Drug & supplement interaction

Secretin + 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 Oct 4, 2026
The bottom line No known interaction

We found no known interaction between Secretin 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. 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

Secretin 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 Secretin 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.

Worth understanding: our licensed dataset holds no drug-interaction record for Secretin at all — not against Phenylephrine, and not against any other medication we track. This verdict therefore rests on the absence of any recorded data, not on research that looked at this combination and found nothing. We cannot rule an interaction out.

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.

Secretin safety at a glance

Secretin overall Use caution Secretin is a prescription injectable given only by trained healthcare providers, not a self-care supplement.
Pregnancy Not established Safety during pregnancy is not well established; use only if a doctor decides the benefit outweighs the risk.
Breastfeeding Not established It is not known whether secretin is safe during breastfeeding, so caution is advised.

Safety guidance is general; always confirm with your pharmacist or doctor for your situation.

Still wondering about combining Phenylephrine and Secretin? Ask Dr. Brian Staiger, PharmD, BCPS directly ›
What to actually watch for

No Interaction Found — But Data Suggests Secretin and Phenylephrine 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.

  • Nausea reported in 7.6% of FDA reports for Phenylephrine Additional detail

    Secretin

    “Intravenously, secretin might cause abdominal pain, nausea, vomiting, and diarrhea. Secretin has also been linked with the development of pancreatitis.”

    Secretin · Natural Medicines adverse-effect record, reported in diarrhea.

    4 sources cited
    1. 6007. Secretin for the treatment of autism. Pharmacist's Letter/Prescriber's Letter 1998;14(12):141212.
    2. 7052. Roberts W, Weaver L, Brian J, et al. Repeated doses of porcine secretin in the treatment of autism: A randomized, placebo-controlled trial. Pediatrics 2001;107:e71. PubMed
    3. 106325. Brandler J, Miller LJ, Wang XJ, et al. Secretin effects on gastric functions, hormones and symptoms in functional dyspepsia and health: randomized crossover trial. Am J Physiol Gastrointest Liver Physiol 2020;318(4):G635-G645. PubMed
    4. 100741. Law R, Vargo JJ, Stevens T. Acute pancreatitis and aspiration pneumonia after administration of synthetic human secretin (with video). Gastrointest Endosc. 2011;74(5):1166-8. PubMed

    Phenylephrine

    Listed in the ADVERSE REACTIONS section of the FDA label for Phenylephrine, and in voluntary FDA adverse-event reports. Read the label on DailyMed ›

  • Vomiting Additional detail

    Secretin

    “Intravenously, the most common adverse reaction to secretin is flushing of the face, neck, and chest immediately after infusion. Less common potential adverse effects are vomiting, diarrhea, fainting, venous thrombosis (15), fever, and tachycardia. Some patients can have allergic reactions including urticaria, erythema, and anaphylaxis.”

    Secretin · Natural Medicines adverse-effect record, reported in diarrhea.

    4 sources cited
    1. 6007. Secretin for the treatment of autism. Pharmacist's Letter/Prescriber's Letter 1998;14(12):141212.
    2. 7052. Roberts W, Weaver L, Brian J, et al. Repeated doses of porcine secretin in the treatment of autism: A randomized, placebo-controlled trial. Pediatrics 2001;107:e71. PubMed
    3. 15. McEvoy GK, ed. AHFS Drug Information. Bethesda, MD: American Society of Health-System Pharmacists, 1998.
    4. 100741. Law R, Vargo JJ, Stevens T. Acute pancreatitis and aspiration pneumonia after administration of synthetic human secretin (with video). Gastrointest Endosc. 2011;74(5):1166-8. PubMed

    Phenylephrine

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

Reported for Secretin but not commonly for Phenylephrine: an allergic reaction, blood clots, stomach pain and pancreatitis.

Effects for Phenylephrine come from the ADVERSE REACTIONS section of its FDA label; effects for Secretin come from the Natural Medicines adverse-effect record, quoted above. Where a percentage is shown, it is the share of 221,388 voluntary FDA FAERS reports for Phenylephrine that mention that effect — a reporting proportion, not an incidence rate and not evidence the drug caused it. Wording is matched across sources by our own clinical vocabulary, so treat this as a prompt to pay attention, not a diagnosis.

From our Q&A

Questions About Secretin 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 Secretin 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 Secretin 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 Secretin 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 Secretin
Steady interest

#1,399 of 1,452 supplements looked up here in the last 7 days

29 days ago today
Medication Phenylephrine
Top 25%

#566 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 Secretin reference on this page ↓
  • Freshness: we automatically re-check this combination every week — this pair was last verified October 4, 2026. The Secretin and Phenylephrine records this page draws on were last updated July 10, 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 Secretin

What is Secretin?

  • Diagnostic testing of pancreas function
  • Diagnosing gastrinoma (Zollinger-Ellison syndrome)
  • Aiding pancreatic imaging procedures
  • Investigational use in autism (not proven)

Secretin is a natural digestive hormone, not a typical dietary supplement. As a medicine it is an FDA-approved injectable used mainly for diagnostic tests of the pancreas, and it must be given by a healthcare professional. Despite past interest, there is strong evidence that secretin does NOT help autism, and it should never be self-administered.

Hormone produced naturally in the small intestine; pharmaceutical versions are made synthetically or from animal sources · Injectable solution (prescription, used in medical settings)

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

Secretin: dosing

There is no general supplement dose for secretin because it is not used as a supplement. It is a prescription injectable, and the dose is calculated by your healthcare provider based on your body and the specific test being done.You should never try to obtain or self-administer secretin. Dosing, timing, and monitoring are all handled by trained medical staff during a procedure.

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

Read the full Secretin 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 several different products, and each one has its own use.

Injection (IV): raises blood pressure in adults with clinically important hypotension (low blood pressure) caused mainly by widened blood vessels. Some injections are labeled for anesthesia only. Others are labeled for anesthesia and septic shock.

Eye drops: Phenylephrine Hydrochloride Ophthalmic Solution is used to dilate the pupil.

Nasal products: temporarily relieve nasal and sinus congestion from the common cold, hay fever or other upper respiratory allergies.

Rectal suppositories: relieve itching, burning and discomfort from hemorrhoids and temporarily shrink hemorrhoidal tissue.

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 & Secretin

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

0Major
0Moderate
0Minor
2,829No known interaction
2,829 No interaction
No interaction 2,829 drugs checked — show the list

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

Showing the 60 most looked-up of 2,829 medications checked with no known interaction — see the full Secretin list.

See the full Secretin interactions page
See every supplement checked against Phenylephrine, ranked by severity
Evidence & sources

Secretin References

The 14 references that drive our Secretin 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. McEvoy GK, ed. AHFS Drug Information. Bethesda, MD: American Society of Health-System Pharmacists, 1998.
  2. Horvath K, Stefatos G, Sokolski KN. Improved social and language skills after secretin administration. J Assoc Acad Minor Phys 1998;9:9-15.
  3. Tympner F, Rosch W. The treatment of chronic recurrent pancreatitis with depot secretin-a preliminary report. Hepatogastroenterology 1986;33:159-62.
  4. Coniglio SJ, Lewis JD, Lang C, et al. A randomized, double-blind, placebo-controlled trial of single-dose intravenous secretin as treatment for children with autism. J Pediatr 2001;138:649-55. PubMed
  5. Secretin for the treatment of autism. Pharmacist's Letter/Prescriber's Letter 1998;14(12):141212.
  6. Sandler AD, Sutton KA, DeWeese J, et al. Lack of benefit of a single dose of synthetic human secretin in the treatment of autism and pervasive developmental disorder. N Engl J Med 1999;341(24):1801-6. PubMed
  7. Lightdale JR, Hayer C, Duer A, et al. Effects of intravenous secretin on language and behavior of children with autism and gastrointestinal symptoms: a single-blinded, open-label pilot study. Pediatrics 2001;108:90. PubMed
  8. Roberts W, Weaver L, Brian J, et al. Repeated doses of porcine secretin in the treatment of autism: A randomized, placebo-controlled trial. Pediatrics 2001;107:e71. PubMed
  9. Honomichl RD, Goodlin-Jones BL, Burnham MM, Hansen RL, Anders TF. Secretin and sleep in children with autism. Child Psychiatry Hum Dev. 2002;33(2):107-23. PubMed
  10. Law R, Vargo JJ, Stevens T. Acute pancreatitis and aspiration pneumonia after administration of synthetic human secretin (with video). Gastrointest Endosc. 2011;74(5):1166-8. PubMed
  11. Sheitman BB, Knable MB, Jarskog LF, et al. Secretin for refractory schizophrenia. Schizophr Res. 2004;66(2-3):177-81. PubMed
  12. Levenick JM, Andrews CL, Purich ED, Gordon SR, Gardner TB. A phase II trial of human secretin infusion for refractory type B pain in chronic pancreatitis. Pancreas. 2013;42(4):596-600. PubMed
  13. Williams K, Wray JA, Wheeler DM. Intravenous secretin for autism spectrum disorders (ASD). Cochrane Database Syst Rev. 2012;2012(4):CD003495. PubMed
  14. Brandler J, Miller LJ, Wang XJ, et al. Secretin effects on gastric functions, hormones and symptoms in functional dyspepsia and health: randomized crossover trial. Am J Physiol Gastrointest Liver Physiol 2020;318(4):G635-G645. PubMed

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 Secretin and Phenylephrine Together: Common Questions

Is it safe to take Secretin with Phenylephrine?
We do not list a known interaction between Secretin 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.
Do Secretin and Phenylephrine 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.
Does Phenylephrine interact with any supplements?
Yes. Phenylephrine has documented interactions with 81 supplements in our database — Secretin 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

Secretin 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

Still Have a Question About Phenylephrine and Secretin?

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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.