Drug & supplement interaction

Kaolin + Sulfadiazine, Trimethoprim

Sulfadiazine, Trimethoprim brand name: Coptin.

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

Kaolin has a moderate interaction with Sulfadiazine, Trimethoprim. Kaolin may reduce the absorption of trimethoprim.

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

Kaolin and Sulfadiazine, Trimethoprim

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

Moderate

TRIMETHOPRIM (Proloprim)

Kaolin may reduce the absorption of trimethoprim. To avoid a potential interaction, separate trimethoprim and kaolin doses by at least 3 hours.
Severity Moderate Likelihood Probable Evidence B

Interaction 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..

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

Here's the thing about Kaolin: it's a clay-based adsorbent, which means it acts like a sponge in your gut and can grab onto medicines sitting nearby. With your combo product (the trimethoprim part especially), Kaolin can bind to it and keep some of it from being absorbed into your bloodstream. The worry isn't more side effects, it's the opposite. If less of the antibiotic gets in, you may not get the full punch you need to clear an infection like a UTI.

The good news is this is easy to manage. Just space the doses out, taking your Sulfadiazine/Trimethoprim at least 3 hours apart from any Kaolin product. If you're treating an active infection, run it by your pharmacist or doctor so your medicine works the way it should.

Contact Dr. Brian directly if you have additional questions on this interaction
References
  1. Babhair SA, Tariq M. Effect of magnesium trisilicate and kaolin-pectin on the bioavailability of trimethoprim. Res Commun Chem Pathol Pharmacol 1983;40:165-8.
  2. Electronic Code of Federal Regulations. Title 21. Part 335 - Antidiarrheal drug products for over-the-counter human use. Available at: https://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfcfr/CFRSearch.cfm?fr=335.50

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

Kaolin Also Interacts With Other Medications

Kaolin has 6 moderate known drug interactions in our database — the Sulfadiazine, Trimethoprim one above is one of them. If you take anything else, check it against the full list below.

Moderate 6 No known interaction 2,824 (incl. Sulfadiazine, Trimethoprim)
Taking anything else?

Check Another of Your Medications Against Kaolin

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

Everything else you take

See Every Supplement That Interacts With Sulfadiazine, Trimethoprim

This page covers Kaolin only. If you take other supplements — a multivitamin, a sleep aid, something for joints — the Sulfadiazine, Trimethoprim page lists 63 supplements it has a documented interaction with, worst first, each one explained.

The most serious there right now: Activated Charcoal (major), American Hellebore (major), Arsenic (major), Cesium (major) and Ephedra (major).

By severity: 8 major · 44 moderate · 11 minor.

From our pharmacist’s overview on the Sulfadiazine, Trimethoprim page

“Sulfadiazine with trimethoprim (Coptin) earns more wariness than most antibiotics do, and the eight major-rated interactions on this list of 63 are the ones to understand first. Most of them share a single mechanism.”

Reviewed by 2 · Jul 18, 2026

Open the Sulfadiazine, Trimethoprim interaction page

How much people look this up

Where Kaolin and Sulfadiazine, Trimethoprim 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 Kaolin
Steady interest

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

29 days ago today
Medication Sulfadiazine, Trimethoprim
Top half

#1,296 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 Kaolin

What is Kaolin?

Kaolin
  • Diarrhea
  • Upset stomach and nausea
  • Skincare and facial masks
  • Soothing minor skin irritation
  • Excessive salivation (traditional)

Kaolin is a soft, white clay mineral that has long been used in antidiarrheal products and skincare because it absorbs water and binds substances in the gut. Older diarrhea products often combined it with pectin, but modern guidelines favor rehydration and other treatments, and high-quality evidence for kaolin alone is limited. It is generally considered low-risk for short-term use, but check with your pharmacist or doctor before use, especially during pregnancy or breastfeeding.

Read the full Kaolin monograph & all interactions
Keep checking

Other Drugs & Kaolin

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

0Major
6Moderate
0Minor
2,823No known interaction
6 Moderate 2,823 No interaction
Moderate

6 interactions

No interaction 2,823 drugs checked — show the list

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

Showing the 60 most looked-up of 2,823 medications checked with no known interaction — see the full Kaolin list.

See the full Kaolin interactions page
See every supplement checked against Sulfadiazine, Trimethoprim, 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
Kaolin monograph › Uses, safety, and every drug interaction in one place Sulfadiazine, Trimethoprim supplement interactions › Every supplement checked against Sulfadiazine, Trimethoprim, 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

Taking Kaolin and Sulfadiazine, Trimethoprim Together: Common Questions

Can you take Kaolin with Sulfadiazine, Trimethoprim?
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 Kaolin and Sulfadiazine, Trimethoprim 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 Sulfadiazine, Trimethoprim and Kaolin?

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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.