Drug & supplement interaction

Bifidobacterium Bifidum + Trimethoprim

Trimethoprim brand names: Proloprim, Trimpex.

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

Bifidobacterium Bifidum has a moderate interaction with Trimethoprim. Theoretically, taking Bifidobacterium. bifidum with antibiotic drugs might decrease the effectiveness of B.

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

Bifidobacterium Bifidum and Trimethoprim

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

Moderate

ANTIBIOTIC DRUGS

Why this applies to Trimethoprim

Trimethoprim falls under ANTIBIOTIC DRUGS — the group Bifidobacterium Bifidum interacts with.

Theoretically, taking Bifidobacterium. bifidum with antibiotic drugs might decrease the effectiveness of B. bifidum.
Since B. bifidum preparations usually contain live and active organisms, simultaneously taking antibiotics might kill a significant number of the organisms. Tell patients to separate administration of antibiotics and B. bifidum preparations by at least 2 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 with this pairing: it's not that your probiotic harms the antibiotic, it's the other way around. Trimethoprim is an antibiotic, so it kills bacteria, and the friendly bacteria in your Bifidobacterium bifidum supplement are no exception. If you swallow them at the same time, the antibiotic may wipe out a good chunk of those live organisms before they can do their job, so you simply get less benefit from the probiotic.

This won't change how well your trimethoprim clears your infection, and it's a theoretical concern based on how these products work rather than hard clinical proof. An easy fix is to space them out by at least 2 hours. As always, check with your pharmacist or doctor if you have questions.

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.
  2. Xiao JZ, Takahashi S, Odamaki T, et al. Antibiotic susceptibility of bifidobacterial strains distributed in the Japanese market. Biosci Biotechnol Biochem. 2010;74(2):336-42. 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

Bifidobacterium Bifidum Also Interacts With Other Medications

Bifidobacterium Bifidum has 181 moderate known drug interactions in our database — the Trimethoprim 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. Trimethoprim)
Taking anything else?

Check Another of Your Medications Against Bifidobacterium Bifidum

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

From our Q&A

Questions About Bifidobacterium Bifidum or Trimethoprim

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

This page covers Bifidobacterium Bifidum only. If you take other supplements — a multivitamin, a sleep aid, something for joints — the Trimethoprim page lists 59 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 · 41 moderate · 11 minor.

From our pharmacist’s overview on the Trimethoprim page

“Most prescriptions for trimethoprim are short courses for bladder infections, which makes it easy to assume nothing swallowed alongside it matters much. Seven of the 59 supplement and herbal ingredients here rate major, though, and nearly all of them involve heart rhythm: grapefruit in large amounts, ephedra, and a few others can prolo…”

Reviewed by 2 · Jul 18, 2026

Open the Trimethoprim interaction page

One more smart check

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

We hold 3,041 real supplement products containing Bifidobacterium Bifidum, each one broken down to its full ingredient list — and combination products often carry several ingredients besides Bifidobacterium Bifidum. Your product may carry other ingredients that interact with Trimethoprim too, on top of Bifidobacterium Bifidum — 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 Bifidobacterium Bifidum and Trimethoprim 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 Bifidobacterium Bifidum
Top 10%

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

29 days ago today
Medication Trimethoprim
Steady interest

#1,454 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 Bifidobacterium Bifidum

What is Bifidobacterium Bifidum?

  • Digestive health and regularity
  • Diarrhea (including antibiotic-related)
  • Irritable bowel syndrome (IBS) symptoms
  • Supporting gut and immune balance
  • Infant gut health

Bifidobacterium bifidum is a 'friendly' bacteria (probiotic) that naturally lives in the human gut and is taken to support digestion and gut balance. Some evidence suggests probiotics may help with certain types of diarrhea and digestive discomfort, but results vary by strain and condition. It is generally well tolerated in healthy people, but anyone who is seriously ill or has a weakened immune system should check with a doctor first.

Read the full Bifidobacterium Bifidum monograph & all interactions
Medication

About Trimethoprim

What Is Trimethoprim Used For?

Brand names: Proloprim, Trimpex

Trimethoprim tablets are used to treat initial episodes of uncomplicated urinary tract infections (UTIs). It works against specific bacteria — including E. coli, Proteus mirabilis, Klebsiella pneumoniae, Enterobacter species, and coagulase-negative Staphylococcus species (including S. saprophyticus).

It should only be used when there is a proven or strongly suspected bacterial infection. Your doctor may order a urine culture to confirm which bacteria are present and whether trimethoprim will work against them.

See full Trimethoprim drug information
Keep checking

Other Drugs & Bifidobacterium Bifidum

Browse every other medication we’ve checked against Bifidobacterium Bifidum — 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 Bifidobacterium Bifidum page.

No interaction 2,648 drugs checked — show the list

We also checked Bifidobacterium Bifidum 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 Bifidobacterium Bifidum list.

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

Can you take Bifidobacterium Bifidum with Trimethoprim?
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 Bifidobacterium Bifidum and Trimethoprim 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 Trimethoprim and Bifidobacterium Bifidum?

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.