Drug & supplement interaction

Biofeedback + Acyclovir

Acyclovir brand names: Zovirax, Zovirax Injection, Sitavig, Avaclyr.

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

Biofeedback has a moderate interaction with Acyclovir. 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 Acyclovir

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

Moderate

SEIZURE THRESHOLD LOWERING DRUGS

Why this applies to Acyclovir

Acyclovir 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

Here's the short version: this isn't a typical drug interaction where one thing changes the levels of another. Biofeedback is a relaxation and self-control technique, not a pill, so it doesn't affect how your body absorbs or breaks down acyclovir. The note in our system is really about EEG biofeedback specifically, where there's a theoretical concern it could slightly lower the seizure threshold. Acyclovir, in rare cases (usually with high doses or in people with kidney problems), can also affect the nervous system and cause confusion or, very rarely, seizures.

The evidence here is weak and mostly theoretical, so for most people this is nothing to lose sleep over. Still, if you have a seizure history or kidney issues, it's worth a quick chat with your pharmacist or doctor before starting biofeedback.

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 Acyclovir 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. Acyclovir)
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.

From our Q&A

Questions About Biofeedback or Acyclovir

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

This page covers Biofeedback only. If you take other supplements — a multivitamin, a sleep aid, something for joints — the Acyclovir page lists 37 supplements it has a documented interaction with, worst first, each one explained.

The most serious there right now: Activated Charcoal (major), Asarabacca (major), Siberian Cocklebur (major), African Wild Potato (moderate) and Aristolochia (moderate).

By severity: 3 major · 23 moderate · 11 minor.

From our pharmacist’s overview on the Acyclovir page

“Kidney strain is the risk to understand first. Acyclovir (Zovirax) can stress the kidneys on its own, and a few ingredients here, Siberian cocklebur especially, are toxic to kidney tissue, so pairing them could compound the harm.”

Reviewed by 2 · Jul 18, 2026

Open the Acyclovir interaction page

How much people look this up

Where Biofeedback and Acyclovir 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 half

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

29 days ago today
Medication Acyclovir
Top 5%

#123 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
Medication

About Acyclovir

What Is Acyclovir Used For?

Brand names: Zovirax, Zovirax Injection, Sitavig, Avaclyr

Acyclovir treats infections caused by herpes-family viruses. Which uses apply depends on the product and how it is given.

Oral acyclovir (capsules, tablets and suspension) is used for shingles, genital herpes and chickenpox. Creams, ointments, an eye ointment, a buccal tablet and an IV form each cover narrower uses, described below.

See full Acyclovir drug information
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 Acyclovir, 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 Acyclovir supplement interactions › Every supplement checked against Acyclovir, ranked by severity Acyclovir drug information › The full plain-English guide to this medication 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 Acyclovir: Common Questions

Can you have Biofeedback while taking Acyclovir?
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 Acyclovir 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

Still Have a Question About Acyclovir and Biofeedback?

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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.