Drug & supplement interaction

Limosilactobacillus Fermentum + Rifapentine

Rifapentine brand name: Priftin.

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

Limosilactobacillus Fermentum has a moderate interaction with Rifapentine. Theoretically, taking Limosilactobacillus fermentum with antibiotic drugs might decrease the effectiveness of L.

Read the full interaction report
SeverityModerate
LikelihoodProbable
EvidenceD
What do Severity, Likelihood & Evidence mean?
Know someone taking this? Share
Facebook Post Reddit Email
On this page
Interaction report

Limosilactobacillus Fermentum and Rifapentine

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

Moderate

ANTIBIOTIC DRUGS

Why this applies to Rifapentine

Rifapentine falls under ANTIBIOTIC DRUGS — the group Limosilactobacillus Fermentum interacts with.

Theoretically, taking Limosilactobacillus fermentum with antibiotic drugs might decrease the effectiveness of L. fermentum.
Limosilactobacillus fermentum 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. fermentum 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 simple version: this interaction runs in one direction. Rifapentine is an antibiotic, and L. fermentum is a live probiotic. If you swallow them at the same time, the rifapentine can kill off a good chunk of those friendly bacteria before they ever get a chance to do their job. So it's the probiotic that loses out here, not your TB treatment.

The good news is your rifapentine keeps working just fine, so you're still getting the full benefit against the tuberculosis. To get more value out of the probiotic, a common tip is to space them apart by at least two hours. This is based on how these products work rather than hard clinical studies, so it's more of a sensible precaution. Your pharmacist can help you set up a simple timing schedule.

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

Limosilactobacillus Fermentum Also Interacts With Other Medications

Limosilactobacillus Fermentum has 181 moderate known drug interactions in our database — the Rifapentine 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. Rifapentine)
Taking anything else?

Check Another of Your Medications Against Limosilactobacillus Fermentum

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

Everything else you take

See Every Supplement That Interacts With Rifapentine

This page covers Limosilactobacillus Fermentum only. If you take other supplements — a multivitamin, a sleep aid, something for joints — the Rifapentine page lists 64 supplements it has a documented interaction with, worst first, each one explained.

The most serious there right now: Activated Charcoal (major), Alkanna (moderate), Alpine Ragwort (moderate), Bacillus Coagulans (moderate) and Bacillus Subtilis (moderate).

By severity: 1 major · 53 moderate · 10 minor.

From our pharmacist’s overview on the Rifapentine page

“Rifapentine (Priftin) treats tuberculosis and is often dosed just once or twice a week, so a single blunted dose costs more than it would with a daily pill. That is why I read this list of 64 interacting supplements as a real warning rather than routine fine print.”

Reviewed by 2 · Jul 18, 2026

Open the Rifapentine interaction page

How much people look this up

Where Limosilactobacillus Fermentum and Rifapentine 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 Limosilactobacillus Fermentum
Steady interest

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

29 days ago today
Medication Rifapentine
Top half

#1,221 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 Limosilactobacillus Fermentum

What is Limosilactobacillus Fermentum?

  • Digestive health
  • Immune support
  • Vaginal and urinary health
  • Cholesterol support
  • Oral health

Limosilactobacillus fermentum (formerly Lactobacillus fermentum) is a probiotic bacterium found in fermented foods and the human body, used to support gut, immune, and women's health. Early research is promising for some uses but most evidence is preliminary, and effects can differ by strain. It is generally well tolerated in healthy people, but talk to your pharmacist or doctor before starting, especially if your immune system is weak.

Read the full Limosilactobacillus Fermentum monograph & all interactions
Medication

About Rifapentine

What Is Rifapentine Used For?

Brand name: Priftin

Rifapentine (brand name Priftin) is used to treat two forms of tuberculosis (TB) caused by Mycobacterium tuberculosis. For active pulmonary TB — an active infection in the lungs — it is approved for patients 12 years and older, always used alongside other TB medicines, never alone. For latent TB infection (LTBI) — where the bacteria are in the body but not causing active illness — it is approved for patients 2 years and older who are at high risk of the infection becoming active, always combined with isoniazid.

Priftin is not appropriate for every TB situation. It should not be used alone at any stage of active TB treatment, and it is not recommended as a once-weekly continuation regimen combined with isoniazid in people living with HIV who have active pulmonary TB, due to a higher risk of treatment failure or relapse.

See full Rifapentine drug information
Keep checking

Other Drugs & Limosilactobacillus Fermentum

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

No interaction 2,648 drugs checked — show the list

We also checked Limosilactobacillus Fermentum 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 Limosilactobacillus Fermentum list.

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

Can you take Limosilactobacillus Fermentum with Rifapentine?
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 Limosilactobacillus Fermentum and Rifapentine 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

Still Have a Question About Rifapentine and Limosilactobacillus Fermentum?

Our pharmacists answer your medication & supplement questions — free.

Ask a pharmacist

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.