B1 100 mg Ingredients & Drug Interactions
by Nature Made
What is this page for?
First and foremost: checking B1 100 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
B1 100 mg is a dietary supplement by Nature Made with 2 active ingredients. Its ingredients are commonly taken for bone health and osteoporosis prevention, dietary calcium deficiency, heartburn relief (calcium carbonate antacids).Based on those ingredients, 171 medications have a known interaction with it, the most serious rated major. The ingredients most likely to interact are Calcium, Thiamine. Use the checker below to test your specific medication, or read the full HelloPharmacist Interaction Report.
Check Your Meds Against B1 100 mg by Nature Made
Ask about any prescription or over-the-counter medication and we check it for interactions with B1 100 mg by Nature Made — and tell you which ingredient is responsible.
AI summaries are generated from our interaction database for education only — always confirm with your pharmacist. How we use AI
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HelloPharmacist Scorecard of B1 100 mg by Nature Made
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.
What’s inside
Full disclosure
This tablet contains two active ingredients: calcium and thiamine (vitamin B1). Calcium supports bone health and plays a role in nerve and muscle function.
Thiamine is an essential B vitamin your body needs for energy metabolism and nerve function. The product also contains several inactive ingredients — cellulose gel, maltodextrin, croscarmellose sodium, and magnesium stearate — which are fillers and binders that hold the tablet together.
Does it work?
Strong evidence
Calcium is effective for preventing and treating low blood calcium (hypocalcemia), managing high potassium levels (hyperkalemia), and treating bone loss (osteoporosis); it's also effective for heartburn (dyspepsia) and kidney failure. Thiamine is effective for thiamine deficiency and Wernicke-Korsakoff syndrome (a serious brain condition from thiamine deficiency).
It may help with painful periods (dysmenorrhea), but evidence is limited. For mosquito repellent, thiamine appears ineffective, and evidence for heart failure is also lacking.
How safe is it?
Well-documented data
Calcium is generally well tolerated at recommended doses, though high amounts can cause problems. The most common side effects from taking it by mouth are belching, constipation, diarrhea, bloating, and stomach upset.
Rare concerns include kidney stones and a serious skin condition called calciphylaxis. Some research suggests very high daily calcium intake (over 1500–2000 mg) may be linked to increased prostate cancer risk and possibly heart disease, though these findings are debated.
Thiamine is very safe by mouth in normal amounts; allergic reactions and skin irritation are rare. High-dose injections can rarely cause serious allergic reactions, but oral supplements don't carry that risk.
Meds to double-check
Major interaction found
Before taking this product, check with your doctor or pharmacist if you take any HIV integrase inhibitor (dolutegravir or elvitegravir), the antibiotic ceftriaxone (especially intravenously), the thyroid drug levothyroxine, the heart drugs diltiazem or sotalol, the HIV drug raltegravir, the psoriasis cream calcipotriene, or the antibiotic trimethoprim. Calcium can significantly reduce how well some of these work, while trimethoprim may raise your thiamine levels.
Spacing doses apart or adjusting your regimen may be needed.
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 product is useful if you need calcium for bone health, low blood calcium, or heartburn, or thiamine for a deficiency — but calcium's interactions with HIV drugs, thyroid medication, and certain heart drugs make it essential to run your prescriptions through the checker on this page first. If you take levothyroxine, separate it from this supplement by at least 4 hours.
Talk with your doctor or pharmacist before starting, especially if you're pregnant, breastfeeding, or have a history of kidney stones or prostate cancer.
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 Jan 23, 2023.
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
General information
Key facts about B1 100 mg, straight from the product label.
| Brand | Nature Made |
|---|---|
| Barcode (UPC) | 031604012816 |
| Net contents | 100 Tablet(s) |
| Market status | On market |
| Date entered into DSLD | Jan 23, 2023 |
| DSLD ID | 287362 |
| Product type | Single Vitamin And Mineral |
| Supplement form | Tablet Or Pill |
| Dietary claims / uses | All Other, Structure/Function |
| Intended target group(s) | Adult (18 - 50 Years), Gluten Free |
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 B1 100 mg by Nature Made, sourced from the NIH Dietary Supplement Label Database.
Supplement Facts
| Ingredient | Amount | % DV |
|---|---|---|
| Calcium | 34 mg | 3% |
| Thiamine | 100 mg | 8333% |
Other ingredients: Cellulose Gel, Maltodextrin, Croscarmellose Sodium, Magnesium Stearate
Tap any ingredient to jump to its full detail below.
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.
General Statements
#1 pharmacist recommended vitamin & supplement brand
Based on Pharmacy Times Survey of pharmacists recommending Letter Vitamin Supplements.
Seals/Symbols
USP Verified Dietary Supplement
Formulation
Helps support nervous system function Helps convert food into cellular energy
USP has tested and verified ingredients, potency and manufacturing process. USP sets official standards for dietary supplements. www.uspverified.org
No color added No artificial flavors No preservatives Gluten free
FDA Statement of Identity
Dietary Supplement
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.
Suggested/Recommended/Usage/Directions
Suggested use: Adults, take 1 tablet daily with water and a meal.
Storage
Store tightly closed, in a cool, dry place, out of reach of children.
Precautions
Store tightly closed, in a cool, dry place, out of reach of children.
Do not use if imprinted seal under cap is broken or missing.
Caution: If you are taking medication, including anticonvulsants, consult your physician before use.
Is this label outdated? Report a formula or label change and our pharmacy team will review it.
B1 100 mg by Nature Made label
The label scan from the NIH Dietary Supplement Label Database. Tap to enlarge.
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)The Ingredients in B1 100 mg by Nature Made
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 Servings per container100 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.
Calcium
Interacts with168 drugs
Calcium is an essential mineral your body needs for strong bones, nerve signaling, and muscle function, and supplements can help fill gaps when diet f...
Calcium monograph & interactionsThiamine
Interacts with3 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 eno...
Thiamine monograph & interactionsOther (inactive) ingredients: Cellulose Gel, Maltodextrin, Croscarmellose Sodium, Magnesium Stearate. These complete the product’s ingredient list but are not active constituents.
B1 100 mg by Nature Made Drug Interactions
HelloPharmacist Interaction Report
Nature Made's B1 100 mg contains calcium and thiamine.
Calcium carries the most significant interaction concerns — it can substantially reduce levels of two HIV integrase inhibitors (dolutegravir and elvitegravir), which may compromise their effectiveness. It also poses a Major risk if given intravenously alongside the antibiotic ceftriaxone, which can cause dangerous precipitation in the lungs and kidneys; this is mainly a hospital concern, but worth knowing.
If you take either of those HIV drugs or receive IV ceftriaxone, separate your calcium supplement by several hours (2–6 hours depending on the drug) or avoid it altogether — your doctor will advise.
Read the full breakdown — every affected drug type, severity by severity
Calcium also moderately reduces how well your body absorbs the thyroid drug levothyroxine, the heart drug diltiazem, and the blood-pressure beta-blocker sotalol. It may slightly lower levels of the HIV drug raltegravir, and combining it with the psoriasis cream calcipotriene could raise your blood calcium too high.
Thiamine interacts with only one medication we have data for — the antibiotic trimethoprim — at Minor severity, and the effect is actually an increase in thiamine levels, not a decrease.
Altogether, these interactions span 171 individual medications. To see if any of your prescriptions are affected, run them through the interaction checker below with this product.
Check your own medications below · Editorial policy · How we use AI
Want to check YOUR meds against B1 100 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 checkerIngredients driving the most interactions
Individual Drug Interactions
The ingredients in B1 100 mg interact with 171 drugs. Click any drug to see the details.
2 of the 2 ingredients in B1 100 mg interact with drugs. Each result below shows which ingredient is responsible. Calcium Thiamine
CeftriaxoneRocephin
How Ceftriaxone interacts with B1 100 mg — through 1 ingredient. Tap an ingredient for the detail:
CalciumCeftriaxone (rocephin) Major
Interaction Summary
Co-administration of intravenous calcium and ceftriaxone can result in precipitation of a ceftriaxone-calcium salt in the lungs and kidneys.
Read the full Calcium + Ceftriaxone interactionCobicistat, Elvitegravir, Emtricitabine, Tenofovir Alafenamide FumarateGenvoya
How Cobicistat, Elvitegravir, Emtricitabine, Tenofovir Alafenamide Fumarate interacts with B1 100 mg — through 1 ingredient. Tap an ingredient for the detail:
CalciumElvitegravir (vitekta), Bictegravir/emtricitabine/tenofovir Alafenamide (biktarvy) Major
Interaction Summary
Calcium seems to reduce levels of elvitegravir.
Read the full Calcium + Cobicistat, Elvitegravir, Emtricitabine, Tenofovir Alafenamide Fumarate interactionDolutegravirTivicay
How Dolutegravir interacts with B1 100 mg — through 1 ingredient. Tap an ingredient for the detail:
CalciumDolutegravir (tivicay) Major
Interaction Summary
Calcium seems to reduce levels of dolutegravir.
Read the full Calcium + Dolutegravir interactionDolutegravir, Emtricitabine, Tenofovir AlafenamideDolutegravir, Emtricitabine, Tenofovir Alafenamide
How Dolutegravir, Emtricitabine, Tenofovir Alafenamide interacts with B1 100 mg — through 1 ingredient. Tap an ingredient for the detail:
CalciumDolutegravir (tivicay), Bictegravir/emtricitabine/tenofovir Alafenamide (biktarvy) Major
Interaction Summary
Calcium seems to reduce levels of dolutegravir.
Read the full Calcium + Dolutegravir, Emtricitabine, Tenofovir Alafenamide interactionDolutegravir, RilpivirineJuluca
How Dolutegravir, Rilpivirine interacts with B1 100 mg — through 1 ingredient. Tap an ingredient for the detail:
CalciumDolutegravir (tivicay) Major
Interaction Summary
Calcium seems to reduce levels of dolutegravir.
Read the full Calcium + Dolutegravir, Rilpivirine interactionElvitegravirVitekta
How Elvitegravir interacts with B1 100 mg — through 1 ingredient. Tap an ingredient for the detail:
CalciumElvitegravir (vitekta) Major
Interaction Summary
Calcium seems to reduce levels of elvitegravir.
Read the full Calcium + Elvitegravir interactionElvitegravir, Cobicistat, Emtricitabine, Tenofovir Disoproxil FumarateStribild
How Elvitegravir, Cobicistat, Emtricitabine, Tenofovir Disoproxil Fumarate interacts with B1 100 mg — through 1 ingredient. Tap an ingredient for the detail:
CalciumElvitegravir (vitekta), Bictegravir/emtricitabine/tenofovir Alafenamide (biktarvy) Major
Interaction Summary
Calcium seems to reduce levels of elvitegravir.
Read the full Calcium + Elvitegravir, Cobicistat, Emtricitabine, Tenofovir Disoproxil Fumarate interactionAlendronateBinosto, Fosamax
How Alendronate interacts with B1 100 mg — through 1 ingredient. Tap an ingredient for the detail:
CalciumBisphosphonates Moderate
Interaction Summary
Calcium reduces the absorption of bisphosphonates.
Read the full Calcium + Alendronate interactionAlendronate Sodium
How Alendronate Sodium interacts with B1 100 mg — through 1 ingredient. Tap an ingredient for the detail:
CalciumBisphosphonates Moderate
Interaction Summary
Calcium reduces the absorption of bisphosphonates.
Read the full Calcium + Alendronate Sodium interactionAlendronate Sodium, CholecalciferolFosamax Plus D
How Alendronate Sodium, Cholecalciferol interacts with B1 100 mg — through 1 ingredient. Tap an ingredient for the detail:
CalciumBisphosphonates Moderate
Interaction Summary
Calcium reduces the absorption of bisphosphonates.
Read the full Calcium + Alendronate Sodium, Cholecalciferol interactionAlginic Acid, Aluminum HydroxideRafton
How Alginic Acid, Aluminum Hydroxide interacts with B1 100 mg — through 1 ingredient. Tap an ingredient for the detail:
CalciumAluminum Moderate
Interaction Summary
Calcium citrate might increase aluminum absorption and toxicity.
Read the full Calcium + Alginic Acid, Aluminum Hydroxide interactionAluminum Acetate, Benzethonium ChlorideBuro-Sol Otic Solution
How Aluminum Acetate, Benzethonium Chloride interacts with B1 100 mg — through 1 ingredient. Tap an ingredient for the detail:
CalciumAluminum Moderate
Interaction Summary
Calcium citrate might increase aluminum absorption and toxicity.
Read the full Calcium + Aluminum Acetate, Benzethonium Chloride interactionAluminum ChlorideAluminum Chloride, Anhydrol Forte, Driclor, Drysol
How Aluminum Chloride interacts with B1 100 mg — through 1 ingredient. Tap an ingredient for the detail:
CalciumAluminum Moderate
Interaction Summary
Calcium citrate might increase aluminum absorption and toxicity.
Read the full Calcium + Aluminum Chloride interactionAluminum HydroxideAlu-Cap, Amphojel, Gaviscon
How Aluminum Hydroxide interacts with B1 100 mg — through 1 ingredient. Tap an ingredient for the detail:
CalciumAluminum Moderate
Interaction Summary
Calcium citrate might increase aluminum absorption and toxicity.
Read the full Calcium + Aluminum Hydroxide interactionAluminum Hydroxide, Aspirin, Codeine Phosphate, Magnesium HydroxideAscriptin Codeine #2
How Aluminum Hydroxide, Aspirin, Codeine Phosphate, Magnesium Hydroxide interacts with B1 100 mg — through 1 ingredient. Tap an ingredient for the detail:
CalciumAluminum Moderate
Interaction Summary
Calcium citrate might increase aluminum absorption and toxicity.
Read the full Calcium + Aluminum Hydroxide, Aspirin, Codeine Phosphate, Magnesium Hydroxide interactionAluminum Hydroxide, Aspirin, Magnesium HydroxideAscriptin
How Aluminum Hydroxide, Aspirin, Magnesium Hydroxide interacts with B1 100 mg — through 1 ingredient. Tap an ingredient for the detail:
CalciumAluminum Moderate
Interaction Summary
Calcium citrate might increase aluminum absorption and toxicity.
Read the full Calcium + Aluminum Hydroxide, Aspirin, Magnesium Hydroxide interactionAluminum Hydroxide, Magnesium Hydroxide (otc Drug)Maalox, Mucogel
How Aluminum Hydroxide, Magnesium Hydroxide (otc Drug) interacts with B1 100 mg — through 1 ingredient. Tap an ingredient for the detail:
CalciumAluminum Moderate
Interaction Summary
Calcium citrate might increase aluminum absorption and toxicity.
Read the full Calcium + Aluminum Hydroxide, Magnesium Hydroxide (otc Drug) interactionAluminum Hydroxide, Magnesium Hydroxide, Simethicone (otc Drug)Mylanta
How Aluminum Hydroxide, Magnesium Hydroxide, Simethicone (otc Drug) interacts with B1 100 mg — through 1 ingredient. Tap an ingredient for the detail:
CalciumAluminum Moderate
Interaction Summary
Calcium citrate might increase aluminum absorption and toxicity.
Read the full Calcium + Aluminum Hydroxide, Magnesium Hydroxide, Simethicone (otc Drug) interactionAluminum, CalciumDomeboro
How Aluminum, Calcium interacts with B1 100 mg — through 1 ingredient. Tap an ingredient for the detail:
CalciumAluminum Moderate
Interaction Summary
Calcium citrate might increase aluminum absorption and toxicity.
Read the full Calcium + Aluminum, Calcium interactionAluminum, Magnesium (otc Drug)Almagel
How Aluminum, Magnesium (otc Drug) interacts with B1 100 mg — through 1 ingredient. Tap an ingredient for the detail:
CalciumAluminum Moderate
Interaction Summary
Calcium citrate might increase aluminum absorption and toxicity.
Read the full Calcium + Aluminum, Magnesium (otc Drug) interactionAluminum, Magnesium Hydroxide (otc Drug)Wingel
How Aluminum, Magnesium Hydroxide (otc Drug) interacts with B1 100 mg — through 1 ingredient. Tap an ingredient for the detail:
CalciumAluminum Moderate
Interaction Summary
Calcium citrate might increase aluminum absorption and toxicity.
Read the full Calcium + Aluminum, Magnesium Hydroxide (otc Drug) interactionAmiloride, HydrochlorothiazideAmil-Co, Amilzide, Moduret 25, Moduretic
How Amiloride, Hydrochlorothiazide interacts with B1 100 mg — through 1 ingredient. Tap an ingredient for the detail:
CalciumThiazide Diuretics Moderate
Interaction Summary
Taking calcium along with thiazides might increase the risk of hypercalcemia and renal failure.
Read the full Calcium + Amiloride, Hydrochlorothiazide interactionAmphotericin, TetracyclineMysteclin-F
How Amphotericin, Tetracycline interacts with B1 100 mg — through 1 ingredient. Tap an ingredient for the detail:
CalciumTetracycline Antibiotics Moderate
Interaction Summary
Calcium seems to reduce the absorption of tetracycline antibiotics.
Read the full Calcium + Amphotericin, Tetracycline interactionAspirin, Aluminum Hydroxide, Codeine Phosphate, Magnesium HydroxideAscriptin Codeine #3
How Aspirin, Aluminum Hydroxide, Codeine Phosphate, Magnesium Hydroxide interacts with B1 100 mg — through 1 ingredient. Tap an ingredient for the detail:
CalciumAluminum Moderate
Interaction Summary
Calcium citrate might increase aluminum absorption and toxicity.
Read the full Calcium + Aspirin, Aluminum Hydroxide, Codeine Phosphate, Magnesium Hydroxide interactionAtenolol, ChlortalidoneAtenixCo, Tenoret 50, Totaretic
How Atenolol, Chlortalidone interacts with B1 100 mg — through 1 ingredient. Tap an ingredient for the detail:
CalciumThiazide Diuretics Moderate
Interaction Summary
Taking calcium along with thiazides might increase the risk of hypercalcemia and renal failure.
Read the full Calcium + Atenolol, Chlortalidone interactionAtenolol, ChlorthalidoneTenoretic
How Atenolol, Chlorthalidone interacts with B1 100 mg — through 1 ingredient. Tap an ingredient for the detail:
CalciumThiazide Diuretics Moderate
Interaction Summary
Taking calcium along with thiazides might increase the risk of hypercalcemia and renal failure.
Read the full Calcium + Atenolol, Chlorthalidone interactionAzilsartan, ChlorthalidoneEdarbyclor
How Azilsartan, Chlorthalidone interacts with B1 100 mg — through 1 ingredient. Tap an ingredient for the detail:
CalciumThiazide Diuretics Moderate
Interaction Summary
Taking calcium along with thiazides might increase the risk of hypercalcemia and renal failure.
Read the full Calcium + Azilsartan, Chlorthalidone interactionBenazepril, HydrochlorothiazideLotensin HCT
How Benazepril, Hydrochlorothiazide interacts with B1 100 mg — through 1 ingredient. Tap an ingredient for the detail:
CalciumThiazide Diuretics Moderate
Interaction Summary
Taking calcium along with thiazides might increase the risk of hypercalcemia and renal failure.
Read the full Calcium + Benazepril, Hydrochlorothiazide interactionBendroflumethiazideAprinox, Naturetin, Neo-NaClex
How Bendroflumethiazide interacts with B1 100 mg — through 1 ingredient. Tap an ingredient for the detail:
CalciumThiazide Diuretics Moderate
Interaction Summary
Taking calcium along with thiazides might increase the risk of hypercalcemia and renal failure.
Read the full Calcium + Bendroflumethiazide interactionBendroflumethiazide, NadololCorzide
How Bendroflumethiazide, Nadolol interacts with B1 100 mg — through 1 ingredient. Tap an ingredient for the detail:
CalciumThiazide Diuretics Moderate
Interaction Summary
Taking calcium along with thiazides might increase the risk of hypercalcemia and renal failure.
Read the full Calcium + Bendroflumethiazide, Nadolol interactionEach ingredient & the kinds of drugs it affects
For each ingredient in B1 100 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.
Calcium
Ceftriaxone (Rocephin)
Co-administration of intravenous calcium and ceftriaxone can result in precipitation of a ceftriaxone-calcium salt in the lungs and kidneys.
Avoid administering intravenous calcium in any form, such as parenteral nutrition or Lactated Ringers, within 48 hours of intravenous ceftriaxone. Case reports in neonates show that administering intravenous ceftriaxone and calcium can result in precipitation of a ceftriaxone-calcium salt in the lungs and kidneys. In several cases, neonates have died as a result of this interaction. So far there are no reports in adults; however, there is still concern that this interaction might occur in adults.
Dolutegravir (Tivicay)
Calcium seems to reduce levels of dolutegravir.
Advise patients to take dolutegravir either 2 hours before or 6 hours after taking calcium supplements. Pharmacokinetic research suggests that taking calcium carbonate 1200 mg concomitantly with dolutegravir 50 mg reduces plasma levels of dolutegravir by almost 40%. Calcium appears to decrease levels of dolutegravir through chelation.
Elvitegravir (Vitekta)
Calcium seems to reduce levels of elvitegravir.
Advise patients to take elvitegravir either 2 hours before or 2 hours after taking calcium supplements. Pharmacokinetic research suggests that taking calcium along with elvitegravir can reduce blood levels of elvitegravir through chelation.
Aluminum
Calcium citrate might increase aluminum absorption and toxicity. Other types of calcium do not increase aluminum absorption.
Calcium citrate can increase the absorption of aluminum when taken with aluminum hydroxide. The increase in aluminum levels may become toxic, particularly in individuals with kidney disease. However, the effect of calcium citrate on aluminum absorption is due to the citrate anion rather than calcium cation. Calcium acetate does not appear to increase aluminum absorption.
Bictegravir/Emtricitabine/Tenofovir Alafenamide (Biktarvy)
Calcium might decrease levels of bictegravir/emtricitabine/tenofovir alafenamide by reducing its absorption when taken in a fasting state.
Advise patients that bictegravir/emtricitabine/tenofovir alafenamide and calcium can be taken together if taken with food. However, if taken on an empty stomach, bictegravir/emtricitabine/tenofovir alafenamide should not be taken with, or 2 hours after, calcium containing products.
Bisphosphonates
Calcium reduces the absorption of bisphosphonates.
Advise patients to take bisphosphonates at least 30 minutes before calcium, but preferably at a different time of day. Calcium supplements decrease absorption of bisphosphonates.
Calcipotriene (Dovonex)
Taking calcipotriene with calcium might increase the risk for hypercalcemia.
Calcipotriene is a vitamin D analog used topically for psoriasis. It can be absorbed in sufficient amounts to cause systemic effects, including hypercalcemia. Theoretically, combining calcipotriene with calcium supplements might increase the risk of hypercalcemia.
Digoxin (Lanoxin)
Using intravenous calcium with digoxin might increase the risk of fatal cardiac arrhythmias.
Hypercalcemia increases the risk of fatal cardiac arrhythmias with digoxin. However, one retrospective analysis of clinical data suggests that intravenous calcium does not increase the risk of dysrhythmias or mortality in patients receiving digoxin.
Diltiazem (Cardizem, Others)
Theoretically, calcium may reduce the therapeutic effects of diltiazem.
Hypercalcemia can reduce the effectiveness of verapamil in atrial fibrillation. Theoretically, calcium might increase this risk of hypercalcemia and reduce the effectiveness of diltiazem.
Levothyroxine (Synthroid, Others)
Calcium seems to reduce the absorption and effectiveness of levothyroxine.
Advise patients to take levothyroxine and calcium supplements at least 4 hours apart. Calcium reduces levothyroxine absorption, probably by forming insoluble complexes. Calcium carbonate supplements reduce effectiveness of levothyroxine in patients with hypothyroidism.
Lithium
Theoretically, concomitant use of calcium and lithium may increase this risk of hypercalcemia.
Clinical research suggests that long-term use of lithium may cause hypercalcemia in 10% to 60% of patients. Theoretically, concomitant use of lithium and calcium supplements may further increase this risk.
Quinolone Antibiotics
Calcium seems to reduce the absorption of quinolone antibiotics.
Advise patients to take oral quinolones at least 2 hours before or 4-6 hours after calcium supplements or calcium-fortified foods. Taking calcium at the same time as oral quinolones can reduce quinolone absorption. Calcium binds to quinolones in the gut.
Raltegravir (Isentress)
Calcium may reduce levels of raltegravir.
Pharmacokinetic research shows that taking a single dose of calcium carbonate 3000 mg along with raltegravir 400 mg twice daily modestly decreases the mean area under the curve of raltegravir, but the decrease does not necessitate a dose adjustment of raltegravir. However, a case of elevated HIV-1 RNA levels and documented resistance to raltegravir has been reported for a patient taking calcium carbonate 1 gram three times daily plus vitamin D3 (cholecalciferol) 400 IU three times daily in combination with raltegravir 400 mg twice daily for 11 months. It is thought that calcium reduced raltegravir levels by chelation, leading to treatment failure.
Sotalol (Betapace)
Calcium seems to reduce the absorption of sotalol.
Advise patients to separate doses by at least 2 hours before or 4-6 hours after calcium. Calcium appears to reduce the absorption of sotalol, probably by forming insoluble complexes.
Tetracycline Antibiotics
Calcium seems to reduce the absorption of tetracycline antibiotics.
Advise patients to take oral tetracyclines at least 2 hours before, or 4-6 hours after calcium supplements. Taking calcium at the same time as oral tetracyclines can reduce tetracycline absorption. Calcium binds to tetracyclines in the gut.
Thiazide Diuretics
Taking calcium along with thiazides might increase the risk of hypercalcemia and renal failure.
Thiazides reduce calcium excretion by the kidneys. Using thiazides along with moderately large amounts of calcium carbonate increases the risk of milk-alkali syndrome (hypercalcemia, metabolic alkalosis, renal failure). Patients may need to have their serum calcium levels and/or parathyroid function monitored regularly.
Verapamil (Calan, Others)
Theoretically, calcium may reduce the therapeutic effects of verapamil.
Hypercalcemia can reduce the effectiveness of verapamil in atrial fibrillation. Theoretically, use of calcium supplements may increase this risk of hypercalcemia and reduce the effectiveness of verapamil.
Calcium Channel Blockers
Intravenous calcium may decrease the effects of calcium channel blockers; oral calcium is unlikely to have this effect.
Intravenous calcium is used to decrease the effects of calcium channel blockers in the management of overdose. Intravenous calcium gluconate has been used before intravenous verapamil (Isoptin) to prevent or reduce the hypotensive effects without affecting the antiarrhythmic effects. But there is no evidence that dietary or supplemental calcium when taken orally interacts with calcium channel blockers.
Thiamine
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.
Brand information
Manufacturer and brand details for B1 100 mg, from the product label.
Nature Made
See all Nature Made products- Name
- Nature Made Nutritional Products
- City
- West Hills
- State
- CA
- ZipCode
- 91309-9903
- Phone Number
- 1-800-276-2878
- Web Address
- www.NatureMade.com
B1 100 mg by Nature Made: Common Questions
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Written and reviewed by the HelloPharmacist editorial staff. Our editorial policy
Not sure if B1 100 mg is safe with your meds?
Our pharmacists answer your medication & supplement questions — free.
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.
The Full Monographs Behind B1 100 mg’s Ingredients
Every ingredient we hold a full HelloPharmacist monograph for — uses, evidence, safety, and the complete interaction list.
Calcium
Interacts with 168 drugsCalcium is an essential mineral your body needs for strong bones, nerve signaling, and muscle function, and supplements can help fill gaps when diet falls short. Most people do best getting...
Read the full Calcium monograph → Herb & supplement monographThiamine
Interacts with 3 drugsThiamine (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 →Sources & How We Checked
B1 100 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.
- NIH Dietary Supplement Label Database (DSLD) — The official product label on file for this supplement.
- Natural Medicines (Therapeutic Research Center) — Evidence-graded clinical reference behind the ingredient interaction data.
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 69 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.
Calcium 62 references
- Shils M, Olson A, Shike M. Modern Nutrition in Health and Disease. 8th ed. Philadelphia, PA: Lea and Febiger, 1994.
- Hernandez-Avila M, Gonzalez-Cossio T, Hernandez-Avila JE, et al. Dietary calcium supplements to lower blood lead levels in lactating women: a randomized placebo-controlled trial. Epidemiology 2003;14:206-12.. PubMed
- Thys-Jacobs S, Ceccarelli S, Bierman A, et al. Calcium supplementation in premenstrual syndrome: a randomized crossover trial. J Gen Intern Med 1989;4:183-9. PubMed
- Maton PN, Burton ME. Antacids revisited: a review of their clinical pharmacology and recommended therapeutic use. Drugs 1999;57:855-70.
- Clemens JD, Feinstein AR. Calcium carbonate and constipation: a historical review of medical mythopoeia. Gastroenterology 1977;72:957-61. DOI
- Saunders D, Sillery J, Chapman R. Effect of calcium carbonate and aluminum hydroxide on human intestinal function. Dig Dis Sci 1988;33:409-13. PubMed
- Friedman PA, Bushinsky DA. Diuretic effects on calcium metabolism. Semin Nephrol 1999;19:551-6.
- Koo WK, Walters JC, Esterlitz J, et al. Maternal calcium supplementation and fetal bone mineralization. Obstet Gynecol 1999;94:577-82. DOI
- Raman L, Rajalakshmi K, Krishnamachari KAVR, et al. Effect of calcium supplementation to undernourished mothers during pregnancy on the bone density of the neonates. Am J Clin Nutr 1978; 31:466-9. DOI
- Murry JJ, Healy MD. Drug-mineral interactions: a new responsibility for the hospital dietician. J Am Diet Assoc 1991;91:66-73.
- Chan JM, Giovannucci E, Andersson SO, et al. Dairy products, calcium, phosphorous, vitamin D, and risk of prostate cancer. Cancer Causes Control 1998;9:559-66.
- Butner LE, Fulco PP, Feldman G, et al. Calcium carbonate-induced hypothyroidism. Ann Intern Med 2000:132:595. PubMed
- Schneyer CR. Calcium carbonate and reduction of levothyroxine efficacy. JAMA 1998;279:750. PubMed
- Moser LR, Smythe MA, Tisdale JE. The use of calcium salts in the prevention and management of verapamil-induced hypotension. Ann Pharmacother 2000;34:622-9. PubMed
- Singh N, Singh PN, Hershman JM. Effect of calcium carbonate on the absorption of levothyroxine. JAMA 2000;283:2822-5. PubMed
- Kahela P, Anttila M, Tikkanen R, Sundquist H. Effect of food, food constituents and fluid volume on the bioavailability of sotalol. Acta Pharmacol Toxicol (Copenh) 1979;44:7-12.. PubMed
- Pletz MW, Petzold P, Allen A, et al. Effect of calcium carbonate on bioavailability of orally administered gemifloxacin. Antimicrob Agents Chemother 2003;47:2158-60.. PubMed
- Bar-Or D, Yoel G. Calcium and calciferol antagonize effect of verapamil in atrial fibrillation. Br Med J 1981;282:1585-6.
- Decktor DL, Robinson M, Maton PN, et al. Effects of aluminum/magnesium hydroxide and calcium carbonate on esophageal and gastric pH in subjects with heartburn. Am J Ther 1995;2:546-52. PubMed
- Simoneau G. Absence of rebound effect with calcium carbonate. Eur J Drug Metab Pharmacokinet 1996;21:351-7. PubMed
- Peters ML, Leonard M, Licata AA. Role of alendronate and risedronate in preventing and treating osteoporosis. Cleve Clin J Med 2001;68:945-51. PubMed
- Bourke JF, Mumford R, Whittaker P, et al. The effects of topical calcipotriol on systemic calcium homeostasis in patients with chronic plaque psoriasis. J Am Acad Dermatol 1997;37:929-34.
- Gueguen L, Pointillart A. The bioavailability of dietary calcium. J Am Coll Nutr 2000;19:119s-136s. PubMed
- Vella A, Gerber TC, Hayes DL, Reeder GS. Digoxin, hypercalcaemia, and cardiac conduction. Postgrad Med J 1999;75:554-6. PubMed
- Bania TC, Blaufeux B, Hughes S, et al. Calcium and digoxin vs. calcium alone for severe verapamil toxicity. Acad Emerg Med 2000;7:1089-96. PubMed
- Tseng M, Breslow RA, Graubard BI, Ziegler RG. Dairy, calcium, and vitamin D intakes and prostate cancer risk in the National Health and Nutrition Examination Epidemiologic Follow-up Study cohort. Am J Clin Nutr 2005;81:1147-54. PubMed
- Weingarten MA, Zalmanovici A, Yaphe J. Dietary calcium supplementation for preventing colorectal cancer and adenomatous polyps. Cochrane Database Syst Rev 2004;(1):CD003548. PubMed
- Tavani A, Bertuccio P, Bosetti C, et al. Dietary intake of calcium, vitamin D, phosphorus and the risk of prostate cancer. Eur Urol 2005;48:27-33. PubMed
- Giovannucci E, Liu Y, Stampfer MJ, Willett WC. A prospective study of calcium intake and incident and fatal prostate cancer. Cancer Epidemiol Biomarkers Prev 2006;15:203-10. PubMed
- Rocephin (ceftriaxone) and calcium interaction. Pharmacist's Letter / Prescriber's Letter 2007;23(10):231005.
- Bolland MJ, Barber PA, Doughty RN, et al. Vascular events in healthy older women receiving calcium supplementation: randomised control trial. BMJ 2008;336:262-6.
- Bolland MJ, Avenell A, Baron JA, et al. Effect of calcium supplements on risk of myocardial infarction and cardiovascular events: meta-analysis. BMJ 2010;341:c3691. PubMed
- Calcium supplementation and vascular events. Pharmacist's Letter / Prescriber's Letter 2008;24(3):240306.
- Dietary reference intakes for calcium and vitamin D. Institute of Medicine, November 30, 2010. Available at: http://www.iom.edu/~/media/Files/Report%20Files/2010/Dietary-Reference-Intakes-for-Calcium-and-Vitamin-D/Vitamin%20D%20and%20Calcium%202010%20Repo
- Coburn JW, Mischel MG, Goodman WG, et al. Calcium citrate markedly enhances aluminum absorption from aluminum hydroxide. Am J Kidney Dis. 1991;17(6):708-11. PubMed
- Bradley JS, Wassel RT, Lee L, et al. Intravenous ceftriaxone and calcium in the neonate: assessing the risk for cardiopulmonary adverse events. Pediatrics. 2009;123(4):e609-13. PubMed
- Kays MB, Overholser BR, Mueller BA, et al. Effects of sevelamer hydrochloride and calcium acetate on the oral bioavailability of ciprofloxacin. Am J Kidney Dis. 2003;42(6):1253-9. PubMed
- Neuhofel, A. L., Wilton, J. H., Victory, J. M., Hejmanowsk, L. G., and Amsden, G. W. Lack of bioequivalence of ciprofloxacin when administered with calcium-fortified orange juice: a new twist on an old interaction. J Clin Pharmacol. 2002;42(4):461-466. DOI
- Dickinson, H. O., Nicolson, D. J., Cook, J. V., Campbell, F., Beyer, F. R., Ford, G. A., and Mason, J. Calcium supplementation for the management of primary hypertension in adults. Cochrane.Database.Syst.Rev. 2006;(2):CD004639. PubMed
- Jones, B. J. and Twomey, P. J. Requesting patterns for serum calcium concentration in patients on long-term lithium therapy. Int J Clin Pract. 2009;63(1):170-172. PubMed
- Levine, M., Nikkanen, H., and Pallin, D. J. The effects of intravenous calcium in patients with digoxin toxicity. J Emerg.Med. 2011;40(1):41-46. PubMed
- Castelo-Branco, C., Ciria-Recasens, M., Cancelo-Hidalgo, M. J., Palacios, S., Haya-Palazuelos, J., Carbonell-Abello, J., Blanch-Rubio, J., Martinez-Zapata, M. J., Manasanch, J., and Perez-Edo, L. Efficacy of ossein-hydroxyapatite complex compared with ca
- Li K, Kaaks R, Linseisen J, Rohrmann S. Associations of dietary calcium intake and calcium supplementation with myocardial infarction and stroke risk and overall cardiovascular mortality in the Heidelberg cohort of the European Prospective Investigation i
- Chung M, Tang AM, Fu Z. Calcium Intake and Cardiovascular Disease Risk: An Updated Systematic Review and Meta-analysis. Ann Intern Med. 2016 Oct 25. PubMed
- Nolan CR, Califano JR, Butzin CA. Influence of calcium acetate or calcium citrate on intestinal aluminum absorption. Kidney Int. 1990;38(5):937-41. PubMed
- Lewis JR, Radavelli-Bagatini S, Rejnmark L, et al. The effects of calcium supplementation on verified coronary heart disease hospitalization and death in postmenopausal women: a collaborative meta-analysis of randomized controlled trials. J Bone Miner Res PubMed
- Jalloh MA, Gregory PJ, Hein D, et al. Dietary supplement interactions with antiretrovirals: a systematic review. Int J STD AIDS. 2017 Jan;28(1):4-15. PubMed
- Lappe J, Watson P, Travers-Gustafson D, Recker R, Garland C, Gorham E, Baggerly K, McDonnell SL. Effect of Vitamin D and Calcium Supplementation on Cancer Incidence in Older Women: A Randomized Clinical Trial. JAMA. 2017 Mar 28;317(12):1234-1243. PubMed
- Grove ML, Cook D. Calcium and heart attacks. Doesn't apply to most calcium prescriptions. BMJ. 2010;341:c5003. PubMed
- Insentress [package insert]. Whitehouse Station, NJ: Merck Sharp & Dohme Corp.; 2014.
- Roberts JL, Kiser JJ, Hindman JT, Meditz AL. Virologic failure with a raltegravir-containing antiretroviral regimen and concomitant calcium administration. Pharmacotherapy 2011;31(10):298e-302e. DOI
- Vitekta [package insert]. Foster City, CA: Gilead Sciences, Inc.; 2014.
- Storan ER, O'Gorman SM, Murphy A, Laing M. Case Report of Calciphylaxis Secondary to Calcium and Vitamin D<sub>3</sub> Supplementation. J Cutan Med Surg. 2017;21(2):162-163. DOI
- Jenkins DJA, Spence JD, Giovannucci EL, et al. Supplemental vitamins and minerals for CVD prevention and treatment. J Am Coll Cardiol 2018;71(22):2570-84. PubMed
- Borkenhagen JF, Connor EL, Stafstrom CE. Neonatal hypocalcemic seizures due to excessive maternal calcium ingestion. Pediatr Neurol 2013;48(6):469-71. PubMed
- WHO recommendations on antenatal care for a positive pregnancy experience. Geneva: World Health Organization; 2016 (http://www.who.int/reproductivehealth/publications/maternal_perinatal_health/ anc-positive-pregnancy-experience/en/).
- Aune D, Navarro Rosenblatt DA, Chan DS, et al. Dairy products, calcium, and prostate cancer risk: a systematic review and meta-analysis of cohort studies. Am J Clin Nutr. 2015;101(1):87-117. PubMed
- Lan T, Park Y, Colditz GA, et al. Adolescent dairy product and calcium intake in relation to later prostate cancer risk and mortality in the NIH-AARP Diet and Health Study. Cancer Causes Control. 2020;31(10):891-904. PubMed
- Zhang Y, Li Y, Liu J, et al. Association of Vitamin D or Calcium Supplementation with Cardiovascular Outcomes and Mortality: A Meta-Analysis with Trial Sequential Analysis. J Nutr Health Aging 2021;25(2):263-270. PubMed
- Myung SK, Kim HB, Lee YJ, Choi YJ, Oh SW. Calcium Supplements and Risk of Cardiovascular Disease: A Meta-Analysis of Clinical Trials. Nutrients 2021;13(2):368. PubMed
- Hetaimish B. Neonatal Calcinosis Cutis After Treatment of Hypocalcemia with Calcium Gluconate: A Report of 2 Cases. Am J Case Rep 2024;25:e943397. PubMed
- 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.
Thiamine 7 references
- 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.
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.
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