Drug & supplement interaction

Banderol + Valacyclovir

Valacyclovir brand name: Valtrex.

Moderate Interaction
Medically reviewed by · Updated February 2023
The bottom line Moderate

Banderol has a moderate interaction with Valacyclovir. Small lab studies have found that Banderol may inhibit OATP1B1 (Organic Anion Transporting Polypeptide 1B1), which is a membrane protein responsible for the uptake of various drugs, hormones, and other biologically active substances into the cells of the liver and other tissues.

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

Banderol and Valacyclovir

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

Moderate

ORGANIC ANION TRANSPORTER 1 (OAT1) SUBSTRATES

Why this applies to Valacyclovir

Valacyclovir falls under ORGANIC ANION TRANSPORTER 1 (OAT1) SUBSTRATES — the group Banderol interacts with.

Small lab studies have found that Banderol may inhibit OATP1B1 (Organic Anion Transporting Polypeptide 1B1), which is a membrane protein responsible for the uptake of various drugs, hormones, and other biologically active substances into the cells of the liver and other tissues. It is often referred to as a drug transporter. It is a member of the OATP family of transporters and is known to play a critical role in the pharmacokinetics of many drugs. When OATPs are inhibited, it can cause problems with the elimination of drugs and result in a sudden rise in the concentration of the drug in the bloodstream and the extent to which it is absorbed (AUC) for drugs that rely on these transporters. This can increase the likelihood of adverse side effects associated with the therapy.
Severity Moderate Likelihood Possible Evidence A

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 gist for Valtrex (valacyclovir). The concern on file is that Banderol may block a transporter that helps shuttle certain medicines into and out of your body. If a drug isn't cleared as efficiently, its level in the blood can climb, which can mean more side effects.

For valacyclovir specifically, higher levels could mean more headache, nausea, belly upset, or feeling tired, and at the kidneys it's worth being a little cautious since this drug is mostly cleared by the kidneys. That said, this is based only on small lab studies, not real-world cases, so I wouldn't lose sleep over it. Still, since you're on a defined course for shingles or herpes, it's smart to run the Banderol by your pharmacist or doctor first.

Contact Dr. Brian directly if you have additional questions on this interaction

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

Banderol Also Interacts With Other Medications

Banderol has 176 moderate known drug interactions in our database — the Valacyclovir one above is one of them. If you take anything else, check it against the full list below.

Moderate 176 No known interaction 2,654 (incl. Valacyclovir)
Taking anything else?

Check Another of Your Medications Against Banderol

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

From our Q&A

Questions About Banderol or Valacyclovir

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

This page covers Banderol only. If you take other supplements — a multivitamin, a sleep aid, something for joints — the Valacyclovir page lists 27 supplements it has a documented interaction with, worst first, each one explained.

The most serious there right now: Activated Charcoal (major), African Wild Potato (moderate), Biofeedback (moderate), Caffeic Acid (moderate) and Coffee Charcoal (moderate).

By severity: 1 major · 17 moderate · 9 minor.

From our pharmacist’s overview on the Valacyclovir page

“Valacyclovir (Valtrex) works against herpes outbreaks only if enough of it gets absorbed into your blood, and most of this list threatens exactly that. Of the 27 supplements on file, 17 can change how well oral medicines like this one are absorbed, and the single major-rated entry, activated charcoal, binds drugs in the gut outright.”

Reviewed by 2 · Jul 18, 2026

Open the Valacyclovir interaction page

How much people look this up

Where Banderol and Valacyclovir 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 Banderol
Steady interest

#1,089 of 1,452 supplements looked up here in the last 7 days

29 days ago today
Medication Valacyclovir
Top 5%

#73 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.

Supplement

About Banderol

What is Banderol?

Banderol
  • Lyme disease support
  • Antimicrobial
  • Antifungal
  • Immune support
  • Inflammation

Banderol is a Nutramedix-branded herbal extract made from the bark of the Amazonian tree Otoba parvifolia, most often promoted as part of alternative Lyme disease protocols. There is very little high-quality human research to support its use, so the evidence behind its benefits is weak and largely preliminary. Talk with your pharmacist or doctor before using it, and never use it to replace proven treatments.

Read the full Banderol monograph & all interactions
Medication

About Valacyclovir

What Is Valacyclovir Used For?

Brand name: Valtrex

Valacyclovir treats infections caused by herpes viruses. In adults, it is used for cold sores, genital herpes and shingles (herpes zoster).

For genital herpes, it treats first and repeat episodes, helps suppress repeat outbreaks, and reduces the chance of passing the infection to a partner. In children, it is used for cold sores (age 12 and older) and chickenpox (ages 2 to under 18), as listed on the Valtrex and valacyclovir tablet labels.

See full Valacyclovir drug information
Keep checking

Other Drugs & Banderol

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

0Major
176Moderate
0Minor
2,653No known interaction
176 Moderate 2,653 No interaction
Moderate

176 interactions

Showing 60 of 176 moderate interactions — see all 176 on the Banderol page.

No interaction 2,653 drugs checked — show the list

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

Showing the 60 most looked-up of 2,653 medications checked with no known interaction — see the full Banderol list.

See the full Banderol interactions page
See every supplement checked against Valacyclovir, 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

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Pharmacist Counseling Corner

Taking Banderol and Valacyclovir Together: Common Questions

Can you take Banderol with Valacyclovir?
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 Banderol and Valacyclovir 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 Valacyclovir and Banderol?

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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.