Drug & supplement interaction

Biofeedback + Codeine Phosphate, Guaifenesin

Codeine Phosphate, Guaifenesin brand names: Brontex, Robitussin AC.

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

Biofeedback has a moderate interaction with Codeine Phosphate, Guaifenesin. There is some concern that electroencephalogram (EEG) biofeedback might lower the seizure threshold in some patients.

Read the full interaction report
SeverityModerate
LikelihoodPossible
EvidenceB
What do Severity, Likelihood & Evidence mean?
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Interaction report

Biofeedback and Codeine Phosphate, Guaifenesin

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

Moderate

SEIZURE THRESHOLD LOWERING DRUGS

Why this applies to Codeine Phosphate, Guaifenesin

Codeine Phosphate, Guaifenesin falls under SEIZURE THRESHOLD LOWERING DRUGS — the group Biofeedback interacts with.

There is some concern that electroencephalogram (EEG) biofeedback might lower the seizure threshold in some patients. Theoretically, combining EEG biofeedback with seizure threshold-lowering drugs might increase the risk of seizure.
Some drugs that lower the seizure threshold include anesthetics (propofol, others), antiarrhythmics (mexiletine), antibiotics (amphotericin, penicillin, cephalosporins, imipenem), antidepressants (bupropion, others), antihistamines (cyproheptadine, others), immunosuppressants (cyclosporine), narcotics (fentanyl, others), stimulants (methylphenidate), theophylline, and others.
Severity Moderate Likelihood Possible Evidence B

Interaction 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.

Dr. Brian Staiger, PharmD, BCPS
Dr. Brian Staiger explains PharmD, Clinical Pharmacist

Let me put your mind at ease on this one. Biofeedback is a relaxation and body-awareness technique, not something your body has to break down, so it doesn't change how your liver processes the codeine in your cough syrup. There's no metabolism clash here.

The only theoretical note is that one specific type, EEG biofeedback, might slightly lower the seizure threshold in certain people. Codeine, like other narcotics, can also nudge that threshold down, especially at higher doses. So in theory, combining the two could make a seizure a touch more likely. This concern is small and not well proven. If you have epilepsy or a seizure history, it's worth a quick chat with your doctor before starting EEG biofeedback, but otherwise this is generally low risk.

Contact Dr. Brian directly if you have additional questions on this interaction
References
  1. Friel PN. EEG biofeedback in the treatment of attention deficit hyperactivity disorder. Altern Med Rev 2007;12:146-51.

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

Biofeedback Also Interacts With Other Medications

Biofeedback has 417 moderate known drug interactions in our database — the Codeine Phosphate, Guaifenesin one above is one of them. If you take anything else, check it against the full list below.

Moderate 417 No known interaction 2,413 (incl. Codeine Phosphate, Guaifenesin)
Taking anything else?

Check Another of Your Medications Against Biofeedback

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

Everything else you take

See Every Supplement That Interacts With Codeine Phosphate, Guaifenesin

This page covers Biofeedback only. If you take other supplements — a multivitamin, a sleep aid, something for joints — the Codeine Phosphate, Guaifenesin page lists 144 supplements it has a documented interaction with, worst first, each one explained.

The most serious there right now: 1,4-butanediol (major), Activated Charcoal (major), Beer (major), Gamma-hydroxybutyrate (ghb) (major) and Kava (major).

By severity: 7 major · 114 moderate · 23 minor.

Open the Codeine Phosphate, Guaifenesin interaction page

How much people look this up

Where Biofeedback and Codeine Phosphate, Guaifenesin 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 Biofeedback
Top 25%

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

29 days ago today
Medication Codeine Phosphate, Guaifenesin
Top half

#759 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.

Treatment approach

About Biofeedback

What is Biofeedback?

  • Chronic pain
  • Headaches and migraines
  • Anxiety and stress
  • High blood pressure
  • Urinary incontinence
  • Tension and muscle relaxation

Biofeedback is a mind-body technique, not an herb or supplement. It uses sensors to show you real-time information about body functions like heart rate, muscle tension, or skin temperature so you can learn to control them. It is generally very safe and has reasonable evidence for headaches, certain pain conditions, and pelvic floor problems, but it works best alongside standard medical care.

Read the full Biofeedback monograph & all interactions
Keep checking

Other Drugs & Biofeedback

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

0Major
417Moderate
0Minor
2,412No known interaction
417 Moderate 2,412 No interaction
Moderate

417 interactions

Showing 60 of 417 moderate interactions — see all 417 on the Biofeedback page.

No interaction 2,412 drugs checked — show the list

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

Showing the 60 most looked-up of 2,412 medications checked with no known interaction — see the full Biofeedback list.

See the full Biofeedback interactions page
See every supplement checked against Codeine Phosphate, Guaifenesin, 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
Biofeedback monograph › Uses, safety, and every drug interaction in one place Codeine Phosphate, Guaifenesin supplement interactions › Every supplement checked against Codeine Phosphate, Guaifenesin, 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 Ask a pharmacist › Free, personal answer from our licensed team
Pharmacist Counseling Corner

Having Biofeedback While Taking Codeine Phosphate, Guaifenesin: Common Questions

Can you have Biofeedback while taking Codeine Phosphate, Guaifenesin?
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 Biofeedback and Codeine Phosphate, Guaifenesin 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

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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.