10 minor.

From our pharmacist’s overview on the Nitrofurantoin page

“Nitrofurantoin (Macrobid, Macrodantin) treats urinary tract infections and can strain the liver on its own, which is why this interaction list deserves genuine care rather than a glance. Of the 82 ingredients on file, 38 can add their own liver stress on top of the drug's, and three of the four major-rated entries fall in that group, i…”

Reviewed by 2 · Jul 18, 2026

Open the Nitrofurantoin interaction page

One more smart check

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

We hold 530 real supplement products containing Lactobacillus Helveticus, each one broken down to its full ingredient list — and combination products often carry several ingredients besides Lactobacillus Helveticus. Your product may carry other ingredients that interact with Nitrofurantoin too, on top of Lactobacillus Helveticus — 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 Lactobacillus Helveticus and Nitrofurantoin 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 Lactobacillus Helveticus
Top half

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

29 days ago today
Medication Nitrofurantoin
Top half

#1,284 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 Lactobacillus Helveticus

What is Lactobacillus Helveticus?

  • Mood and stress support
  • Digestive and gut health
  • Sleep support
  • General immune support
  • Blood pressure support

Lactobacillus helveticus is a lactic acid bacterium used as a probiotic, often combined with other strains in mood, gut, and general wellness products. Early research is interesting—especially for stress and mood and for fermented-milk peptides and blood pressure—but evidence is still limited and not conclusive. It is generally well tolerated in healthy people, but talk to your pharmacist or doctor before using it, especially if you have a weakened immune system.

Read the full Lactobacillus Helveticus monograph & all interactions
Medication

About Nitrofurantoin

What Is Nitrofurantoin Used For?

Brand names: Macrodantin, Furadantin, Furatoin, Macrobid

Nitrofurantoin is used to treat urinary tract infections (UTIs) caused by certain susceptible bacteria. The capsule forms (including Macrodantin) are indicated for UTIs due to susceptible strains of Escherichia coli, enterococci, Staphylococcus aureus, and certain strains of Klebsiella and Enterobacter species. Nitrofurantoin oral suspension (Furadantin) is indicated for adults and children 1 month of age and older for the same types of UTIs.

Nitrofurantoin is not used for kidney infections (pyelonephritis) or infections of the tissue around the kidney (perinephric abscesses). Because it works primarily in the urine and does not spread widely through body tissues, it may not fully clear the infection in some patients, and the UTI may return after treatment.

See full Nitrofurantoin drug information
Keep checking

Other Drugs & Lactobacillus Helveticus

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

0Major
181Moderate
0Minor
2,648No known interaction
181 Moderate 2,648 No interaction
Moderate

181 interactions

Showing 60 of 181 moderate interactions — see all 181 on the Lactobacillus Helveticus page.

No interaction 2,648 drugs checked — show the list

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

Showing the 60 most looked-up of 2,648 medications checked with no known interaction — see the full Lactobacillus Helveticus list.

See the full Lactobacillus Helveticus interactions page
See every supplement checked against Nitrofurantoin, 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
Lactobacillus Helveticus monograph › Uses, safety, and every drug interaction in one place Nitrofurantoin supplement interactions › Every supplement checked against Nitrofurantoin, ranked by severity Nitrofurantoin 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 Lactobacillus Helveticus and Nitrofurantoin Together: Common Questions

Can you take Lactobacillus Helveticus with Nitrofurantoin?
There is a moderate interaction, so it may be acceptable with monitoring or timing changes — but check with your pharmacist first. Read the full details on this page and confirm with your pharmacist before combining them.
How serious is the Lactobacillus Helveticus and Nitrofurantoin interaction?
We rate it Moderate. This combination may require monitoring, a dose adjustment, or separating the times you take each one. Consult your pharmacist before using them together.

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

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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.