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

Calcium + D3 Ingredients & Drug Interactions

by Os-Cal

Calcium + D3 label
See full label image
Other (e.g. Tea Bag) Category: Single Vitamin And Mineral
Most serious interaction: Major
Clinical methodology reviewed by · Updated Sep 23, 2026 · Label data from the NIH DSLD
What is this page for?

First and foremost: checking Calcium + D3 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

Calcium + D3 is a dietary supplement by Os-Cal 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, 778 medications have a known interaction with it, the most serious rated major. The ingredients most likely to interact are Vitamin D3, Calcium. Use the checker below to test your specific medication, or read the full HelloPharmacist Interaction Report.

Jump to a section

Check Your Meds Against Calcium + D3 by Os-Cal

Ask about any prescription or over-the-counter medication and we check it for interactions with Calcium + D3 by Os-Cal — and tell you which ingredient is responsible.

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HelloPharmacist Scorecard of Calcium + D3 by Os-Cal

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 Jul 12, 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.

Os-Cal Calcium + D3 contains 2 active ingredients: calcium (the primary mineral for bone and tooth strength) and vitamin D3 (which helps your body absorb and use calcium effectively). Calcium is effective for treating low blood calcium (hypocalcemia), kidney failure, high potassium levels (hyperkalemia), heartburn (dyspepsia), and is likely effective for osteoporosis.

Vitamin D3 is effective for treating rickets, osteomalacia (soft bones), renal bone disease, low phosphate levels, and low parathyroid hormone — conditions where your body struggles to absorb calcium or regulate minerals properly. The product also contains several inactive ingredients (fillers, binders, and capsule materials), including calcium carbonate, corn syrup solids, talc, corn starch, and others that help form and preserve the supplement.

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: bone health and osteoporosis prevention.
  • We looked for evidence on: Corticosteroid-induced osteoporosis, Fractures, Hyperparathyroidism-related bone loss, Kidney transplant-related bone loss, Hypocalcemia, Hypoparathyroidism — and 4 related terms.
  • The strongest evidence on file: Calcium is rated "Effective" for Hypocalcemia (Natural Medicines).
  • Also on file: Vitamin D is rated "Effective" for Familial hypophosphatemia, Hypoparathyroidism.
  • Also on file: Calcium is rated "Likely Effective" for Corticosteroid-induced osteoporosis, Hyperparathyroidism, Osteoporosis.

Calcium is effective for low blood calcium, kidney failure, high potassium, and heartburn, and is likely effective for osteoporosis prevention and treatment. Vitamin D3 is effective for rickets, soft bones (osteomalacia), kidney bone disease, low phosphate levels, and low parathyroid hormone.

Together, they work because vitamin D3 is essential for your body to absorb the calcium and use it where it's needed.

The evidence, ingredient by ingredient Calcium Vitamin D

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.

Both calcium and vitamin D3 are generally well tolerated when you use the recommended amounts. The most common side effects of oral calcium are belching, constipation, diarrhea, gas, and stomach upset.

Vitamin D is generally well tolerated by mouth, but very high doses over time can cause vitamin D toxicity with symptoms of high blood calcium (hypercalcemia), kidney problems, or anemia. There is some concern that very high calcium intake (over 1500–2000 mg per day) might slightly increase the risk of prostate cancer and possibly cardiovascular disease, though the evidence is mixed and criticized by many experts.

Rare serious effects from calcium include kidney stones and a skin condition called calciphylaxis. In pregnancy, adequate calcium is important and this supplement is likely safe at recommended amounts — stay within those unless your doctor advises otherwise.

One vitamin D rating suggests it may be unsafe in pregnancy, so talk with your doctor before taking this product if you're pregnant or planning to become pregnant. During breastfeeding, calcium needs can be met and vitamin D is likely safe at recommended doses, but check with your provider before taking higher amounts.

Side effects, ingredient by ingredient Calcium Vitamin D

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 — Calcium, Vitamin D.
  • The most serious interaction on file is rated Major.
  • Some involve high-stakes drug classes: heart-rhythm medications; lithium.
  • For scale: 779 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 taking this product, check your medications against these drug types: HIV integrase inhibitors (dolutegravir, elvitegravir), IV ceftriaxone antibiotic, raltegravir, levothyroxine (thyroid hormone), sotalol, calcipotriene (psoriasis cream), diltiazem, thiazide diuretics (water pills), verapamil, digoxin, and atorvastatin. The severity ranges from Major (dolutegravir, elvitegravir, ceftriaxone) to Moderate (the others), so spacing and monitoring matter.

If you don't see your exact medication listed, use the checker below with your full prescription list.

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 supplement works well for correcting low calcium or vitamin D and for bone health, especially in older adults and those at risk for osteoporosis. If you take any prescription medications — particularly HIV drugs, thyroid hormone, heart rhythm medications, statins, or water pills — check each one with the tool on this page before starting.

Talk to your pharmacist about the right dose for you and the best timing if you're on other medications.

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 Sep 22, 2022.

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 Calcium + D3, straight from the product label.

Brand Os-Cal
Barcode (UPC) 30766-1656-752
Net contents 210 Coated Caplet(s)
Market status On market
Date entered into DSLD Sep 22, 2022
DSLD ID 272482
Product type Single Vitamin And Mineral
Supplement form Other (e.g. Tea Bag)
Dietary claims / uses Nutrient, All Other, Approved Health, Structure/Function
Intended target group(s) Adult (18 - 50 Years), Seniors/Mature (>50 Years), 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 Calcium + D3 by Os-Cal, 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 Caplet(s)
Maximum serving Sizes:
1 Caplet(s)
Servings per container
105
UPC/BARCODE
30766-1656-752
IngredientAmount% DV
Calcium500 mg50%
Vitamin D3200 IU50%

Other ingredients: Calcium Carbonate, Corn Syrup solids, Talc, Corn Starch, Sodium Starch Glyconate, Polysorbate 80, Polyvinyl Alcohol, Polyethylene Glycol 3350, Titanium Dioxide, Yellow 5 Lake, Blue 1 Lake, Calcium Stearate, Methylparaben, Propylparaben, Gelatin, Sucrose, Vitamin D3, DL-Alpha Tocopherol

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.
Formulation

Be strong with Os-Cal

May help reduce the risk of osteoporosis

Reasons to choose Os-Cal: Effective in helping maintain strong healthy bones Meets USP dissolution standards

This Os-Cal Calcium+D3 has no sugar, lactose, carbohydrates or sodium

Osteoporosis Adequate calcium and vitamin D as part of a healthful diet, along with physical activity, may reduce the risk of osteoporosis in later life.

FDA Statement of Identity

Calcium Supplement with Vitamin D3

Formula

500 mg calcium 200 IU vitamin D3

Adds a dietarily insignificant amount of sugar. Adds a dietarily insignificant amount of sodium. Each caplet provides 500 mg of elemental calcium.

Highly absorbable calcium

General Statements

Value size GSK

Questions or comments? call toll-free 1-800-2451040 (English/Spanish) weekdays

We value your feedback

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

Directions: Take one caplet, twice a day, with meals, or as recommended by your physician. Elderly patients or those with difficulty with swallowing are recommended to take the caplet with a large glass of water (8 oz) to minimize the risk of choking. Caplets may be broken in half. Can be taken along with your multivitamin.

Precautions

Elderly patients or those with difficulty with swallowing are recommended to take the caplet with a large glass of water (8 oz) to minimize the risk of choking.

Keep out of the reach of children.

Important: Do not use if foil inner seal printed "sealed for your protection" is disturbed or missing.

Storage

Store below 25 degrees C (77 degrees F). Keep container tightly closed.

Brand IP Statement(s)

Trademarks are owned by or licensed to the GSK group of companies. Copyright 2014 GSK group of companies or its licensor. All rights reserved.

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

See for yourself

Calcium + D3 by Os-Cal label

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

Calcium + D3 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 Calcium + D3 by Os-Cal

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

Serving size1 Caplet(s) Dosage formOther (e.g. Tea Bag) Servings per container105 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 with
168 drugs
500 mg per serving

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 & interactions

Vitamin D3

Interacts with
715 drugs
200 IU per serving

Vitamin D is a fat-soluble vitamin that helps your body absorb calcium and is important for healthy bones, muscles, and immune function. Many people,...

Vitamin D3 monograph & interactions

Other (inactive) ingredients: Calcium Carbonate, Corn Syrup solids, Talc, Corn Starch, Sodium Starch Glyconate, Polysorbate 80, Polyvinyl Alcohol, Polyethylene Glycol 3350, Titanium Dioxide, Yellow 5 Lake, Blue 1 Lake, Calcium Stearate, Methylparaben, Propylparaben, Gelatin, Sucrose, Vitamin D3, DL-Alpha Tocopherol. These complete the product’s ingredient list but are not active constituents.

Interaction report

Calcium + D3 by Os-Cal Drug Interactions

Want to check YOUR meds against Calcium + D3?

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
778Drugs
7 Major 146 Moderate 625 Minor

Ingredients driving the most interactions

Vitamin D3 715
Calcium 168

Individual Drug Interactions

The ingredients in Calcium + D3 interact with 778 drugs. Click any drug to see the details.

2 of the 2 ingredients in Calcium + D3 interact with drugs. Each result below shows which ingredient is responsible. Vitamin D3 Calcium

Each ingredient & the kinds of drugs it affects

For each ingredient in Calcium + D3 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.

Vitamin D38 drug types · 715 drugs

Aluminum

Vitamin D might increase aluminum absorption and toxicity, but this has only been reported in people with renal failure.
The protein that transports calcium across the intestinal wall can also bind and transport aluminum. This protein is stimulated by vitamin D, which may therefore increase aluminum absorption. This mechanism may contribute to increased aluminum levels and toxicity in people with renal failure, when they take vitamin D and aluminum-containing phosphate binders chronically.

Likelihood Probable Evidence B
Atorvastatin (Lipitor)

Vitamin D might reduce absorption of atorvastatin.
A small, low-quality clinical study shows that taking vitamin D reduces levels of atorvastatin and its active metabolites by up to 55%. However, while atorvastatin levels decreased, total cholesterol, low-density lipoprotein (LDL) cholesterol, and high-density lipoprotein (HDL) cholesterol levels did not substantially change. Atorvastatin is metabolized in the gut by CYP3A4 enzymes, and researchers theorized that vitamin D might induce CYP3A4, causing reduced levels of atorvastatin. However, this proposed mechanism was not specifically studied.

Likelihood Probable Evidence B
Calcipotriene (Dovonex)

Taking calcipotriene with vitamin D increases 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 vitamin D supplements might increase the risk of hypercalcemia.

Likelihood Probable Evidence D
Digoxin (Lanoxin)

Theoretically, hypercalcemia induced by high-dose vitamin D can increase the risk of arrhythmia from digoxin.
High doses of vitamin D can cause hypercalcemia. Hypercalcemia increases the risk of fatal cardiac arrhythmias with digoxin. Avoid vitamin D doses above the tolerable upper intake level (4000 IU daily for adults) and monitor serum calcium levels in people taking vitamin D and digoxin concurrently.

Likelihood Possible Evidence D
Diltiazem (Cardizem, Others)

Theoretically, hypercalcemia induced by high-dose vitamin D can reduce the therapeutic effects of diltiazem for arrhythmia.
High doses of vitamin D can cause hypercalcemia. Hypercalcemia can reduce the effectiveness of verapamil in atrial fibrillation. Theoretically this could also occur with diltiazem. Avoid vitamin D doses above the tolerable upper intake level (4000 IU daily for adults) and monitor serum calcium levels in people taking vitamin D and diltiazem concurrently.

Likelihood Probable Evidence B
Thiazide Diuretics

Theoretically, taking thiazide diuretics and high-dose vitamin D can increase the risk of hypercalcemia.
Thiazide diuretics decrease urinary calcium excretion, which could lead to hypercalcemia if vitamin D supplements are taken concurrently. This has been reported in people being treated with vitamin D for hypoparathyroidism, and also in elderly people with normal parathyroid function who were taking a thiazide, vitamin D, and calcium-containing antacids daily.

Likelihood Probable Evidence D
Verapamil (Calan, Others)

Hypercalcemia induced by high-dose vitamin D can reduce the therapeutic effects of verapamil for arrhythmia.
Hypercalcemia due to high doses of vitamin D can reduce the effectiveness of verapamil in atrial fibrillation. Avoid vitamin D doses above the tolerable upper intake level (4000 IU daily for adults) and monitor serum calcium levels in people taking vitamin D and verapamil concurrently.

Likelihood Probable Evidence B
Cytochrome P450 3A4 (Cyp3A4) Substrates

Vitamin D might induce CYP3A4 enzymes and reduce the bioavailability of CYP3A4 substrates.
There is some concern that vitamin D might induce CYP3A4. In vitro research suggests that vitamin D induces CYP3A4 transcription. Additionally, observational research has found that increased UV light exposure and serum vitamin D levels are associated with decreased serum levels of CYP3A4 substrates such as tacrolimus and sirolimus, while no association between UV light exposure or vitamin D levels and levels of mycophenolic acid, a non-CYP3A4 substrate, was found. A small, low-quality clinical study shows that taking vitamin D reduces levels of the CYP3A4 substrate atorvastatin and its active metabolites by up to 55%; however, the clinical effects of atorvastatin were not reduced. While researchers theorized that vitamin D might induce CYP3A4, this proposed mechanism was not specifically studied.

Likelihood Possible Evidence D
Vitamin D3 full monograph & interactions

Calcium18 drug types · 168 drugs

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.

Likelihood Probable Evidence D
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.

Likelihood Probable Evidence B
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.

Likelihood Probable Evidence B
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.

Likelihood Possible Evidence B
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.

Likelihood Probable Evidence D
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.

Likelihood Probable Evidence C
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.

Likelihood Possible Evidence B
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.

Likelihood Possible Evidence B
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.

Likelihood Probable Evidence D
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.

Likelihood Probable Evidence B
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.

Likelihood Possible Evidence B
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.

Likelihood Probable Evidence B
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.

Likelihood Possible Evidence B
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.

Likelihood Possible Evidence B
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.

Likelihood Probable Evidence C
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.

Likelihood Probable Evidence C
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.

Likelihood Probable Evidence D
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.

Likelihood Unlikely Evidence D
Calcium full monograph & interactions
The maker

Brand information

Manufacturer and brand details for Calcium + D3, from the product label.

Os-Cal

See all Os-Cal products
Name
GSK Consumer Healthcare
City
Warren
State
NJ
ZipCode
07059
Phone Number
1 800 245 1040
Web Address
www.oscal.com
Pharmacist Counseling Corner

Calcium + D3 by Os-Cal: Common Questions

Does Calcium + D3 by Os-Cal interact with any medications?
Yes. Based on its ingredients, Calcium + D3 has a known interaction with 778 medications, including 7 rated major. Use the checker to see how it interacts with a specific drug.
How can one product interact with so many drugs?
Calcium + D3 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 this safe to take if I'm pregnant?
Calcium is likely safe at recommended amounts during pregnancy — adequate calcium is important for both you and your baby. However, one rating for vitamin D suggests it may be unsafe in pregnancy. Talk with your doctor before starting this product if you're pregnant or planning pregnancy, so they can advise on the right dose for you.
Can I breastfeed while taking this supplement?
Yes. Calcium is safe at recommended doses during breastfeeding, and vitamin D3 is likely safe as well. Your calcium and vitamin D needs can be met with this supplement, but check with your doctor before taking higher amounts than recommended.
What are the most common side effects?
With oral calcium, you might notice belching, constipation, diarrhea, gas, or stomach upset. Vitamin D at recommended doses is usually well tolerated. If you have any of these side effects, tell your pharmacist — they may suggest taking it differently or recommend a different form.
How much calcium and vitamin D does each dose contain?
The product facts don't specify the amount of calcium or vitamin D per dose — check the label or ask your pharmacist for the exact dose so you can compare it to your daily needs.
Can too much of this supplement be harmful?
Yes. Very high doses of calcium over time (especially above 1500–2000 mg daily) may increase the risk of prostate cancer and possibly heart problems. Excessive vitamin D can cause toxicity with high blood calcium, kidney problems, and other serious effects. Stay within recommended amounts unless your doctor advises otherwise.
Does this work for osteoporosis?
Calcium is likely effective for osteoporosis, especially combined with vitamin D3, which helps your body absorb the calcium. Together they support bone strength, though talk with your doctor about whether this dose is right for your bone health and your personal risk.

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

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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.

Calcium + D3 label
Go deeper

The Full Monographs Behind Calcium + D3’s Ingredients

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

Herb & supplement monograph

Calcium

Interacts with 168 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 falls short. Most people do best getting...

Read the full Calcium monograph → Herb & supplement monograph

Vitamin D

Interacts with 715 drugs

Vitamin D is a fat-soluble vitamin that helps your body absorb calcium and is important for healthy bones, muscles, and immune function. Many people, especially those with low sun exposure,...

Read the full Vitamin D monograph →
Sources

Sources & How We Checked

Calcium + D3'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 88 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
  1. Shils M, Olson A, Shike M. Modern Nutrition in Health and Disease. 8th ed. Philadelphia, PA: Lea and Febiger, 1994.
  2. 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
  3. 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
  4. Maton PN, Burton ME. Antacids revisited: a review of their clinical pharmacology and recommended therapeutic use. Drugs 1999;57:855-70.
  5. Clemens JD, Feinstein AR. Calcium carbonate and constipation: a historical review of medical mythopoeia. Gastroenterology 1977;72:957-61. DOI
  6. 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
  7. Friedman PA, Bushinsky DA. Diuretic effects on calcium metabolism. Semin Nephrol 1999;19:551-6.
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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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