Kaolin + Sulfamethoxazole, Trimethoprim
Sulfamethoxazole, Trimethoprim brand names: Bactrim, Bactrim DS, Cotrim DS, Septra, Septra DS, and others.
Kaolin has a moderate interaction with Sulfamethoxazole, Trimethoprim. Kaolin may reduce the absorption of trimethoprim.
Read the full interaction reportKaolin and Sulfamethoxazole, Trimethoprim
Here is the interaction we found between these two, with the evidence behind it.
TRIMETHOPRIM (Proloprim)
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..
Here's the simple version: kaolin is a clay that works by soaking things up in your gut. The trouble is, it doesn't only bind to extra fluid, it can also grab onto medicines sitting in your stomach and intestines. With Bactrim (sulfamethoxazole/trimethoprim), studies suggest kaolin can latch onto the trimethoprim part and keep some of it from being absorbed into your body.
Why does that matter? Less of the antibiotic getting in means weaker blood levels, and an infection that doesn't clear the way it should. This isn't about more side effects, it's about the medicine possibly underperforming. The easy fix is timing: take your Bactrim and any kaolin product at least 3 hours apart. If you're unsure how to space them, your pharmacist can map it out for you.
- 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.
- 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.
Clinically significant. Avoid the combination, or use only under close professional supervision.
Usually worth avoiding or managing — may need monitoring, a dose change, or timing apart.
Generally not serious. Be aware of it and mention it to your pharmacist.
- 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.
- 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.
Kaolin Also Interacts With Other Medications
Kaolin has 6 moderate known drug interactions in our database — the Sulfamethoxazole, Trimethoprim one above is one of them. If you take anything else, check it against the full list below.
Check Another of Your Medications Against Kaolin
We haven’t checked that one against Kaolin yet — ask our pharmacists directly.
Covers the 2,830 medications we’ve checked against Kaolin. Pick one to open its full report.
See Every Supplement That Interacts With Sulfamethoxazole, Trimethoprim
This page covers Kaolin only. If you take other supplements — a multivitamin, a sleep aid, something for joints — the Sulfamethoxazole, Trimethoprim page lists 174 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), Beer (major) and Cesium (major).
By severity: 11 major · 139 moderate · 24 minor.
From our pharmacist’s overview on the Sulfamethoxazole, Trimethoprim page
“The supplement I check first with sulfamethoxazole and trimethoprim (Bactrim, Septra) is PABA, because it feeds bacteria the exact compound this antibiotic works by blocking and can cancel the treatment outright. It is one of 11 major-rated entries among 174 supplements and herbs on file here, a count that calls for genuine care.”
Reviewed by 2 · Jul 18, 2026
Where Kaolin and Sulfamethoxazole, 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.
#1,201 of 1,452 supplements looked up here in the last 7 days
#1,273 of 2,830 medications looked up here in the last 7 days
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.
About Kaolin
What is 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.
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.
No drugs match “”.
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.
- Apixaban ›
- Levothyroxine ›
- Amlodipine ›
- Methylphenidate ›
- Warfarin ›
- Sertraline ›
- Testosterone ›
- Losartan Potassium ›
- Metoprolol ›
- Aspirin ›
- Ivermectin ›
- Rivaroxaban ›
- Rosuvastatin ›
- Escitalopram ›
- Tadalafil ›
- Acetaminophen ›
- Clopidogrel ›
- Valacyclovir ›
- Atorvastatin ›
- Docusate ›
- Hydroxyurea ›
- Abemaciclib ›
- Methamphetamine ›
- Ibuprofen ›
- Sumatriptan ›
- Semaglutide ›
- Tirzepatide ›
- Warfarin Sodium ›
- Prednisone ›
- Propranolol ›
- Lisdexamfetamine ›
- Acyclovir ›
- Bupropion ›
- Metformin ›
- Amoxicillin ›
- Lisinopril ›
- Bendamustine ›
- Amitriptyline ›
- Doxycycline ›
- Lamotrigine ›
- Fluoxetine ›
- Methotrexate ›
- Acetaminophen, Codeine ›
- Gabapentin ›
- Amphetamine ›
- Pregabalin ›
- Isotretinoin ›
- Dextroamphetamine ›
- Azithromycin ›
- Clonazepam ›
- Quetiapine ›
- Omeprazole ›
- Amlodipine Besylate ›
- Methylene Blue ›
- Duloxetine ›
- Letrozole ›
- Buspirone ›
- Citalopram ›
- Ciprofloxacin ›
- Naproxen ›
Showing the 60 most looked-up of 2,823 medications checked with no known interaction — see the full Kaolin list.
Sources & How We Checked
Interaction details are evidence-graded and sourced from the Natural Medicines database. The medication overview comes from MedlinePlus.
- Natural Medicines (Therapeutic Research Center) — Evidence-graded clinical reference for vitamins, herbs and supplements — the basis for our interaction data.
- MedlinePlus, U.S. National Library of Medicine — NIH consumer drug information, used for the medication overviews.
- NIH Dietary Supplement Label Database (DSLD) — Official supplement product labels.
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
Sulfamethoxazole, Trimethoprim Is Linked to Lower Levels of 7 Nutrients
Natural Medicines records Sulfamethoxazole, Trimethoprim as a medicine that can lower these. This is not an interaction with Kaolin — it is a separate effect of the medicine, and it is a reason some people are advised to supplement rather than to avoid one:
Read the full Sulfamethoxazole, Trimethoprim nutrient depletion report ›
Depletion records come from the licensed Natural Medicines database. Do not start a supplement on the strength of this page — ask your pharmacist or doctor whether it applies to you.
Taking Kaolin and Sulfamethoxazole, Trimethoprim Together: Common Questions
Can you take Kaolin with Sulfamethoxazole, Trimethoprim?
How serious is the Kaolin and Sulfamethoxazole, Trimethoprim interaction?
Written and reviewed by the HelloPharmacist editorial staff. Our editorial policy
Still Have a Question About Sulfamethoxazole, Trimethoprim and Kaolin?
Our pharmacists answer your medication & supplement questions — free.
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.