Drug & supplement interaction

Oxygen Therapy + Phenylephrine

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

No Known Interaction
Medically reviewed by · Updated June 2026 · Pair last verified Oct 4, 2026
The bottom line No known interaction

We found no known interaction between Oxygen Therapy 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

Oxygen Therapy 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 Oxygen Therapy in our sources. This does not guarantee that the combination is completely free of risk — research on Oxygen Therapy alongside specific medications may be limited.

Worth understanding: our licensed dataset holds no drug-interaction record for Oxygen Therapy 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.

Oxygen Therapy is a treatment rather than something you take. Tell whoever provides it which medicines you use, and ask your prescriber whether it is appropriate for your health and treatment. 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.

Oxygen Therapy safety at a glance

Oxygen Therapy overall Use caution Medical oxygen is safe and lifesaving when prescribed, but it is a drug that can cause harm if used without proper testing and monitoring.
Pregnancy Use caution Supplemental oxygen may be used in pregnancy when medically needed, but only under a doctor's supervision.
Breastfeeding Use caution Use only as directed by a healthcare provider; medical oxygen does not pass into milk, but the underlying condition needs proper care.

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

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

What Phenylephrine’s Own FDA Label Lists

This is not an interaction — none of it involves Oxygen Therapy. These are the most notable effects listed in the ADVERSE REACTIONS section of Phenylephrine’s own FDA label, for the medication by itself. Knowing the drug’s own list makes it easier to work out the likely cause if something new turns up while you have Oxygen Therapy and take the medicine. 3 of them are worth acting on rather than waiting out — marked below.

  • A slow heartbeat Worth acting on
  • Shortness of breath Worth acting on mentioned in 6.2% of FDA reports for Phenylephrine
  • Raised blood pressure Worth acting on
  • Blurred vision
  • Headache mentioned in 7.8% of FDA reports for Phenylephrine
  • Nausea mentioned in 7.6% of FDA reports for Phenylephrine
  • Vomiting

From the ADVERSE REACTIONS section of the FDA label for Phenylephrine. Read the label on DailyMed › 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. Oxygen Therapy’s licensed record lists no adverse effects our clinical vocabulary could match, so there is no Oxygen Therapy side to compare — that is a limit of the record, not a statement that Oxygen Therapy has no side effects.

From our Q&A

Questions About Oxygen Therapy 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 Oxygen Therapy 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 Oxygen Therapy 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 Oxygen Therapy 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 Oxygen Therapy
Steady interest

#1,231 of 1,452 supplements looked up here in the last 7 days

29 days ago today
Medication Phenylephrine
Top 25%

#668 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. Oxygen Therapy is not yet covered by that licensed database, so its write-up cites publicly available medical sources directly (see the references below).
  • Citation library: 103,510 references behind our interaction content, 65,311 of them resolved to verified PubMed/DOI sources. See every Oxygen Therapy reference on this page ↓
  • Freshness: we automatically re-check this combination every week — this pair was last verified October 4, 2026. The Oxygen Therapy and Phenylephrine records this page draws on were last updated June 20, 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 .
Treatment approach

About Oxygen Therapy

What is Oxygen Therapy?

  • Low blood oxygen from lung disease (COPD)
  • Severe COVID-19 or pneumonia
  • Hyperbaric treatment of wounds and decompression sickness
  • Carbon monoxide poisoning
  • Cluster headaches
  • Marketed for 'energy,' altitude, or general wellness

Oxygen therapy is a real medical treatment that gives extra oxygen to people whose blood oxygen is low, and it can be lifesaving when prescribed and monitored by a healthcare provider. It is not a dietary supplement, and using too much oxygen or relying on unproven 'oxygen' wellness products can be harmful or simply ineffective. Always use oxygen only under medical guidance.

Medical oxygen gas (nasal cannula, face mask, oxygen concentrator), hyperbaric oxygen chambers, and marketed 'oxygen' products such as canned oxygen, oxygenated water, and hydrogen peroxide drops

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

Oxygen Therapy: dosing

There is no single 'dose' of oxygen that fits everyone. Medical oxygen is prescribed and adjusted by a healthcare provider based on your blood oxygen levels, your condition, and your symptoms. It is usually measured as a flow rate (liters per minute) or a percentage of oxygen, and often guided by a fingertip oxygen monitor (pulse oximeter) or blood tests.Because the right amount is so individual, you should never change your oxygen flow or stop it on your own.

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

Read the full Oxygen Therapy 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 & Oxygen Therapy

Browse every other medication we’ve checked against Oxygen Therapy — 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 Oxygen Therapy 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 Oxygen Therapy list.

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

Oxygen Therapy References

The 2 sources that drive our Oxygen Therapy monograph — publicly available pages from reputable medical and government organizations. Every link was verified to work before publishing. Oxygen Therapy is not covered by the licensed Natural Medicines interaction database, so its page cites these public sources directly.

  1. Oxygen Therapy — MedlinePlus (U.S. National Library of Medicine) Source
  2. Oxygen Therapy — Cleveland Clinic Source

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

Having Oxygen Therapy While Taking Phenylephrine: Common Questions

Is it safe to have Oxygen Therapy while taking Phenylephrine?
We do not list a known interaction between Oxygen Therapy 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.
Does Phenylephrine interact with any supplements?
Yes. Phenylephrine has documented interactions with 81 supplements in our database — Oxygen Therapy 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

Oxygen Therapy 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 2 citations behind this page Ask a pharmacist Free, personal answer from our licensed team

Still Have a Question About Phenylephrine and Oxygen Therapy?

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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.