Thiamine + Cefaclor
Cefaclor brand names: Ceclor CD, Ceclor.
We found no known interaction between Thiamine and Cefaclor in our sources. Absence of a documented interaction is not the same as proven safety, and does not guarantee one does not exist. Do not start, stop, or change a medication or supplement based on this page; confirm with your pharmacist or doctor first. Additionally, although there is no interaction, the label for Cefaclor states a food rule worth keeping to, and the two are separately associated with some of the same side effects, which would make a new symptom harder to attribute to one or the other.
Thiamine and Cefaclor
We checked these two against our interaction database. Here is what we found.
No Known Interaction Found
We did not find a documented interaction between Cefaclor and Thiamine in our sources. This does not guarantee that the combination is completely free of risk — there is often limited research on supplements and herbal products, especially around drug interactions.
If you decide to take both, the practical routine is simple: add one new thing at a time and note the date you started it. If the combination is going to disagree with you, it usually shows in the first days to a couple of weeks — and a start date turns “I’ve been feeling off” into something a pharmacist can actually work with. Do not stop a prescribed medicine on your own.
Always talk with your pharmacist or doctor before making changes to your medications or supplements, particularly if you take several medications or have an ongoing health condition.
Thiamine safety at a glance
Pregnancy & breastfeeding ratings are from Natural Medicines (Therapeutic Research Center) — the full detail is in the Special populations card below. Safety guidance is general; always confirm with your pharmacist or doctor for your situation.
Why No Interaction Is Listed for Cefaclor
Interactions in our licensed database are recorded against drug classes, not just single drug names. Cefaclor is filed under 6 classifications — including organic anion transporter 3 (oat3) substrates, organic anion transporter 1 (oat1) substrates, antibiotic drugs. Thiamine has documented interactions with 1 drug class — the most serious being trimethoprim (proloprim) (minor) — and none of Cefaclor’s classifications are among them.
Classification data comes from our licensed Natural Medicines dataset. A medication can belong to classes beyond those recorded there, so this describes how the check was run — it is not a safety guarantee.
Thiamine Does Interact With Other Medications
Thiamine has 3 minor known drug interactions in our database — Cefaclor isn’t one of them. If you take anything else, check it against the full list below.
Check Another of Your Medications Against Thiamine
We haven’t checked that one against Thiamine yet — ask our pharmacists directly.
Covers the 2,830 medications we’ve checked against Thiamine. Pick one to open its full report.
Thiamine in Pregnancy & Breastfeeding
When used orally in dietary amounts of 1.4 mg daily. A tolerable upper intake level (UL) has not been established for healthy individuals.
DISCLAIMER: This tool is intended for informational purposes only, and should not be interpreted as specific medical advice. Patients should consult with a qualified healthcare provider before making decisions about therapies and/or health conditions.© 2026 Therapeutic Research Center
No Interaction — But Cefaclor May Lower Your Thiamine Levels
These two do not interact. The relationship runs the other way: the licensed record lists Cefaclor as associated with lower Thiamine levels — rated “Insignificant Depletion”.
Theoretically, antibiotics might reduce thiamine absorption; however, this is not likely to be clinically significant. Interference with the normal gastrointestinal flora by antibiotics may reduce bacterial synthesis of thiamine. However, the majority of the daily thiamine requirement is obtained from the diet, rather than synthesis by the GI flora. Therefore this isn't likely to be clinically significant, and thiamine supplements aren't necessary.
THIAMINE — Insignificant Depletion
See every medication linked to lower Thiamine levels · See the full Cefaclor nutrient report
Disclaimer: This checker finds which nutrients might be depleted by prescription or over-the-counter medications. Each nutrient depletion issue is rated based on clinical significance. Use your own professional judgment prior to making clinical decisions.© 2026 Therapeutic Research Center
Some Cefaclor Products Have a Food Rule — Thiamine Should Not Break It
At least one FDA label for a product containing Cefaclor says to take it with food. If you take Thiamine on an empty stomach out of habit, keep them separate — and take Cefaclor with a meal where the label says to.
This may not be true of your version. Food instructions belong to the product, not the ingredient: two Cefaclor products can carry different directions, and extended-release forms often differ from immediate-release ones. The label we read is quoted below — check the directions on your own box or bottle, or ask your pharmacist, for how to take the exact product you were given.
DOSAGE AND ADMINISTRATION The absorption of cefaclor extended-release tablets is enhanced when it is administered with food.
From the Dosage and Administration section of the FDA label we read for Cefaclor — where that label names a specific product, the instruction is that product's. Read the label on DailyMed ›
A food rule is not an interaction — it is about how much of the medicine you absorb. The directions that came with your own product, and your pharmacist, outrank anything on this page.
What Cefaclor Is Prescribed For, and What Thiamine Has Been Studied For
These two come up together because they touch the same health topic — not because they do the same job. Cefaclor is a prescription medicine with approved uses on its FDA label. Thiamine is a supplement: what follows is what researchers have looked at it for, and how strong that evidence is.
Cefaclor is prescribed for: Cefaclor treats a range of bacterial infections. The capsule and oral suspension forms are used for ear infections (otitis media), lower respiratory tract infections including pneumonia, strep throat and tonsillitis, urinary tract infections (including kidney infections and bladder infections), and skin and skin structure infections. The extended-release tablet form of Cefaclor is approved for a narrower set of uses: acute bacterial flare-ups of chronic bronchitis, strep throat and tonsillitis, and uncomplicated skin infections. Not all infections approved for the capsule or suspension are approved for the extended-release tablet — your prescriber will choose the right form for your infection.
Thiamine has been studied for:
-
Pneumonia studied, not established Thiamine has been studied for this. Natural Medicines rates the evidence: Insufficient Reliable Evidence To Rate Read what the research shows
Thiamine for pneumonia
It is unclear if thiamine is beneficial for patients with pneumonia.
Effectiveness ratings and the research summaries above are the verbatim record from the Natural Medicines database, which grades evidence from “Effective” down to “Insufficient Reliable Evidence To Rate”. A rating below the top of that scale means researchers have looked at it — not that it works, and never that it can stand in for a prescribed medicine. Do not stop or replace Cefaclor on your own; if you are taking Thiamine for the same health topic, tell your prescriber, especially if the medicine is being adjusted to a target.
See Every Supplement That Interacts With Cefaclor
This page covers Thiamine only. If you take other supplements — a multivitamin, a sleep aid, something for joints — the Cefaclor page lists 60 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 · 46 moderate · 11 minor.
From our pharmacist’s overview on the Cefaclor page
“The entries worth understanding before any others on this cefaclor (Ceclor) page are the kidney risks and charcoal. Cefaclor is a cephalosporin antibiotic, typically a short course for ear, sinus, throat, or skin infections, and two herbs here, Siberian cocklebur and asarabacca, can damage the kidneys on their own, so pairing either wi…”
Reviewed by 2 · Jul 18, 2026
Taking Thiamine as Part of a Dietary Supplement Product? Check It for Interactions
We hold 3 real supplement products containing Thiamine, each one broken down to its full ingredient list — and combination products often carry several ingredients besides Thiamine. Even though Thiamine itself has no known interaction with Cefaclor, another ingredient on your label might. Find your product and we’ll check every ingredient on its label:
Where Thiamine and Cefaclor 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.
#164 of 1,452 supplements looked up here in the last 7 days
#227 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.
Where does our data come from?
- Source: the Natural Medicines (TRC Healthcare) clinical database — the evidence-graded professional reference for herb & supplement interactions.
- Citation library: 103,510 references behind our interaction content, 65,311 of them resolved to verified PubMed/DOI sources. See every Thiamine reference on this page ↓
- Freshness: we automatically re-check this combination every week — this pair was last verified October 4, 2026. The Thiamine and Cefaclor records this page draws on were last updated July 10, 2026.
- What “no known interaction” means: no documented interaction in the sources above — not a guarantee of safety. Supplements are studied far less than prescription drugs, so we say exactly what the evidence supports, and nothing more.
About Thiamine
What is Thiamine?
- Preventing or treating thiamine deficiency
- Beriberi
- Wernicke-Korsakoff syndrome (alcohol-related)
- Supporting energy and nerve function
- General B-vitamin supplementation
Thiamine (vitamin B1) is an essential nutrient your body needs to turn food into energy and to keep your nerves and heart healthy. Most people get enough from food, but supplements are clearly useful for deficiency, certain medical conditions, and people with heavy alcohol use. Talk with your pharmacist or doctor before starting it, especially if you have a chronic illness.
Tablets, capsules, oral liquids, injectable solutions (prescription), part of B-complex and multivitamins
An interaction check asks whether these two react with each other — it does not ask whether Thiamine is a good idea for someone in your situation. Here is what our Thiamine record says about it on its own.
Thiamine: dosing
The right dose of thiamine depends on your age, health, and the reason you are taking it. There is a recommended daily intake for general nutrition, and higher amounts are sometimes used by doctors to treat a deficiency.For supplements, the best approach is to follow the directions on the product label and not exceed them without guidance.
From our Thiamine monograph — the full record covers uses, side effects and every documented interaction.
About Cefaclor
What Is Cefaclor Used For?
Brand names: Ceclor CD, Ceclor
Cefaclor treats a range of bacterial infections. The capsule and oral suspension forms are used for ear infections (otitis media), lower respiratory tract infections including pneumonia, strep throat and tonsillitis, urinary tract infections (including kidney infections and bladder infections), and skin and skin structure infections.
The extended-release tablet form of Cefaclor is approved for a narrower set of uses: acute bacterial flare-ups of chronic bronchitis, strep throat and tonsillitis, and uncomplicated skin infections. Not all infections approved for the capsule or suspension are approved for the extended-release tablet — your prescriber will choose the right form for your infection.
Most-Reported Side Effects for Cefaclor
From FAERS, the FDA’s public side-effect reporting system (1,535 reports, all brands). Reports are voluntary and are not proof the drug caused the effect.
Other Drugs & Thiamine
Browse every other medication we’ve checked against Thiamine — both the ones with a known interaction and the ones without. Select any drug for the full detail.
No drugs match “”.
3 interactions
No interaction 2,826 drugs checked — show the list
We also checked Thiamine against these medications and found no known interaction in our sources. Open any page to confirm.
- Apixaban ›
- Levothyroxine ›
- Amlodipine ›
- Methylphenidate ›
- Warfarin ›
- Ivermectin ›
- Abemaciclib ›
- Testosterone ›
- Losartan Potassium ›
- Sertraline ›
- Acetaminophen ›
- Rosuvastatin ›
- Aspirin ›
- Metoprolol ›
- Escitalopram ›
- Clopidogrel ›
- Atorvastatin ›
- Rivaroxaban ›
- Isotretinoin ›
- Tirzepatide ›
- Ibuprofen ›
- Warfarin Sodium ›
- Amlodipine Besylate ›
- Levothyroxine, Liothyronine ›
- Docusate ›
- Methamphetamine ›
- Prednisone ›
- Metformin ›
- Amitriptyline ›
- Tadalafil ›
- Semaglutide ›
- Lisdexamfetamine ›
- Hydroxyurea ›
- Valacyclovir ›
- Amphetamine ›
- Sumatriptan ›
- Propranolol ›
- Methotrexate ›
- Lisinopril ›
- Amoxicillin ›
- Bupropion ›
- Fluoxetine ›
- Azithromycin ›
- Pregabalin ›
- Doxycycline ›
- Gabapentin ›
- Acetaminophen, Aspirin, Caffeine ›
- Dextroamphetamine ›
- Naproxen ›
- Lamotrigine ›
- Bendamustine ›
- Quetiapine ›
- Clonazepam ›
- Acyclovir ›
- Buspirone ›
- Duloxetine ›
- Omeprazole ›
- Letrozole ›
- Citalopram ›
- Methylene Blue ›
Showing the 60 most looked-up of 2,826 medications checked with no known interaction — see the full Thiamine list.
Thiamine References
The 7 references that drive our Thiamine monograph and interaction data, from the evidence-graded Natural Medicines (TRC Healthcare) database. Citations with a link open the study on PubMed or the publisher’s site.
- McEvoy GK, ed. AHFS Drug Information. Bethesda, MD: American Society of Health-System Pharmacists, 1998.
- Yates AA, Schlicker SA, Suitor CW. Dietary reference intakes: The new basis for recommendations for calcium and related nutrients, B vitamins, and choline. J Am Diet Assoc 1998;98:699-706. PubMed
- Food and Nutrition Board, Institute of Medicine. Dietary Reference Intakes for Thiamin, Riboflavin, Niacin, Vitamin B6, Folate, Vitamin B12, Pantothenic Acid, Biotin, and Choline (2000). Washington, DC: National Academy Press, 2000. Available at: http://b
- Rogovik, A. L., Vohra, S., and Goldman, R. D. Safety considerations and potential interactions of vitamins: should vitamins be considered drugs? Ann.Pharmacother. 2010;44(2):311-324. PubMed
- Arruti N, Bernedo N, Audicana MT, Villarreal O, Uriel O, Muñoz D. Systemic allergic dermatitis caused by thiamine after iontophoresis. Contact Dermatitis. 2013 Dec;69(6):375-6. PubMed
- Thiamine hydrochloride injection package insert. Lake Zurich, IL: Fresenius Kabi, LLC; September 2019.
- Vora B, Wen A, Yee SW, et al. The Effect of Trimethoprim on Thiamine Absorption: A Transporter-Mediated Drug-Nutrient Interaction. Clin Pharmacol Ther 2023;114(2):381-392.
Medication overviews come from MedlinePlus (NIH); supplement label data from the NIH Dietary Supplement Label Database. Content is written and reviewed by licensed HelloPharmacist pharmacists — see our data sources and editorial standards.
Cefaclor Is Linked to Lower Levels of 7 Nutrients
Natural Medicines records Cefaclor as a medicine that can lower these. This is not an interaction with Thiamine — 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 Cefaclor nutrient depletion report ›
Thiamine is itself a nutrient we track — see which medications may deplete THIAMINE.
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 Thiamine and Cefaclor Together: Common Questions
Is it safe to take Thiamine with Cefaclor?
Do Thiamine and Cefaclor have any of the same side effects?
Should I take Thiamine and Cefaclor at the same time of day?
Can Cefaclor lower my Thiamine levels?
Are Thiamine and Cefaclor used for the same thing?
How was the Thiamine and Cefaclor combination checked?
Does Thiamine interact with any other medications?
Does Cefaclor interact with any supplements?
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.