Drug & supplement interaction

Lacticaseibacillus Casei + Aztreonam

Aztreonam brand name: Azactam.

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

Lacticaseibacillus Casei has a moderate interaction with Aztreonam. Theoretically, taking Lacticaseibacillus casei 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

Lacticaseibacillus Casei and Aztreonam

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

Moderate

ANTIBIOTIC DRUGS

Why this applies to Aztreonam

Aztreonam falls under ANTIBIOTIC DRUGS — the group Lacticaseibacillus Casei interacts with.

Theoretically, taking Lacticaseibacillus casei with antibiotic drugs might decrease the effectiveness of L. casei.
L. casei 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. casei 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: aztreonam is an antibiotic, and antibiotics don't tell the difference between bad bacteria and the friendly bacteria in your probiotic. Since L. casei is a live organism, taking your dose of this probiotic right alongside aztreonam may kill off a good chunk of those helpful bugs before they get a chance to do anything. In other words, this interaction works against the probiotic, not against your antibiotic.

Good news is your aztreonam keeps working just fine, so your infection treatment isn't weakened. To get the most out of the L. casei, a simple fix is to space the two apart by at least a couple of hours. This is based on how the drug works rather than hard studies, so it's a low-risk situation. Your pharmacist can help you map out the timing.

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

Lacticaseibacillus Casei Also Interacts With Other Medications

Lacticaseibacillus Casei has 181 moderate known drug interactions in our database — the Aztreonam 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. Aztreonam)
Taking anything else?

Check Another of Your Medications Against Lacticaseibacillus Casei

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

Everything else you take

See Every Supplement That Interacts With Aztreonam

This page covers Lacticaseibacillus Casei only. If you take other supplements — a multivitamin, a sleep aid, something for joints — the Aztreonam page lists 27 supplements it has a documented interaction with, worst first, each one explained.

The most serious there right now: Bacillus Coagulans (moderate), Bacillus Subtilis (moderate), Bifidobacterium Animalis Subsp. Lactis (moderate), Bifidobacterium Bifidum (moderate) and Bifidobacterium Breve (moderate).

By severity: 26 moderate · 1 minor.

From our pharmacist’s overview on the Aztreonam page

“Every entry on this page tells one story, and it is a gentler one than most interaction lists. Aztreonam (Azactam) is an injectable or inhaled antibiotic used for serious infections, often in people with cystic fibrosis, and none of these 27 supplement pairings makes the drug itself riskier or weaker.”

Reviewed by 2 · Jul 18, 2026

Open the Aztreonam interaction page

How much people look this up

Where Lacticaseibacillus Casei and Aztreonam 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 Lacticaseibacillus Casei
Top half

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

29 days ago today
Medication Aztreonam
Steady interest

#2,168 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 Lacticaseibacillus Casei

What is Lacticaseibacillus Casei?

  • Digestive health
  • Diarrhea (including antibiotic-related)
  • Immune support
  • Constipation
  • Gut microbiome balance

Lacticaseibacillus casei (formerly Lactobacillus casei) is a 'friendly' probiotic bacterium found in fermented foods and many supplements. It is most studied for digestive issues like diarrhea, where some evidence is encouraging, but results vary by strain and condition. It is generally well tolerated in healthy people, but those with weakened immune systems should check with a doctor first.

Read the full Lacticaseibacillus Casei monograph & all interactions
Medication

About Aztreonam Injection

What Is Aztreonam Injection Used For?

Brand name: Azactam

Azactam (aztreonam for injection) is used to treat infections caused by susceptible gram-negative bacteria. It is approved for urinary tract infections (including kidney infections and bladder infections), lower respiratory tract infections (including pneumonia), bloodstream infections (septicemia), skin and skin-structure infections (including those related to wounds, ulcers, and burns), intra-abdominal infections (including peritonitis), and gynecologic infections (including endometritis and pelvic cellulitis).

Azactam is also used alongside surgery to manage infections such as abscesses and infections involving perforated organs. In seriously ill patients who may also have gram-positive bacterial infections, it is often started together with another antibiotic that covers those bacteria. When anaerobic bacteria (bacteria that don't need oxygen) are also suspected, an anti-anaerobic antibiotic is added as well.

See full Aztreonam Injection drug information
Keep checking

Other Drugs & Lacticaseibacillus Casei

Browse every other medication we’ve checked against Lacticaseibacillus Casei — 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 Lacticaseibacillus Casei page.

No interaction 2,648 drugs checked — show the list

We also checked Lacticaseibacillus Casei 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 Lacticaseibacillus Casei list.

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

Can you take Lacticaseibacillus Casei with Aztreonam?
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 Lacticaseibacillus Casei and Aztreonam 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 Aztreonam and Lacticaseibacillus Casei?

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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.