Drug & supplement interaction

Limosilactobacillus Reuteri + Phenylephrine

Phenylephrine brand names: Gilchew, AH Chew D, Gilchew IR, Sudafed PE, Biorphen.

No Known Interaction
Medically reviewed by · Updated July 2026 · Pair last verified Sep 13, 2026
The bottom line No known interaction

We found no known interaction between Limosilactobacillus Reuteri and Phenylephrine 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.

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Interaction report

Limosilactobacillus Reuteri and Phenylephrine

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 Phenylephrine 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 Phenylephrine and Limosilactobacillus Reuteri? Ask Dr. Brian Staiger, PharmD, BCPS directly ›
How we checked

Why No Interaction Is Listed for Phenylephrine

Interactions in our licensed database are recorded against drug classes, not just single drug names. Phenylephrine is filed under 5 classifications — including alpha-adrenergic agonists, stimulant drugs, serotonergic drugs. Limosilactobacillus Reuteri has documented interactions with 1 drug class — the most serious being antibiotic drugs (moderate) — and none of Phenylephrine’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 — Phenylephrine 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. Phenylephrine)
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

What Limosilactobacillus Reuteri Itself Has Been Linked To

This is not an interaction — nothing below involves Phenylephrine. It is the side-effect record for Limosilactobacillus Reuteri on its own, from the licensed Natural Medicines monograph. If something new turns up after you add Limosilactobacillus Reuteri, this list is the first place to look. One entry is worth acting on rather than waiting out — marked below.

  • A higher chance of infection Worth acting on Additional detail

    “Since Limosilactobacillus reuteri preparations contain live and active microorganisms, there is some concern that they might cause pathogenic infection in some patients. Some lactobacilli species have been isolated in some cases of bacteremia, sepsis, splenic abscess, endocarditis, necrotizing fasciitis, pancreatic necrosis, and meningoencephalitis.”

    Limosilactobacillus Reuteri · Natural Medicines adverse-effect record, reported in sepsis.

    1 source cited
    1. 107543. 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
  • Constipation / Diarrhea Additional detail

    “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
    1. 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
    2. 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.

Everything above comes from the Natural Medicines adverse-effect record for Limosilactobacillus Reuteri — expand a row for the licensed statement it rests on. We read the ADVERSE REACTIONS section of Phenylephrine’s FDA label too, and the two lists don’t meaningfully overlap — which is why no Phenylephrine column appears here.

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

From our Q&A

Questions About Limosilactobacillus Reuteri or Phenylephrine

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 Phenylephrine, 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 Phenylephrine

This page covers Limosilactobacillus Reuteri only. If you take other supplements — a multivitamin, a sleep aid, something for joints — the Phenylephrine page lists 81 supplements it has a documented interaction with, worst first, each one explained.

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

By severity: 6 major · 60 moderate · 15 minor.

From our pharmacist’s overview on the Phenylephrine page

“If you take phenylephrine (Sudafed PE, Biorphen) for congestion, treat this list as one that needs real attention, since six of its 81 entries carry a major rating. Phenylephrine tightens blood vessels to clear your nose, and more than half of the interactions here come from stimulant ingredients, ephedra above all, that can push blood…”

Reviewed by 2 · Jul 18, 2026

Open the Phenylephrine interaction page

How much people look this up

Where Limosilactobacillus Reuteri and Phenylephrine 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

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

29 days ago today
Medication Phenylephrine
Top 25%

#660 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 Phenylephrine 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 .
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 Phenylephrine

What Is Phenylephrine Used For?

Brand names: Gilchew, AH Chew D, Gilchew IR, Sudafed PE, Biorphen

Phenylephrine is used in a number of different forms for different purposes. Intravenous (IV) phenylephrine — including products like Biorphen and Immphentiv — is given in hospital settings to raise blood pressure in adults when it drops dangerously low due to blood vessel widening (vasodilation), such as during anesthesia. Phenylephrine Hydrochloride Injection 10 mg/mL is also approved for use in septic shock (a life-threatening infection that causes a severe drop in blood pressure).

Nasal spray and drop products (such as Neo-Synephrine and Equate Nasal) temporarily relieve nasal congestion from colds, hay fever, or upper respiratory allergies. Ophthalmic (eye drop) solutions dilate the pupil for eye exams. Rectal suppository products (such as Preparation H and ReVIVOL-XR) help relieve itching, burning, and discomfort associated with hemorrhoids.

Most-Reported Side Effects for Phenylephrine

From FAERS, the FDA’s public side-effect reporting system (221,388 reports, all brands). Reports are voluntary and are not proof the drug caused the effect.

Fatigue 20,609 reports
Headache 17,301 reports
Nausea 16,925 reports
Diarrhea 14,221 reports
Dyspnea 13,719 reports
See full Phenylephrine 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 Phenylephrine, 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.

  1. Pierce A. The American Pharmaceutical Association Practical Guide to Natural Medicines. New York: The Stonesong Press, 1999:19.
  2. 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.
  3. 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.
  4. 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
  5. 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
  6. 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
  7. 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
  8. 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
  9. 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
  10. 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
  11. 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.
  12. 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
  13. 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
  14. 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 Phenylephrine Together: Common Questions

Is it safe to take Limosilactobacillus Reuteri with Phenylephrine?
We do not list a known interaction between Limosilactobacillus Reuteri and Phenylephrine. 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.
How was the Limosilactobacillus Reuteri and Phenylephrine combination checked?
Interactions in our licensed database are recorded against drug classes. Phenylephrine is filed under 5 classifications, and Limosilactobacillus Reuteri has documented interactions with 1 drug class — none of Phenylephrine'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 — Phenylephrine 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 Phenylephrine interact with any supplements?
Yes. Phenylephrine has documented interactions with 81 supplements in our database — Limosilactobacillus Reuteri is not one of them. The Phenylephrine 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 Phenylephrine drug information The full plain-English guide to this medication Phenylephrine supplement interactions Every supplement checked against Phenylephrine, 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

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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.