Drug & supplement interaction

Limosilactobacillus Reuteri + Phentermine

Phentermine brand names: Adipex-P, Fastin, T Diet, Phentride, Obenix, and others.

No Known Interaction

Medically reviewed by Dr. Brian Staiger, PharmD, BCPS · Updated July 2026 · Pair last verified Sep 13, 2026

The bottom line No known interaction

We found no known interaction between Limosilactobacillus Reuteri and Phentermine in our sources. Absence of a documented interaction is not the same as proven safety, and does not guarantee one does not exist. Do not start, stop, or change a medication or supplement based on this page; confirm with your pharmacist or doctor first. Additionally, although there is no interaction, the two are separately associated with some of the same side effects, which would make a new symptom harder to attribute to one or the other.

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Interaction report

Limosilactobacillus Reuteri and Phentermine

We checked these two against our interaction database. Here is what we found.

No Known Interaction Found

We did not find a documented interaction between Phentermine and Limosilactobacillus Reuteri in our sources. This does not guarantee that the combination is completely free of risk — there is often limited research on supplements and herbal products, especially around drug interactions.

If you decide to take both, the practical routine is simple: add one new thing at a time and note the date you started it. If the combination is going to disagree with you, it usually shows in the first days to a couple of weeks — and a start date turns “I’ve been feeling off” into something a pharmacist can actually work with. Do not stop a prescribed medicine on your own.

Always talk with your pharmacist or doctor before making changes to your medications or supplements, particularly if you take several medications or have an ongoing health condition.

Limosilactobacillus Reuteri safety at a glance

Limosilactobacillu... overall Use caution Generally well tolerated in healthy people, but caution is needed in those who are seriously ill or immunocompromised.

Pregnancy Possibly Safe When used orally and appropriately. Read the full pregnancy detail

Breastfeeding Possibly Safe When used orally and appropriately. Although clinical research during lactation is lacking, no safety concerns have been shown in clinical research involving in... Read the full breastfeeding detail

Pregnancy & breastfeeding ratings are from Natural Medicines (Therapeutic Research Center) — the full detail is in the Special populations card below. Safety guidance is general; always confirm with your pharmacist or doctor for your situation.

Still wondering about combining Phentermine and Limosilactobacillus Reuteri? Ask Dr. Brian Staiger, PharmD, BCPS directly ›

How we checked

Why No Interaction Is Listed for Phentermine

Interactions in our licensed database are recorded against drug classes, not just single drug names. Phentermine is filed under 2 classifications — stimulant drugs, oral drugs. Limosilactobacillus Reuteri has documented interactions with 1 drug class — the most serious being antibiotic drugs (moderate) — and none of Phentermine’s classifications are among them.

Classification data comes from our licensed Natural Medicines dataset. A medication can belong to classes beyond those recorded there, so this describes how the check was run — it is not a safety guarantee.

Keep it in perspective

Limosilactobacillus Reuteri Does Interact With Other Medications

Limosilactobacillus Reuteri has 182 moderate known drug interactions in our database — Phentermine isn’t one of them. If you take anything else, check it against the full list below.

Moderate 182 No known interaction 2,648 (incl. Phentermine)

Taking anything else?

Check Another of Your Medications Against Limosilactobacillus Reuteri

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

What to actually watch for

No Interaction Found — But Data Suggests Limosilactobacillus Reuteri and Phentermine May Share Several of the Same Side Effects

This is not an interaction. Neither one changes how your body handles the other, and nothing here says they react together. What our sources do show is that each has separately been linked to the effects below — so taking both can make those effects more likely to turn up, and harder to pin on one or the other if they do.

Constipation / Diarrhea Additional detail
Limosilactobacillus Reuteri
“Orally, taking Limosilactobacillus reuteri alone or in combination with other probiotics may cause gastrointestinal side effects including diarrhea and constipation; however, these events are uncommon.”

Limosilactobacillus Reuteri · Natural Medicines adverse-effect record, reported in constipation.
2 sources cited

90235. Beerepoot MA, ter Riet G, Nys S, van der Wal WM, de Borgie CA, de Reijke TM,Prins JM, Koeijers J, Verbon A, Stobberingh E, Geerlings SE. Lactobacilli vs antibiotics to prevent urinary tract infections: a randomized, double-blind, noninferiority trial in p DOI

107507. Ojetti V, Gigante G, Gabrielli M, et al. The effect of oral supplementation with Lactobacillus reuteri or tilactase in lactose intolerant patients: randomized trial. Eur Rev Med Pharmacol Sci. 2010;14(3):163-70.
Phentermine

Listed in the ADVERSE REACTIONS section of the FDA label for Phentermine. Read the label on DailyMed ›

Reported for Limosilactobacillus Reuteri but not commonly for Phentermine: a higher chance of infection.

Effects for Phentermine come from the ADVERSE REACTIONS section of its FDA label; effects for Limosilactobacillus Reuteri come from the Natural Medicines adverse-effect record, quoted above. Wording is matched across sources by our own clinical vocabulary, so treat this as a prompt to pay attention, not a diagnosis.

Special populations

Limosilactobacillus Reuteri in Pregnancy & Breastfeeding

Pregnancy Possibly Safe

When used orally and appropriately.

Lactation Possibly Safe

When used orally and appropriately. Although clinical research during lactation is lacking, no safety concerns have been shown in clinical research involving infants up to 3 months of age.

DISCLAIMER: This tool is intended for informational purposes only, and should not be interpreted as specific medical advice. Patients should consult with a qualified healthcare provider before making decisions about therapies and/or health conditions.© 2026 Therapeutic Research Center

Overlapping uses

What Phentermine Is Prescribed For, and What Limosilactobacillus Reuteri Has Been Studied For

These two come up together because they touch the same health topic — not because they do the same job. Phentermine is a prescription medicine with approved uses on its FDA label. Limosilactobacillus Reuteri is a supplement: what follows is what researchers have looked at it for, and how strong that evidence is.

Phentermine is prescribed for: Phentermine is approved as a short-term addition to a weight-loss program — not a standalone treatment. It is used alongside reduced-calorie eating, increased physical activity, and behavior changes to help manage obesity in adults whose body mass index (BMI) is 30 kg/m² or higher, or 27 kg/m² or higher when other risk factors such as controlled high blood pressure, diabetes, or high cholesterol (hyperlipidemia) are also present. All available phentermine products — including Adipex-P, Lomaira, and various generic capsules and tablets — share this same FDA-approved use. Lomaira tablets are specifically dosed to be taken three times daily before meals, while other formulations are generally taken once daily.

Read the rest of what Phentermine is prescribed for

Treatment is intended to last only a few weeks.

Limosilactobacillus Reuteri has been studied for:

Obesity studied, not established Limosilactobacillus Reuteri has been studied for this. Natural Medicines rates the evidence: Insufficient Reliable Evidence To Rate Read what the research shows

Limosilactobacillus Reuteri for obesity

Although there has been interest in using oral Limosilactobacillus reuteri for obesity, there is insufficient reliable information about the clinical effects of L. reuteri for this condition.

Effectiveness ratings and the research summaries above are the verbatim record from the Natural Medicines database, which grades evidence from “Effective” down to “Insufficient Reliable Evidence To Rate”. A rating below the top of that scale means researchers have looked at it — not that it works, and never that it can stand in for a prescribed medicine. Do not stop or replace Phentermine on your own; if you are taking Limosilactobacillus Reuteri for the same health topic, tell your prescriber, especially if the medicine is being adjusted to a target.

From our Q&A

Questions About Limosilactobacillus Reuteri or Phentermine

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

This page covers Limosilactobacillus Reuteri only. If you take other supplements — a multivitamin, a sleep aid, something for joints — the Phentermine page lists 61 supplements it has a documented interaction with, worst first, each one explained.

The most serious there right now: Activated Charcoal (major), Ephedra (major), Peyote (major), Rauvolfia Vomitoria (major) and Sida Cordifolia (major).

By severity: 5 major · 43 moderate · 13 minor.

From our pharmacist’s overview on the Phentermine page

“Ephedra is the pairing I most want anyone taking phentermine (Adipex-P) to know about. Phentermine is itself a stimulant appetite suppressant that raises heart rate and blood pressure, and ephedra piles the same cardiovascular strain on top of it.”

Reviewed by 2 · Jul 18, 2026

Open the Phentermine interaction page

How much people look this up

Where Limosilactobacillus Reuteri and Phentermine 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 Reuteri

Steady interest

#1,147 of 1,452 supplements looked up here in the last 7 days

29 days ago today

Medication Phentermine

Top 10%

#280 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.

Where does our data come from?

Source: the Natural Medicines (TRC Healthcare) clinical database — the evidence-graded professional reference for herb & supplement interactions.
Citation library: 103,510 references behind our interaction content, 65,311 of them resolved to verified PubMed/DOI sources. See every Limosilactobacillus Reuteri reference on this page ↓
Freshness: we automatically re-check this combination every week — this pair was last verified September 13, 2026. The Limosilactobacillus Reuteri and Phentermine records this page draws on were last updated July 11, 2026.
What “no known interaction” means: no documented interaction in the sources above — not a guarantee of safety. Supplements are studied far less than prescription drugs, so we say exactly what the evidence supports, and nothing more.

Data structure & sourcing designed and verified by Dr. Brian Staiger, PharmD, BCPS.

Supplement

About Limosilactobacillus Reuteri

What is Limosilactobacillus Reuteri?

Infant colic
Diarrhea (including antibiotic-associated)
Digestive health
Oral and gum health
Constipation
Immune support

Limosilactobacillus reuteri (formerly Lactobacillus reuteri) is a probiotic bacterium found in the human gut and certain fermented foods. It has the most supportive evidence for reducing crying in breastfed infants with colic and for some types of diarrhea, while many other uses remain unproven. It is generally well tolerated in healthy people, but people who are very ill or immunocompromised should talk to a doctor first.

Limosilactobacillus reuteri · Lactobacillaceae · Live bacterial cells (probiotic strains) · Chewable tablets, drops/oils, capsules, powders, fortified foods and yogurt

An interaction check asks whether these two react with each other — it does not ask whether Limosilactobacillus Reuteri is a good idea for someone in your situation. Here is what our Limosilactobacillus Reuteri record says about it on its own.

Limosilactobacillus Reuteri: dosing

There is no single official dose for L. reuteri. Do not assume a higher dose is better.

From our Limosilactobacillus Reuteri monograph — the full record covers uses, side effects and every documented interaction.

Read the full Limosilactobacillus Reuteri monograph & all interactions

Medication

About Phentermine

What Is Phentermine Used For?

Brand names: Adipex-P, Fastin, T Diet, Phentride, Obenix, Pbc Phentride, Pbw Phentride, Phentrol #3, Ionamin, Phentrol #6, Phentrol #2, Phentrol #5, Phentrol, Obermine, Phentermine, Suprenza

Phentermine is approved as a short-term addition to a weight-loss program — not a standalone treatment. It is used alongside reduced-calorie eating, increased physical activity, and behavior changes to help manage obesity in adults whose body mass index (BMI) is 30 kg/m² or higher, or 27 kg/m² or higher when other risk factors such as controlled high blood pressure, diabetes, or high cholesterol (hyperlipidemia) are also present.

All available phentermine products — including Adipex-P, Lomaira, and various generic capsules and tablets — share this same FDA-approved use. Lomaira tablets are specifically dosed to be taken three times daily before meals, while other formulations are generally taken once daily. Treatment is intended to last only a few weeks.

See full Phentermine drug information

Keep checking

Other Drugs & Limosilactobacillus Reuteri

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

0Major

182Moderate

0Minor

2,647No known interaction

182 Moderate 2,647 No interaction

Moderate

182 interactions

Showing 60 of 182 moderate interactions — see all 182 on the Limosilactobacillus Reuteri page.

No interaction 2,647 drugs checked — show the list

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

Showing the 60 most looked-up of 2,647 medications checked with no known interaction — see the full Limosilactobacillus Reuteri list.

See the full Limosilactobacillus Reuteri interactions page

See every supplement checked against Phentermine, ranked by severity

Evidence & sources

Limosilactobacillus Reuteri References

The 14 references that drive our Limosilactobacillus Reuteri monograph and interaction data, from the evidence-graded Natural Medicines (TRC Healthcare) database. Citations with a link open the study on PubMed or the publisher’s site.

Pierce A. The American Pharmaceutical Association Practical Guide to Natural Medicines. New York: The Stonesong Press, 1999:19.
Savino F, Cordisco L, Tarasco V, et al. Lactobacillus reuteri DSM 17938 in infantile colic: a randomized, double-blind, placebo-controlled trial. Pediatrics 2010;126:e526-33.
Savino F, Pelle E, Palumeri E, et al. Lactobacillus reuteri (American Type Culture Collection Strain 55730) versus simethicone in the treatment of infantile colic: a prospective randomized study. Pediatrics 2007;119:e124-30.
Beerepoot MA, ter Riet G, Nys S, van der Wal WM, de Borgie CA, de Reijke TM,Prins JM, Koeijers J, Verbon A, Stobberingh E, Geerlings SE. Lactobacilli vs antibiotics to prevent urinary tract infections: a randomized, double-blind, noninferiority trial in p DOI
Chau K, Lau E, Greenberg S, Jacobson S, Yazdani-Brojeni P, Verma N, Koren G.Probiotics for infantile colic: a randomized, double-blind, placebo-controlled trial investigating Lactobacillus reuteri DSM 17938. J Pediatr 2015;166(1):74-8. PubMed
Indrio F, Di Mauro A, Riezzo G, Civardi E, Intini C, Corvaglia L, Ballardini E, Bisceglia M, Cinquetti M, Brazzoduro E, Del Vecchio A, Tafuri S, Francavilla R. Prophylactic use of a probiotic in the prevention of colic, regurgitation, and functional const
Oncel MY, Sari FN, Arayici S, Guzoglu N, Erdeve O, Uras N, Oguz SS, Dilmen U. Lactobacillus Reuteri for the prevention of necrotising enterocolitis in very low birthweight infants: a randomised controlled trial. Arch Dis Child Fetal Neonatal Ed. 2014;99(2
Sung V, Hiscock H, Tang ML, Mensah FK, Nation ML, Satzke C, Heine RG, Stock A,Barr RG, Wake M. Treating infant colic with the probiotic Lactobacillus reuteri: double blind, placebo controlled randomised trial. BMJ. 2014 1;348:g2107. PubMed
Szajewska H, Gyrczuk E, Horvath A. Lactobacillus reuteri DSM 17938 for the management of infantile colic in breastfed infants: a randomized, double-blind,placebo-controlled trial. J Pediatr. 2013;162(2):257-62. PubMed
Husain S, Allotey J, Drymoussi Z, et al. Effects of oral probiotic supplements on vaginal microbiota during pregnancy: a randomised, double-blind, placebo-controlled trial with microbiome analysis. BJOG. 2020;127(2):275-284. PubMed
Ojetti V, Gigante G, Gabrielli M, et al. The effect of oral supplementation with Lactobacillus reuteri or tilactase in lactose intolerant patients: randomized trial. Eur Rev Med Pharmacol Sci. 2010;14(3):163-70.
Rossi F, Amadoro C, Gasperi M, Colavita G. Lactobacilli infection case reports in the last three years and safety implications. Nutrients. 2022;14(6):1178. PubMed
Sheyholislami H, Connor KL. Are probiotics and prebiotics safe for use during pregnancy and lactation? A systematic review and meta-analysis. Nutrients. 2021;13(7):2382. PubMed
Yefet E, Colodner R, Strauss M, Gam Ze Letova Y, Nachum Z. A randomized controlled open label crossover trial to study vaginal colonization of orally administered Lactobacillus reuteri RC-14 and rhamnosus GR-1 in pregnant women at high risk for preterm la

Medication overviews come from MedlinePlus (NIH); supplement label data from the NIH Dietary Supplement Label Database. Content is written and reviewed by licensed HelloPharmacist pharmacists — see our data sources and editorial standards.

Pharmacist Counseling Corner

Taking Limosilactobacillus Reuteri and Phentermine Together: Common Questions

Is it safe to take Limosilactobacillus Reuteri with Phentermine?

We do not list a known interaction between Limosilactobacillus Reuteri and Phentermine. That does not guarantee the combination is risk-free, so confirm with your pharmacist or doctor — especially if you take other medications or have a health condition.

Do Limosilactobacillus Reuteri and Phentermine have any of the same side effects?

Yes — our sources link each of them separately to 2 of the same effects. That is not an interaction: neither changes how your body handles the other. It does mean that if one of those effects turns up, it can be harder to tell which one is behind it. They are listed on this page with the source behind each.

Are Limosilactobacillus Reuteri and Phentermine used for the same thing?

They overlap in purpose, which usually means the real question is whether you need both rather than whether they are safe together. This page lists the shared uses and how strong the evidence is for Limosilactobacillus Reuteri in each. That is a conversation for your prescriber, especially if Phentermine is being adjusted to a target.

How was the Limosilactobacillus Reuteri and Phentermine combination checked?

Interactions in our licensed database are recorded against drug classes. Phentermine is filed under 2 classifications, and Limosilactobacillus Reuteri has documented interactions with 1 drug class — none of Phentermine's classifications are among them. A medication can belong to classes beyond those recorded in our dataset, so this describes how the check was run rather than guaranteeing safety.

Does Limosilactobacillus Reuteri interact with any other medications?

Yes. Limosilactobacillus Reuteri has 182 documented drug interactions in our database — Phentermine is simply not one of them. If you take anything else, it is worth checking each one; they are all listed on this page.

Does Phentermine interact with any supplements?

Yes. Phentermine has documented interactions with 61 supplements in our database — Limosilactobacillus Reuteri is not one of them. The Phentermine interaction page linked on this page lists every one, ranked by severity.

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

Where next

Keep Exploring

Limosilactobacillus Reuteri monograph Uses, safety profile, and every drug interaction in one place Phentermine drug information The full plain-English guide to this medication Phentermine supplement interactions Every supplement checked against Phentermine, ranked by severity Supplement interaction checker Check any supplement or product against your medications Browse medications A–Z Every drug we’ve checked against herbs & supplements References The 14 citations behind this page Ask a pharmacist Free, personal answer from our licensed team

Still Have a Question About Phentermine and Limosilactobacillus Reuteri?

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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.