Major interaction on record — check this product against your medications before combining. Check your meds →
Dietary supplement

High Potency B-1 500 mg Ingredients & Drug Interactions

by Source Naturals

High Potency B-1 500 mg label
See full label image
Tablet Or Pill Category: Single Vitamin And Mineral
Most serious interaction: Major
Clinical methodology reviewed by · Updated Sep 16, 2026 · Label data from the NIH DSLD
What is this page for?

First and foremost: checking High Potency B-1 500 mg against your medications. The heart of this page is the interaction checker and the full interaction report — how this product’s ingredients may interact with prescription and over-the-counter medicines you may be taking.

Around that, we add a pharmacist’s high-level view of the product as a whole — what’s inside, the evidence for its stated use, how transparent the label is, and what safety data exists — so you can see the full picture in one place. It’s educational information from our licensed clinical databases and the clinical staff at HelloPharmacist — not medical advice — and we don’t sell or endorse products. Our editorial policy

The interaction bottom line Most serious interaction: Major

High Potency B-1 500 mg is a dietary supplement by Source Naturals with 2 active ingredients. Its ingredients are commonly taken for preventing or treating thiamine deficiency, beriberi, wernicke-korsakoff syndrome (alcohol-related).Based on those ingredients, 298 medications have a known interaction with it, the most serious rated major. The ingredients most likely to interact are Magnesium Complex, Thiamine. Use the checker below to test your specific medication, or read the full HelloPharmacist Interaction Report.

Jump to a section

Check Your Meds Against High Potency B-1 500 mg by Source Naturals

Ask about any prescription or over-the-counter medication and we check it for interactions with High Potency B-1 500 mg by Source Naturals — and tell you which ingredient is responsible.

Pharmacist-reviewed data Checks every ingredient Answer in seconds
Prefer a human? Send your question to our licensed pharmacists — free, answered by email within 24 hours.

HelloPharmacist Scorecard of High Potency B-1 500 mg by Source Naturals

Our pharmacy team’s full take, with four database checks built into the cards below — a summary of what is known, not a grade of the product itself.

From our pharmacy team — supplement deep dive

Generated from HelloPharmacist’s pharmacist-curated databases and editorial rules · Last generated Aug 6, 2026

What’s inside

Full disclosure
Ingredient Transparency · database check
Full

Every active ingredient lists its own amount on the label.

Why this rating?
  • The label discloses an exact amount for 2 of its 2 active ingredients.
  • No proprietary blends here — you can verify the dose of every single component.

This product contains 2 active ingredients: thiamine (vitamin B-1) at 500 mg, and a magnesium complex. Thiamine is a B vitamin your body needs for energy production and nerve function.

Magnesium is a mineral involved in muscle and nerve function, energy metabolism, and bone health. The tablet also contains inactive ingredients — stearic acid, modified cellulose gum, acacia gum, hydroxypropyl cellulose, magnesium stearate, and silica — which are binders, thickeners, and anti-caking agents that help hold the tablet together.

Does it work?

Strong evidence
Evidence for Intended Use · database check
By FDA rules, dietary supplements can’t claim to treat, cure, or prevent disease — so labels speak in careful marketing language. We discern each product’s intended use from its name, label claims, and label statements, then grade the clinical evidence for that use. How these ratings are computed
Strong

Clinical evidence supports at least one of this product's ingredients for its stated purpose.

Why this rating?
  • The label markets this product for: nerve health and energy production.
  • We looked for evidence on: Cognitive function, Fatigue, Muscle cramps, Anxiety, Thiamine deficiency, Beriberi — and 2 related terms.
  • The strongest evidence on file: Thiamine is rated "Effective" for Thiamine deficiency (Natural Medicines).
  • Also on file: Thiamine is rated "Effective" for Wernicke-Korsakoff syndrome (WKS).
  • Also on file: Magnesium is rated "Possibly Ineffective" for Muscle cramps.

Thiamine is effective for treating thiamine deficiency and Wernicke-Korsakoff syndrome (a serious brain condition from severe thiamine lack). It's possibly effective for period pain (dysmenorrhea) and possibly ineffective for mosquito repellent and heart failure.

Magnesium is effective for indigestion (dyspepsia), constipation, and low magnesium levels in the blood (hypomagnesemia), and it's also effective for preventing pre-eclampsia in pregnancy under medical supervision. If you're taking this for a specific health goal, check with your doctor or pharmacist about whether the evidence supports its use for your situation.

The evidence, ingredient by ingredient Thiamine Magnesium

How safe is it?

Well-documented data
Safety Information · database check
Well characterized

Adverse-effect, pregnancy, and general safety data are on file for most of these ingredients.

Why this rating?
  • We hold adverse-effect (side-effect) data for 2 of the 2 matched ingredients.
  • Pregnancy & breastfeeding safety ratings cover 2 of 2.
  • General safety write-ups exist for 2 of 2.
  • Remember: this measures how much safety information exists. Thin data is not the same as being safe.

Thiamine is generally very safe by mouth at normal amounts. Rarely, it might cause skin reactions or other allergic reactions.

Magnesium is generally well tolerated, but oral doses can cause diarrhea, nausea, vomiting, and gastrointestinal upset. In very rare cases at high doses, magnesium can cause a bezoar (an indigestible lump in the stomach).

Both ingredients are needed in pregnancy and breastfeeding, but the facts advise using supplements only as directed by your doctor — do not self-dose beyond recommended amounts without guidance.

Side effects, ingredient by ingredient Thiamine Magnesium

Meds to double-check

Major interaction found
Known Interaction Concern · database check
Major identified

At least one ingredient has a documented Major-severity interaction. Check your medications for a personalized result.

Why this rating?
  • 2 of the 2 matched ingredients can interact with medications — Thiamine, Magnesium.
  • The most serious interaction on file is rated Major.
  • Some involve high-stakes drug classes: anticoagulant / antiplatelet drugs; diabetes medications; heart-rhythm medications; Parkinson's medications.
  • For scale: 298 individual medications appear in the full list. A big number alone doesn't make a product dangerous — what matters is whether YOUR medication is on it, so run yours through the interaction checker on this page.

Before you start this product, check with your doctor or pharmacist if you take levodopa/carbidopa (a Major interaction). You should also double-check if you use skeletal muscle relaxants, potassium-sparing diuretics, calcium channel blockers, antacids or acid-reducing medications, sulfonylureas (diabetes drugs), quinolone antibiotics, or bisphosphonates — all have Moderate interactions with magnesium.

If you take trimethoprim (an antibiotic), that's a Minor interaction with thiamine, but still worth mentioning.

Check your own medication Run your meds through the checker above

The bottom line

Scorecard at a glanceFully disclosed formula with clinical evidence supporting its stated purpose. Major medication interactions have been identified, and safety information is well characterized.

This B-1 and magnesium supplement works well for thiamine deficiency and certain magnesium-related conditions, but the magnesium content means you'll want to clear it with your doctor or pharmacist first if you take any Parkinson's medications, muscle relaxants, water pills, blood pressure drugs, antibiotics, diabetes medications, or osteoporosis drugs. If you're pregnant or breastfeeding, talk it over with your healthcare provider to confirm the dose is right for you.

Educational only — not medical advice; always confirm with your pharmacist. Our editorial policy · How we use AI

Assessment coverage: 2 of 2 active ingredients matched to our full ingredient reviews (monographs). Based on the product label dated Feb 25, 2019.

This Scorecard evaluates available label information, ingredient evidence, and known medication-safety considerations. It does not independently verify product identity, purity, potency, contamination, or manufacturing quality. How these ratings are computed

At a glance

General information

Key facts about High Potency B-1 500 mg, straight from the product label.

Brand Source Naturals
Barcode (UPC) 021078008873
Net contents 50 Tablet(s)
Market status On market
Date entered into DSLD Feb 25, 2019
DSLD ID 185219
Product type Single Vitamin And Mineral
Supplement form Tablet Or Pill
Dietary claims / uses Nutrient, All Other, Structure/Function
Intended target group(s) Vegetarian, Adult (18 - 50 Years), Gluten Free, Dairy Free, Sugar Free
From the label
Everything in this section is reproduced from the manufacturer’s own product label — it’s the label speaking, not HelloPharmacist. We show it so you can see exactly what the maker states; we don’t verify or endorse those statements.

Supplement Facts

The label details for High Potency B-1 500 mg by Source Naturals, sourced from the NIH Dietary Supplement Label Database.

Supplement Facts

Daily Value (DV) Target Group(s):
Adults and children 4 or more years of age
Minimum serving Sizes:
1 Tablet(s)
Maximum serving Sizes:
1 Tablet(s)
UPC/BARCODE
021078008873
IngredientAmount% DV
Thiamine500 mg33333%
Magnesium Complex100 mg25%

Other ingredients: Stearic Acid, modified Cellulose Gum, Acacia Gum, Hydroxypropyl Cellulose, Magnesium Stearate, Silica

Tap any ingredient to jump to its full detail below.

Label statements
These statements are the manufacturer’s wording, reproduced from the product label — the label is saying it, not HelloPharmacist. We don’t verify or endorse them.
FDA Statement of Identity

Dietary Supplement

Formula

High Potency B-1

B-1 is intimately involved in many aspects of nerve health and function. Once in the body, B-1 is activated to a coenzyme form necessary for energy production and the formation of acetylcholine, a major neurotransmitter. Magnesium plays a role in neuromuscular transmission and activity, and supports muscle relaxation. Excessive alcohol intake may increase the need for B-1, and B-1 may be missing from some diets of highly processed “junk food”.

Suggested/Recommended/Usage/Directions

Suggested Use: 1 tablet daily.

Precautions

Note: If you are pregnant, may become pregnant, or breastfeeding, consult your health care professional before using this product.

Do not use if either tamper-evident seal is broken or missing.

Keep out of the reach of children.

Storage

Store in a cool, dry place.

Formulation

Suitable for vegetarians.

Contains no yeast, dairy, egg, gluten, soy or wheat. Contains no sugar, starch, preservatives, or artificial color, flavor or fragrance.

FDA Disclaimer Statement

These statements have not been evaluated by the Food and Drug Administration. This product is not intended to diagnose, treat, cure or prevent any disease.

General

SN0887 REV F184-A

Is this label outdated? Report a formula or label change and our pharmacy team will review it.

See for yourself

High Potency B-1 500 mg by Source Naturals label

The label scan from the NIH Dietary Supplement Label Database. Tap to enlarge.

High Potency B-1 500 mg label

Label images are published by the NIH Dietary Supplement Label Database for the version of this product on file. Always read your actual product label.

View the full label (PDF)
What’s inside

The Ingredients in High Potency B-1 500 mg by Source Naturals

These are the 2 active ingredients this product is made of. Select any to open its full monograph.

Serving size1 Tablet(s) Dosage formTablet Or Pill Amounts shown are per serving.

Most supplement products combine several ingredients, and a medication can interact with the product through any one of them. Each ingredient below shows whether it has known drug interactions.

Thiamine

Interacts with
3 drugs
500 mg per serving Form: Vitamin B1

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 eno...

Thiamine monograph & interactions

Magnesium Complex

Interacts with
295 drugs
100 mg per serving Form: Magnesium Citrate, Magnesium Malate, Magnesium Oxide, Magnesium Succinic Acid

Magnesium is an essential mineral your body needs for muscles, nerves, blood pressure, and many other functions, and supplements are useful for preven...

Magnesium Complex monograph & interactions

Other (inactive) ingredients: Stearic Acid, Modified Cellulose Gum, Acacia Gum, Hydroxypropyl Cellulose, Magnesium Stearate, Silica. These complete the product’s ingredient list but are not active constituents.

Interaction report

High Potency B-1 500 mg by Source Naturals Drug Interactions

Want to check YOUR meds against High Potency B-1 500 mg?

Ask about interactions with your drugs in plain English — “Can I take it with lisinopril?” — and we find you the answer in seconds, ingredient by ingredient.

 Go to the checker
298Drugs
6 Major 175 Moderate 117 Minor

Ingredients driving the most interactions

Magnesium Complex 295
Thiamine 3

Individual Drug Interactions

The ingredients in High Potency B-1 500 mg interact with 298 drugs. Click any drug to see the details.

2 of the 2 ingredients in High Potency B-1 500 mg interact with drugs. Each result below shows which ingredient is responsible. Magnesium Complex Thiamine

Each ingredient & the kinds of drugs it affects

For each ingredient in High Potency B-1 500 mg with known interactions, here are the types of medications they can affect. Open any type for the detail — or search your exact drug in the checker above.

Magnesium Complex15 drug types · 295 drugs

Levodopa/Carbidopa (Sinemet)

Magnesium can reduce the bioavailability of levodopa/carbidopa.
Clinical research in healthy volunteers shows that taking magnesium oxide 1000 mg with levodopa 100 mg/carbidopa 10 mg reduces the area under the curve (AUC) of levodopa by 35% and of carbidopa by 81%. In vitro and animal research shows that magnesium produces an alkaline environment in the digestive tract, which might lead to degradation and reduced bioavailability of levodopa/carbidopa.

Likelihood Probable Evidence B
Aminoglycoside Antibiotics

Concomitant use of aminoglycoside antibiotics and magnesium can increase the risk for neuromuscular weakness.
Both aminoglycosides and magnesium reduce presynaptic acetylcholine release, which can lead to neuromuscular blockade and possible paralysis. This is most likely to occur with high doses of magnesium given intravenously.

Likelihood Possible Evidence D
Antacids

Use of acid reducers may reduce the laxative effect of magnesium oxide.
A retrospective analysis shows that, in the presence of H2 receptor antagonists (H2RAs) or proton pump inhibitors (PPIs), a higher dose of magnesium oxide is needed for a laxative effect. This may also occur with antacids. Under acidic conditions, magnesium oxide is converted to magnesium chloride and then to magnesium bicarbonate, which has an osmotic laxative effect. By reducing acidity, antacids may reduce the conversion of magnesium oxide to the active bicarbonate salt.

Likelihood Possible Evidence D
Bictegravir/Emtricitabine/Tenofovir Alafenamide (Biktarvy)

Magnesium might decrease levels of bictegravir/emtricitabine/tenofovir alafenamide by reducing its absorption.
Advise patients that bictegravir/emtricitabine/tenofovir alafenamide should be taken at least 2 hours before or 6 hours after magnesium containing products.

Likelihood Probable Evidence D
Bisphosphonates

Magnesium can decrease absorption of bisphosphonates.
Cations, including magnesium, can decrease bisphosphonate absorption. Advise patients to separate doses of magnesium and these drugs by at least 2 hours.

Likelihood Probable Evidence B
Calcium Channel Blockers

Magnesium can have additive effects with calcium channel blockers, although evidence is conflicting.
Magnesium inhibits calcium entry into smooth muscle cells and may therefore have additive effects with calcium channel blockers. Severe hypotension and neuromuscular blockades may occur when nifedipine is used with intravenous magnesium, although some contradictory evidence suggests that concurrent use of magnesium with nifedipine does not increase the risk of neuromuscular weakness. High doses of magnesium could theoretically have additive effects with other calcium channel blockers.

Likelihood Possible Evidence D
Digoxin

Magnesium salts may reduce absorption of digoxin.
Clinical evidence suggests that treatment with oral magnesium hydroxide or magnesium trisilicate reduces absorption of digoxin from the intestines. This may reduce the blood levels of digoxin and decrease its therapeutic effects.

Likelihood Possible Evidence B
Potassium-Sparing Diuretics

Potassium-sparing diuretics decrease excretion of magnesium, possibly increasing magnesium levels.
Potassium-sparing diuretics also have magnesium-sparing properties, which can counteract the magnesium losses associated with loop and thiazide diuretics. Theoretically, increased magnesium levels could result from concomitant use of potassium-sparing diuretics and magnesium supplements.

Likelihood Probable Evidence D
Quinolone Antibiotics

Magnesium decreases absorption of quinolones.
Magnesium can form insoluble complexes with quinolones and decrease their absorption. Advise patients to take these drugs at least 2 hours before, or 4 to 6 hours after, magnesium supplements.

Likelihood Probable Evidence D
Skeletal Muscle Relaxants

Parenteral magnesium alters the pharmacokinetics of skeletal muscle relaxants, increasing their effects and accelerating the onset of effect.
Parenteral magnesium shortens the time to onset of skeletal muscle relaxants by about 1 minute and prolongs the duration of action by about 2 minutes. Magnesium potentiates the effects of skeletal muscle relaxants by decreasing calcium-mediated release of acetylcholine from presynaptic nerve terminals, reducing postsynaptic sensitivity to acetylcholine, and having a direct effect on the membrane potential of myocytes. Magnesium also has vasodilatory actions and increases cardiac output, allowing a greater amount of muscle relaxant to reach the motor end plate. A clinical study found that low-dose rocuronium (0.45 mg/kg), when given after administration of magnesium 30 mg/kg over 10 minutes, has an accelerated onset of effect, which matches the onset of effect seen with a full-dose rocuronium regimen (0.6 mg/kg). In another clinical study, onset times for rocuronium doses of 0.3, 0.6, and 1.2 mg/kg were 86, 76, and 50 seconds, respectively, when given alone, but were reduced to 66, 44, and 38 seconds, respectively, when the doses were given after a 15-minute infusion of magnesium sulfate 60 mg/kg. Giving intraoperative intravenous magnesium sulfate, 50 mg/kg loading dose followed by 15 mg/kg/hour, reduces the onset time of rocuronium, enhances its clinical effects, reduces the dose of intraoperative opiates, and prolongs the spontaneous recovery time. It does not affect the activity of subsequently administered neostigmine.

Likelihood Probable Evidence A
Sulfonylureas

Magnesium increases the systemic absorption of sulfonylureas, increasing their effects and side effects.
Clinical research shows that administration of magnesium hydroxide with glyburide increases glyburide absorption, increases maximal insulin response by 35-fold, and increases the risk of hypoglycemia, when compared with glyburide alone. A similar interaction occurs between magnesium hydroxide and glipizide. The mechanism of this effect appears to be related to the elevation of gastrointestinal pH by magnesium-based antacids, increasing solubility and enhancing absorption of sulfonylureas.

Likelihood Probable Evidence B
Tetracycline Antibiotics

Magnesium decreases absorption of tetracyclines.
Magnesium can form insoluble complexes with tetracyclines in the gut and decrease their absorption and antibacterial activity. Advise patients to take these drugs 1 hour before or 2 hours after magnesium supplements.

Likelihood Probable Evidence D
Anticoagulant/Antiplatelet Drugs

Theoretically, magnesium may have antiplatelet effects, but the evidence is conflicting.
In vitro evidence shows that magnesium sulfate inhibits platelet aggregation, even at low concentrations. Some preliminary clinical evidence shows that infusion of magnesium sulfate increases bleeding time by 48% and reduces platelet activity. However, other clinical research shows that magnesium does not affect platelet aggregation, although inhibition of platelet-dependent thrombosis can occur.

Likelihood Unlikely Evidence B
Gabapentin (Neurontin)

Gabapentin absorption can be decreased by magnesium.
Clinical research shows that giving magnesium oxide orally along with gabapentin decreases the maximum plasma concentration of gabapentin by 33%, time to maximum concentration by 36%, and area under the curve by 43%. Advise patients to take gabapentin at least 2 hours before, or 4 to 6 hours after, magnesium supplements.

Likelihood Unlikely Evidence B
Sevelamer (Renagel, Renvela)

Sevelamer may increase serum magnesium levels.
In patients on hemodialysis, sevelamer use was associated with a 0.28 mg/dL increase in serum magnesium. The mechanism of this interaction remains unclear.

Likelihood Possible Evidence B
Magnesium Complex full monograph & interactions

Thiamine1 drug type · 3 drugs

Trimethoprim (Proloprim)

Trimethoprim might increase blood levels of thiamine.
In vitro, animal, and clinical research suggest that trimethoprim inhibits intestinal thiamine transporter ThTR-2, hepatic transporter OCT1, and renal transporters OCT2, MATE1, and MATE2, resulting in paradoxically increased thiamine plasma concentrations.

Likelihood Probable Evidence B
Thiamine full monograph & interactions
The maker

Brand information

Manufacturer and brand details for High Potency B-1 500 mg, from the product label.

Source Naturals

Name
Source Naturals, Inc.
Street Address
P. O. Box 2118
City
Santa Cruz
State
CA
ZipCode
95062
Web Address
www.sourcenaturals.com
Pharmacist Counseling Corner

High Potency B-1 500 mg by Source Naturals: Common Questions

Does High Potency B-1 500 mg by Source Naturals interact with any medications?
Yes. Based on its ingredients, High Potency B-1 500 mg has a known interaction with 298 medications, including 6 rated major. Use the checker to see how it interacts with a specific drug.
How can one product interact with so many drugs?
High Potency B-1 500 mg contains 2 active ingredients, and an interaction can come from any of them. We check every ingredient, combine the results into one list per medication, and show which ingredient and mechanism is responsible.
Where does this information come from?
The product label data comes from the NIH Dietary Supplement Label Database (DSLD); the interaction data is built on the Natural Medicines database and reviewed by HelloPharmacist pharmacists.
Is thiamine the same as vitamin B-1?
Yes — thiamine is another name for vitamin B-1. It's a B vitamin your body uses to turn food into energy and keep your nerves working properly.
Can I take this while I'm pregnant?
Both thiamine and magnesium are nutrients your body needs in pregnancy, but the facts advise using supplement doses only as directed by your doctor. Don't self-dose beyond recommended amounts — talk with your provider about the right amount for you.
What's the most common side effect of magnesium?
Diarrhea is the most common side effect when you take magnesium by mouth. Nausea, vomiting, and general stomach upset can happen too, especially at higher doses.
Will this supplement help with my low magnesium?
Yes — magnesium is effective for treating low magnesium levels in the blood. Your doctor can confirm whether you're low and whether this supplement is the right choice for you.
Is this safe for someone with constipation?
Magnesium is actually effective for constipation, so this product could help. But start with the recommended dose and watch for diarrhea, since that's the trade-off — too much can cause loose stools.

Written and reviewed by the HelloPharmacist editorial staff. Our editorial policy

Not sure if High Potency B-1 500 mg is safe with your meds?

Our pharmacists answer your medication & supplement questions — free.

Ask a pharmacist

Label information is sourced from the NIH Dietary Supplement Label Database and reflects the product version on file; always read your actual product label. This page is for education only and is not a substitute for professional medical advice. Confirm with your pharmacist or doctor before combining supplements and medications.

High Potency B-1 500 mg label
Go deeper

The Full Monographs Behind High Potency B-1 500 mg’s Ingredients

Every ingredient we hold a full HelloPharmacist monograph for — uses, evidence, safety, and the complete interaction list.

Herb & supplement monograph

Thiamine

Interacts with 3 drugs

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 clear...

Read the full Thiamine monograph → Herb & supplement monograph

Magnesium

Interacts with 295 drugs

Magnesium is an essential mineral your body needs for muscles, nerves, blood pressure, and many other functions, and supplements are useful for preventing or correcting deficiency. Some othe...

Read the full Magnesium monograph →
Sources

Sources & How We Checked

High Potency B-1 500 mg's label data comes from the NIH Dietary Supplement Label Database; the ingredient interaction data is from the Natural Medicines database, reviewed by our pharmacists.

Content is written and reviewed by licensed HelloPharmacist pharmacists. See our data sources and editorial standards for how this information is built and checked.

The 89 references behind this product’s interaction data

Every citation that drives the interaction findings for this product’s ingredients, from the evidence-graded Natural Medicines (TRC Healthcare) database. Open an ingredient to browse its citations — links open the study on PubMed or the publisher’s site.

Thiamine 7 references
  1. McEvoy GK, ed. AHFS Drug Information. Bethesda, MD: American Society of Health-System Pharmacists, 1998.
  2. 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
  3. 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
  4. 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
  5. 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
  6. Thiamine hydrochloride injection package insert. Lake Zurich, IL: Fresenius Kabi, LLC; September 2019.
  7. 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.

See these in context on the Thiamine monograph →

Magnesium 82 references
  1. Rodin SM, Johnson BF. Pharmacokinetic interactions with digoxin. Clin Pharmacokinet 1988;15:227-44.
  2. Covington TR, et al. Handbook of Nonprescription Drugs. 11th ed. Washington, DC: American Pharmaceutical Association, 1996.
  3. Dahle LO, Berg G, Hammar M, et al. The effect of oral magnesium substitution on pregnancy-induced leg cramps. Am J Obstet Gynecol 1995;173:175-80. PubMed
  4. Hansten PD, Horn JR. Drug Interactions Analysis and Management. Vancouver, WA: Applied Therapeutics Inc., 1997 and updates.
  5. Peikert A, Wilimzig C, Kohne-Volland R. Prophylaxis of migraine with oral magnesium: results from a prospective, multi-center, placebo-controlled and double-blind randomized study. Cephalalgia 1996;16:257-63. PubMed
  6. Food and Nutrition Board, Institute of Medicine. Dietary Reference Intakes for Calcium, Phosphorus, Magnesium, Vitamin D, and Fluoride. Washington, DC: National Academy Press, 1999. Available at: http://books.nap.edu/books/0309063507/html/index.html.
  7. Birrer RB, Shallash AJ, Totten V. Hypermagnesemia-induced fatality following epsom salt gargles. J Emerg Med 2002;22:185-8. PubMed
  8. Ryan MP. Diuretics and potassium/magnesium depletion. Directions for treatment. Am J Med 1987;82:38-47.. PubMed
  9. Hollifield JW. Magnesium depletion, diuretics, and arrhythmias. Am J Med 1987;82:30-7.. PubMed
  10. Heidenreich O. Mode of action of conventional and potassium-sparing diuretics--aspects with relevance to Mg-sparing effects. Magnesium 1984;3:248-56..
  11. Pfaffenrath V, Wessely P, Meyer C, et al. Magnesium in the prophylaxis of migraine--a double-blind placebo-controlled study. Cephalalgia 1996;16:436-40.. PubMed
  12. Wang F, Van Den Eeden SK, Ackerson LM, et al. Oral magnesium oxide prophylaxis of frequent migrainous headache in children: a randomized, double-blind, placebo-controlled trial. Headache 2003;43:601-10.. PubMed
  13. Sompolinsky D, Samra Z. Influence of magnesium and manganese on some biological and physical properties of tetracycline. J Bacteriol 1972;110:468-76.. PubMed
  14. Jeyabalan A, Caritis SN. Pharmacologic inhibition of preterm labor. Clin Obstet Gynecol 2002;45:99-113. PubMed
  15. Mittendorf R, Dambrosia J, Pryde PG, et al. Association between the use of antenatal magnesium sulfate in preterm labor and adverse health outcomes in infants. Am J Obstet Gynecol 2002;186:1111-8.. PubMed
  16. Witlin AG, Sibai BM. Magnesium sulfate therapy in preeclampsia and eclampsia. Obstet Gynecol 1998;92:883-9.. DOI
  17. Crowther CA, Hiller JE, Doyle LW. Magnesium sulphate for preventing preterm birth in threatened preterm labour. Cochrane Database Syst Rev 2002;4:CD001060. . PubMed
  18. Davey MJ, Teubner D. A randomized controlled trial of magnesium sulfate, in addition to usual care, for rate control in atrial fibrillation. Ann Emerg Med 2005;45:347-53.. PubMed
  19. L'Hommedieu CS, Nicholas D, Armes DA, et al. Potentiation of magnesium sulfate--induced neuromuscular weakness by gentamicin, tobramycin, and amikacin. J Pediatr 1983;102:629-31..
  20. Dunn CJ, Goa KL. Risedronate: a review of its pharmacological properties and clinical use in resorptive bone disease. Drugs 2001;61:685-712..
  21. Kass L, Weekes J, Carpenter L. Effect of magnesium supplementation on blood pressure: a meta-analysis. Eur J Clin Nutr 2012;66:411-8. PubMed
  22. Koontz SL, Friedman SA, Schwartz ML. Symptomatic hypocalcemia after tocolytic therapy with magnesium sulfate and nifedipine. Am J Obstet Gynecol. 2004;190(6):1773-6. PubMed
  23. Snyder SW, Cardwell MS. Neuromuscular blockade with magnesium sulfate and nifedipine. Am J Obstet Gynecol. 1989;161(1):35-6. PubMed
  24. Waisman GD, Mayorga LM, Cámera MI, et al. Magnesium plus nifedipine: potentiation of hypotensive effect in preeclampsia? Am J Obstet Gynecol. 1988;159(2):308-9. PubMed
  25. Brown DD, Juhl RP. Decreased bioavailability of digoxin due to antacids and kaolin-pectin. N Engl J Med. 1976;295(19):1034-7. PubMed
  26. Allen MD, Greenblatt DJ, Harmatz JS, et al. Effect of magnesium--aluminum hydroxide and kaolin--pectin on absorption of digoxin from tablets and capsules. J Clin Pharmacol. 1981;21(1):26-30. PubMed
  27. Ravn HB, Vissinger H, Kristensen SD, et al. Magnesium inhibits platelet activity--an in vitro study. Thromb Haemost. 1996;76(1):88-93. DOI
  28. Ravn HB, Kristensen SD, Vissinger H, et al. Magnesium inhibits human platelets. Blood Coagul Fibrinolysis. 1996;7(2):241-4. PubMed
  29. Ravn HB, Vissinger H, Kristensen SD, et al. Magnesium inhibits platelet activity--an infusion study in healthy volunteers. Thromb Haemost. 1996;75(6):939-44. DOI
  30. Neuvonen PJ, Kivistö KT. The effects of magnesium hydroxide on the absorption and efficacy of two glibenclamide preparations. Br J Clin Pharmacol. 1991;32(2):215-20. PubMed
  31. Kivistö KT, Neuvonen PJ. Enhancement of absorption and effect of glipizide by magnesium hydroxide. Clin Pharmacol Ther. 1991;49(1):39-43. PubMed
  32. Neuvonen PJ, Kivistö KT. Enhancement of drug absorption by antacids. An unrecognised drug interaction. Clin Pharmacokinet. 1994;27(2):120-8. PubMed
  33. Shechter, M., Merz, C. N., Paul-Labrador, M., Meisel, S. R., Rude, R. K., Molloy, M. D., Dwyer, J. H., Shah, P. K., and Kaul, S. Beneficial antithrombotic effects of the association of pharmacological oral magnesium therapy with aspirin in coronary heart
  34. Ganzevoort, J. W., Hoogerwaard, E. M., and van der Post, J. A. [Hypocalcemic delirium due to magnesium sulphate therapy in a pregnant woman with pre-eclampsia]. Ned.Tijdschr.Geneeskd. 8-3-2002;146(31):1453-1456.
  35. Horner, S. M. Efficacy of intravenous magnesium in acute myocardial infarction in reducing arrhythmias and mortality. Meta-analysis of magnesium in acute myocardial infarction. Circulation 1992;86(3):774-779. PubMed
  36. Azria, E., Tsatsaris, V., Goffinet, F., Kayem, G., Mignon, A., and Cabrol, D. [Magnesium sulfate in obstetrics: current data]. J Gynecol.Obstet.Biol.Reprod.(Paris) 2004;33(6 Pt 1):510-517.
  37. Magee, L. A., Miremadi, S., Li, J., Cheng, C., Ensom, M. H., Carleton, B., Cote, A. M., and von Dadelszen, P. Therapy with both magnesium sulfate and nifedipine does not increase the risk of serious magnesium-related maternal side effects in women with p
  38. Henyan, N. N., Gillespie, E. L., White, C. M., Kluger, J., and Coleman, C. I. Impact of intravenous magnesium on post-cardiothoracic surgery atrial fibrillation and length of hospital stay: a meta-analysis. Ann.Thorac.Surg. 2005;80(6):2402-2406. PubMed
  39. Li, J., Zhang, Q., Zhang, M., and Egger, M. Intravenous magnesium for acute myocardial infarction. Cochrane.Database.Syst.Rev. 2007;(2):CD002755. PubMed
  40. Doyle, L. W., Crowther, C. A., Middleton, P., Marret, S., and Rouse, D. Magnesium sulphate for women at risk of preterm birth for neuroprotection of the fetus. Cochrane.Database.Syst.Rev. 2009;(1):CD004661. PubMed
  41. Han, S., Crowther, C. A., and Moore, V. Magnesium maintenance therapy for preventing preterm birth after threatened preterm labour. Cochrane.Database.Syst.Rev. 2010;(7):CD000940. PubMed
  42. Duley, L., Gulmezoglu, A. M., Henderson-Smart, D. J., and Chou, D. Magnesium sulphate and other anticonvulsants for women with pre-eclampsia. Cochrane.Database.Syst.Rev. 2010;(11):CD000025. PubMed
  43. Conde-Agudelo, A., Romero, R., and Kusanovic, J. P. Nifedipine in the management of preterm labor: a systematic review and metaanalysis. Am J Obstet.Gynecol. 2011;204(2):134-20. PubMed
  44. Wong, G. K., Boet, R., Poon, W. S., Chan, M. T., Gin, T., Ng, S. C., and Zee, B. C. Intravenous magnesium sulphate for aneurysmal subarachnoid hemorrhage: an updated systemic review and meta-analysis. Crit Care 2011;15(1):R52. PubMed
  45. Magee, L., Sawchuck, D., Synnes, A., and von, Dadelszen P. SOGC Clinical Practice Guideline. Magnesium sulphate for fetal neuroprotection. J Obstet.Gynaecol.Can. 2011;33(5):516-529.
  46. Doyle, L. W. Antenatal magnesium sulfate and neuroprotection. Curr Opin Pediatr 2012;24(2):154-159. PubMed
  47. McDonald, S. D., Lutsiv, O., Dzaja, N., and Duley, L. A systematic review of maternal and infant outcomes following magnesium sulfate for pre-eclampsia/eclampsia in real-world use. Int J Gynaecol.Obstet. 2012;118(2):90-96. PubMed
  48. Gordon, M., Naidoo, K., Akobeng, A. K., and Thomas, A. G. Osmotic and stimulant laxatives for the management of childhood constipation. Cochrane.Database.Syst.Rev. 2012;7:CD009118. PubMed
  49. Dodd, J. M., Crowther, C. A., and Middleton, P. Oral betamimetics for maintenance therapy after threatened preterm labour. Cochrane.Database.Syst.Rev. 2012;12:CD003927. PubMed
  50. Wu, X., Wang, C., Zhu, J., Zhang, C., Zhang, Y., and Gao, Y. Meta-analysis of randomized controlled trials on magnesium in addition to beta-blocker for prevention of postoperative atrial arrhythmias after coronary artery bypass grafting. BMC.Cardiovasc.D PubMed
  51. Thorp, J. M., Jr., Katz, V. L., Campbell, D., and Cefalo, R. C. Hypersensitivity to magnesium sulfate. Am.J.Obstet.Gynecol. 1989;161(4):889-890. PubMed
  52. Duley L and Gulmezoglu AM. Magnesium sulphate versus lytic cocktail for eclampsia. Cochrane Database of Systematic Reviews 2000;(3) PubMed
  53. Gibbins KJ, Browning KR, Lopes VV, Anderson BL, Rouse DJ. Evaluation of the clinical use of magnesium sulfate for cerebral palsy prevention. Obstet Gynecol 2013;121(2 Pt 1):235-40. PubMed
  54. Ji D. Oral magnesium sulfate causes perforation during bowel preparation for fiberoptic colonoscopy in patients with colorectal cancer. J Emerg Med 2012;43(4):716-7. PubMed
  55. Yagi T, Naito T, Mino Y, Umemura K, Kawakami J. Impact of concomitant antacid administration on gabapentin plasma exposure and oral bioavailability in healthy adult subjects. Drug Metab Pharmacokinet 2012;27(2):248-54. PubMed
  56. Yamasaki M, Funakoshi S, Matsuda S, Imazu T, Takeda Y, Murakami T, Maeda Y. Interaction of magnesium oxide with gastric acid secretion inhibitors in clinical pharmacotherapy. Eur J Clin Pharmacol 2014;70(8):921-4. PubMed
  57. Choi ES, Jeong WJ, Ahn SH, Oh AY, Jeon YT, Do SH. Magnesium sulfate accelerates the onset of low-dose rocuronium in patients undergoing laryngeal microsurgery. J Clin Anesth. 2017 Feb;36:102-106. PubMed
  58. Ikee R, Toyoyama T, Endo T, Tsunoda M, Hashimoto N. Impact of sevelamer hydrochloride on serum magnesium concentrations in hemodialysis patients. Magnes Res. 2016 Apr 1;29(4):184-90. PubMed
  59. Miller ES, Sakowicz A, Leger E. Lange E, Yee LM. The association between receipt of intrapartum magnesium and postpartum hemorrhage. Am J Obstet Gynecol 2018;218(1 Suppl):S165.
  60. Rodríguez-Rubio L, Solis Garcia Del Pozo J, Nava E, Jordán J. Interaction between magnesium sulfate and neuromuscular blockers during the perioperative period. A systematic review and meta-analysis. J Clin Anesth. 2016;34:524-34. PubMed
  61. Brown RS. Magnesium Sulfate: Another Cause of a Solute Diuresis. Am J Kidney Dis. 2017;69(4):550-551. PubMed
  62. Park H, Qin R, Smith TJ, et al. North Central Cancer Treatment Group N10C2 (Alliance): a double-blind placebo-controlled study of magnesium supplements to reduce menopausal hot flashes. Menopause. 2015;22(6):627-32. PubMed
  63. Sakanoue M, Sanada J, Kanekura T. Skin eruption elicited by magnesium oxide (Maglax). J Dermatol. 2016;43(2):221-2.
  64. Iwamuro M, Saito S, Yoshioka M, et al. A Magnesium Oxide Bezoar. Intern Med. 2018;57(21):3087-3091. PubMed
  65. Vilchez G, Dai J, Kumar K, Mundy D, Kontopoulos E, Sokol RJ. Racial/ethnic disparities in magnesium sulfate neuroprotection: a subgroup analysis of a multicenter randomized controlled trial. J Matern Fetal Neonatal Med. 2018;31(17):2304-2311. PubMed
  66. Drug Safety Communication: FDA Recommends Against Prolonged Use of Magnesium Sulfate to Stop Pre-term Labor Due to Bone Changes in Exposed Babies. U.S. Food and Drug Administration (FDA), May 30, 2013. https://www.fda.gov/downloads/Drugs/DrugSafety/UCM353
  67. Committee Opinion: Magnesium Sulfate Use in Obstetrics. The American College of Obstetricians and Gynecologists Committee on Obstetric Practice Society for Maternal-Fetal Medicine, Number 652, January 2016. https://www.acog.org/Clinical-Guidance-and-Publi
  68. Kashihara Y, Terao Y, Yoda K, et al. Effects of magnesium oxide on pharmacokinetics of L-dopa/carbidopa and assessment of pharmacodynamic changes by a model-based simulation. Eur J Clin Pharmacol. 2019;75(3):351-361. PubMed
  69. Shepherd E, Salam RA, Manhas D, et al. Antenatal magnesium sulphate and adverse neonatal outcomes: A systematic review and meta-analysis. PLoS Med. 2019;16(12):e1002988. PubMed
  70. Hong JY, Hong JY, Choi YS, et al. Antenatal magnesium sulfate treatment and risk of necrotizing enterocolitis in preterm infants born at less than 32 weeks of gestation. Sci Rep. 2020;10(1):12826. PubMed
  71. Schuh S, Sweeney J, Rumantir M, et al. Effect of nebulized magnesium vs placebo added to albuterol on hospitalization among children with refractory acute asthma treated in the emergency department: a randomized clinical trial. JAMA. 2020;324(20):2038-20 PubMed
  72. Almeida CED, Carvalho LR, Andrade CVC, Nascimento PD Jr, Barros GAM, Modolo NSP. Effects of magnesium sulphate on the onset time of rocuronium at different doses: a randomized clinical trial. Braz J Anesthesiol. 2021;71(5):482-8. PubMed
  73. Gochi Valdovinos A, Arriaga-Redondo M, Dejuan Bitriá E, Pérez Rodríguez I, Márquez Isidro E, Blanco Bravo D. Prenatal therapy with magnesium sulphate and intestinal obstruction due to meconium in preterm newborns. An Pediatr (Engl Ed). 2022 Feb;96(2):138- PubMed
  74. Iio K, Kondo E, Shibata E, et al. Long-term tocolysis with magnesium sulfate as a risk factor for low bone mass: a case series. J Med Cases. 2022 Feb;13(2):47-50. PubMed
  75. Eiraku K, Uozumi Y, Hieda M, Maruyama T, Nomura H. A senile case of heart failure associated with hypermagnesemia induced by magnesium-containing laxative agent. Geriatr Gerontol Int. 2022;22(10):897-899.
  76. Enayati A, Gin JH, Sajeev JK, et al. Efficacy of intravenous magnesium for the management of non-post operative atrial fibrillation with rapid ventricular response: A systematic review and meta-analysis. J Cardiovasc Electrophysiol 2023;34(5):1286-1295. PubMed
  77. Su YH, Luo DC, Pang Y. Effects of intraoperative Magnesium sulfate infusion on emergency agitation during general anesthesia in patients undergoing radical mastectomy: a randomized controlled study. BMC Anesthesiol 2023;23(1):326. PubMed
  78. Han J, Park HY, Shin HJ, Chung SH, Do SH. Effects of magnesium sulphate on neostigmine-induced recovery from moderate neuromuscular blockade with rocuronium: a randomized controlled trial. Magnes Res 2023;36(2):31-39. PubMed
  79. Lee AT, Cordova JC, Jamplis RP, Pomicter GR. Posterior Reversible Encephalopathy Syndrome and Eclampsia in the Setting of Magnesium Toxicity: A Case Report. A A Pract 2023;17(11):e01726. PubMed
  80. Darmawan D, Rengganis I, Rumende CM, et al. Effectiveness and Safety of Nebulized Magnesium as Last Line Treatment in Adults with Acute Asthma Attack: A Systematic Review and Meta-Analysis. Acta Med Indones 2024;56(1):3-12.
  81. Shepherd ES, Goldsmith S, Doyle LW, et al. Magnesium sulphate for women at risk of preterm birth for neuroprotection of the fetus. Cochrane Database Syst Rev 2024;5(5):CD004661. PubMed
  82. US Food and Drug Administration (FDA). Biktarvy Prescribing Information. October 2024. Available at: https://www.accessdata.fda.gov/drugsatfda_docs/label/2024/210251Orig1s020lbl.pdf. Accessed July 16, 2025.

See these in context on the Magnesium monograph →

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
Supplement interaction checker › Check any supplement or product against your medications Drug–drug interactions › Check two or more of your medications against each other Browse medications A–Z › Every drug we've checked against herbs & supplements NDC & pricing lookup › Find a drug’s NDCs, packaging and costs Ask a pharmacist › Free, personal answer from our licensed team