Osteo-Guard Ingredients & Drug Interactions
What is this page for?
First and foremost: checking Osteo-Guard 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
Osteo-Guard is a dietary supplement by Douglas Laboratories with 4 active ingredients. Its ingredients are commonly taken for supporting normal blood clotting, bone health, heart and vascular health.Based on those ingredients, 170 medications have a known interaction with it, the most serious rated major. The ingredients most likely to interact are Calcium, Vitamin K1. Use the checker below to test your specific medication, or read the full HelloPharmacist Interaction Report.
Check Your Meds Against Osteo-Guard by Douglas Laboratories
Ask about any prescription or over-the-counter medication and we check it for interactions with Osteo-Guard by Douglas Laboratories — 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 Osteo-Guard by Douglas Laboratories
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
Osteo-Guard contains four active ingredients designed to support bone health. Vitamin K1 (phytonadione) is a fat-soluble vitamin involved in bone mineralization and blood clotting.
Boron is a trace mineral that may help maintain bone density. Calcium is the primary structural mineral in bone.
The product also includes phosphorus, though we hold no detailed data on it. Beyond these actives, the tablet contains several inactive ingredients—cellulose, hydroxypropyl methylcellulose, croscarmellose sodium, vegetable stearate, silica, water, polyethylene glycol, magnesium silicate, polystyrene, and polysorbate 80—which serve as binders, flow agents, and coating materials.
Does it work?
Strong evidence
Vitamin K1 is effective for correcting vitamin K deficiency and supporting blood clotting factors, and it's possibly effective for osteoporosis. Calcium is likely effective for osteoporosis and effective for treating low calcium levels and certain kidney conditions.
Boron is likely effective for boron deficiency and possibly effective for vaginal yeast infections and radiation skin damage, though it showed no benefit in one study of athletic performance. We hold no effectiveness data for phosphorus in this product.
How safe is it?
Well-documented data
Vitamin K1 taken by mouth is generally well tolerated, though it can cause mild gastrointestinal upset—nausea, diarrhea, and stomach discomfort—in some people. Calcium is well tolerated at recommended doses and may cause constipation, bloating, or mild stomach upset; very high doses have raised theoretical concerns about kidney stones and, in some studies, cardiovascular or prostate health, though the evidence is mixed.
Boron is well tolerated at low doses but at high doses can cause skin problems, hair loss, and in severe cases, poisoning with nausea, vomiting, and serious organ effects. Pregnancy and lactation: Vitamin K1 is likely safe in pregnancy and lactation.
Calcium is likely safe in pregnancy and lactation at recommended amounts. Boron safety data advises against supplemental use in pregnancy due to possible fetal harm, and we advise against boron supplements while breastfeeding because safety data is limited.
No pregnancy or lactation data is on file for phosphorus.
Meds to double-check
Major interaction found
Before taking Osteo-Guard, double-check with your doctor or pharmacist if you take warfarin or any blood thinner (Major concern with vitamin K1); HIV integrase inhibitors like dolutegravir or elvitegravir, or the antibiotic ceftriaxone by IV (Major concerns with calcium); levothyroxine, sotalol, raltegravir, calcipotriene, or diltiazem (Moderate concerns with calcium). Timing or dose adjustments may be needed, or your provider may recommend a different supplement.
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.
Osteo-Guard may be worth considering if you're at risk for or have been diagnosed with osteoporosis and don't take blood thinners, HIV medications, thyroid drugs, or certain heart medications. If you take warfarin or any HIV integrase inhibitor, this product is not appropriate for you.
Talk with your doctor or pharmacist about whether this supplement fits your individual health situation and medications before you start.
Educational only — not medical advice; always confirm with your pharmacist. Our editorial policy · How we use AI
Assessment coverage: 3 of 4 active ingredients matched to our full ingredient reviews (monographs). Based on the product label dated Mar 25, 2014.
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 Osteo-Guard, straight from the product label.
| Brand | Douglas Laboratories |
|---|---|
| Barcode (UPC) | 745287040119 |
| Net contents | 120 Tablet(s) |
| Market status | On market |
| Date entered into DSLD | Mar 25, 2014 |
| DSLD ID | 31336 |
| Product type | Other Combinations |
| Supplement form | Tablet Or Pill |
| Dietary claims / uses | Nutrient, All Other |
| Intended target group(s) | Adult (18 - 50 Years) |
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 Osteo-Guard by Douglas Laboratories, sourced from the NIH Dietary Supplement Label Database.
Supplement Facts
| Ingredient | Amount | % DV |
|---|---|---|
| Vitamin K1 | 15 mcg | 19% |
| Boron | 0.5 mg | -- |
| Calcium | 250 mg | 25% |
| Phosphorus | 120 mg | 12% |
Other ingredients: Cellulose, Hydroxypropyl Methylcellulose, Croscarmellose Sodium, Vegetable Stearate, Silica, Water, Polyethylene Glycol, Magnesium Silicate, (poly) ethenol, Polysorbate 80
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.
Formula
Osteo-Guard(R) provides calcium and phosphate from young bovine bone (as microcrystalline hydroxyapatite), trace minerals, bone matrix proteins, amino acids and glycosaminoglycans in their natural forms and physiologic ratios found in whole bone.
WARNING: This product contains Vitamin K, which intereferes with the prescription drugs Coumadin and Warfarin.
Suggested/Recommended/Usage/Directions
Suggested Usage: As a dietary supplement, adults take 1 tablet daily with food or as directed by your healthcare professional.
Precautions
WARNING: This product contains Vitamin K, which intereferes with the prescription drugs Coumadin and Warfarin. Do not take this if taking either of these drugs.
KEEP OUT OF REACH OF CHILDREN.
Tamper resistant package, do not use if outer seal is missing.
Storage
.For optimal storage conditions, store in a cool, dry place. (59(0) - 77(0)F/15(0) - 25(0)C) (35-65% relative humidity)
General
OSG
FDA Statement of Identity
A Dietary Supplement
Is this label outdated? Report a formula or label change and our pharmacy team will review it.
Osteo-Guard by Douglas Laboratories 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 Osteo-Guard by Douglas Laboratories
These are the 4 active ingredients this product is made of. Select any to open its full monograph.
Serving size1 Tablet(s) Dosage formTablet Or Pill Servings per container120 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.
Vitamin K1
Interacts with2 drugs
Vitamin K is an essential nutrient your body needs for normal blood clotting and to support healthy bones. Most people get enough from food, but suppl...
Vitamin K1 monograph & interactionsBoron
No knowninteractions
Boron is a trace mineral found in many plant foods and sold as a supplement, mainly promoted for bone, joint, and hormone health. The human evidence f...
Boron monograph & interactionsCalcium
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 & interactionsPhosphorus
Other (inactive) ingredients: Cellulose, Hydroxypropyl Methylcellulose, Croscarmellose Sodium, Vegetable Stearate, Silica, Water, Polyethylene Glycol, Magnesium Silicate, (poly) ethenol, Polysorbate 80. These complete the product’s ingredient list but are not active constituents.
Osteo-Guard by Douglas Laboratories Drug Interactions
HelloPharmacist Interaction Report
Osteo-Guard by Douglas Laboratories does interact with medications, primarily through its vitamin K1 and calcium content.
The most serious interaction is between vitamin K1 and warfarin (an anticoagulant or blood thinner), which is a Major severity concern — vitamin K can reverse warfarin's ability to thin your blood, potentially raising your clot risk.
Read the full breakdown — every affected drug type, severity by severity
Calcium in this product carries Major interactions with three HIV integrase inhibitors: dolutegravir, elvitegravir, and the antibiotic ceftriaxone (when given intravenously). Calcium can significantly lower blood levels of these HIV drugs or cause dangerous precipitation in the kidneys and lungs.
Calcium also has Moderate interactions with levothyroxine (thyroid medication), sotalol (a heart rhythm drug), raltegravir (another HIV integrase inhibitor), calcipotriene (a psoriasis medication), and diltiazem (a calcium channel blocker for heart and blood pressure).
Boron, another ingredient, has no interactions documented in our data. We could not check phosphorus — we hold no data for it.
Altogether, these interactions span 170 individual medications. Use the search tool below to verify your exact prescriptions before starting this product.
Check your own medications below · Editorial policy · How we use AI
Want to check YOUR meds against Osteo-Guard?
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 Osteo-Guard interact with 170 drugs. Click any drug to see the details.
2 of the 4 ingredients in Osteo-Guard interact with drugs. Each result below shows which ingredient is responsible. Calcium Vitamin K1
BendroflumethiazideAprinox, Naturetin, Neo-NaClex
How Bendroflumethiazide interacts with Osteo-Guard — 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 Osteo-Guard — 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 interactionBendroflumethiazide, PotassiumCentyl K, Neo-NaClex-K
How Bendroflumethiazide, Potassium interacts with Osteo-Guard — 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, Potassium interactionBendroflumethiazide, Rauwolfia SerpentinaRauzide
How Bendroflumethiazide, Rauwolfia Serpentina interacts with Osteo-Guard — 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, Rauwolfia Serpentina interactionBenzthiazideExna
How Benzthiazide interacts with Osteo-Guard — 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 + Benzthiazide interactionBetamethasone Dipropionate, CalcipotrieneEnstilar, Wynzora
How Betamethasone Dipropionate, Calcipotriene interacts with Osteo-Guard — through 1 ingredient. Tap an ingredient for the detail:
CalciumCalcipotriene (dovonex) Moderate
Interaction Summary
Taking calcipotriene with calcium might increase the risk for hypercalcemia.
Read the full Calcium + Betamethasone Dipropionate, Calcipotriene interactionBictegravir, Emtricitabine, Tenofovir AlafenamideBiktarvy
How Bictegravir, Emtricitabine, Tenofovir Alafenamide interacts with Osteo-Guard — through 1 ingredient. Tap an ingredient for the detail:
CalciumBictegravir/emtricitabine/tenofovir Alafenamide (biktarvy) Moderate
Interaction Summary
Calcium might decrease levels of bictegravir/emtricitabine/tenofovir alafenamide by reducing its absorption when taken in a fasting state.
Read the full Calcium + Bictegravir, Emtricitabine, Tenofovir Alafenamide interactionBismuth Subsalicylate, Metronidazole, TetracyclineHelidac
How Bismuth Subsalicylate, Metronidazole, Tetracycline interacts with Osteo-Guard — 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 + Bismuth Subsalicylate, Metronidazole, Tetracycline interactionBisoprolol, HydrochlorothiazideZiac
How Bisoprolol, Hydrochlorothiazide interacts with Osteo-Guard — 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 + Bisoprolol, Hydrochlorothiazide interactionCalcipotrieneDovonex
How Calcipotriene interacts with Osteo-Guard — through 1 ingredient. Tap an ingredient for the detail:
CalciumCalcipotriene (dovonex) Moderate
Interaction Summary
Taking calcipotriene with calcium might increase the risk for hypercalcemia.
Read the full Calcium + Calcipotriene interactionCandesartan Cilexetil, HydrochlorothiazideAtacand HCT
How Candesartan Cilexetil, Hydrochlorothiazide interacts with Osteo-Guard — 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 + Candesartan Cilexetil, Hydrochlorothiazide interactionCaptopril, HydrochlorothiazideAcezide, Capozide
How Captopril, Hydrochlorothiazide interacts with Osteo-Guard — 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 + Captopril, Hydrochlorothiazide interactionChlorothiazideDiuril
How Chlorothiazide interacts with Osteo-Guard — 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 + Chlorothiazide interactionChlorothiazide, MethyldopaAldochlor, Aldoclor 150, Aldoclor 250
How Chlorothiazide, Methyldopa interacts with Osteo-Guard — 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 + Chlorothiazide, Methyldopa interactionChlorothiazide, ReserpineDiupres
How Chlorothiazide, Reserpine interacts with Osteo-Guard — 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 + Chlorothiazide, Reserpine interactionChlortetracyclineAureomycin
How Chlortetracycline interacts with Osteo-Guard — 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 + Chlortetracycline interactionChlorthalidoneHygroton, Thalitone
How Chlorthalidone interacts with Osteo-Guard — 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 + Chlorthalidone interactionChlorthalidone, ClonidineClorpres, Combipres
How Chlorthalidone, Clonidine interacts with Osteo-Guard — 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 + Chlorthalidone, Clonidine interactionCinoxacinCinobac
How Cinoxacin interacts with Osteo-Guard — through 1 ingredient. Tap an ingredient for the detail:
CalciumQuinolone Antibiotics Moderate
Interaction Summary
Calcium seems to reduce the absorption of quinolone antibiotics.
Read the full Calcium + Cinoxacin interactionCiprofloxacinCiloxan, Cipro, Cipro IV, Cipro XR, Ciprobay, Otiprio
How Ciprofloxacin interacts with Osteo-Guard — through 1 ingredient. Tap an ingredient for the detail:
CalciumQuinolone Antibiotics Moderate
Interaction Summary
Calcium seems to reduce the absorption of quinolone antibiotics.
Read the full Calcium + Ciprofloxacin interactionClinafloxacinClinafloxacin
How Clinafloxacin interacts with Osteo-Guard — through 1 ingredient. Tap an ingredient for the detail:
CalciumQuinolone Antibiotics Moderate
Interaction Summary
Calcium seems to reduce the absorption of quinolone antibiotics.
Read the full Calcium + Clinafloxacin interactionCryptenamine, MethyclothiazideDiutensen
How Cryptenamine, Methyclothiazide interacts with Osteo-Guard — 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 + Cryptenamine, Methyclothiazide interactionCyclothiazideAnhydron, Fluidil
How Cyclothiazide interacts with Osteo-Guard — 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 + Cyclothiazide interactionDarunavir, Cobicistat, Emtricitabine, Tenofovir AlafenamideSymtuza
How Darunavir, Cobicistat, Emtricitabine, Tenofovir Alafenamide interacts with Osteo-Guard — through 1 ingredient. Tap an ingredient for the detail:
CalciumBictegravir/emtricitabine/tenofovir Alafenamide (biktarvy) Moderate
Interaction Summary
Calcium might decrease levels of bictegravir/emtricitabine/tenofovir alafenamide by reducing its absorption when taken in a fasting state.
Read the full Calcium + Darunavir, Cobicistat, Emtricitabine, Tenofovir Alafenamide interactionDemeclocyclineDeclomycin
How Demeclocycline interacts with Osteo-Guard — 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 + Demeclocycline interactionDeserpidine, HydrochlorothiazideOreticyl, Oreticyl Forte
How Deserpidine, Hydrochlorothiazide interacts with Osteo-Guard — 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 + Deserpidine, Hydrochlorothiazide interactionDeserpidine, MethyclothiazideEnduronyl, Enduronyl Forte
How Deserpidine, Methyclothiazide interacts with Osteo-Guard — 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 + Deserpidine, Methyclothiazide interactionDigoxinDigitek, Lanoxicaps, Lanoxin
How Digoxin interacts with Osteo-Guard — through 1 ingredient. Tap an ingredient for the detail:
CalciumDigoxin (lanoxin) Moderate
Interaction Summary
Using intravenous calcium with digoxin might increase the risk of fatal cardiac arrhythmias.
Read the full Calcium + Digoxin interactionDihydroxyaluminum Sodium CarbonateRolaids
How Dihydroxyaluminum Sodium Carbonate interacts with Osteo-Guard — 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 + Dihydroxyaluminum Sodium Carbonate interactionDiltiazemAdizem-SR, Adizem-XL, Angitil SR, Angitil XL, Calcicard CR, Cardizem +23 more
How Diltiazem interacts with Osteo-Guard — through 1 ingredient. Tap an ingredient for the detail:
CalciumCalcium Channel Blockers, Diltiazem (cardizem, Others) Moderate
Interaction Summary
Intravenous calcium may decrease the effects of calcium channel blockers; oral calcium is unlikely to have this effect.
Read the full Calcium + Diltiazem interactionEach ingredient & the kinds of drugs it affects
For each ingredient in Osteo-Guard 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.
Vitamin K1
Warfarin (Coumadin)
Vitamin K can antagonize and reverse the therapeutic effects of warfarin.
Vitamin K antagonizes the effects of warfarin. Excessive vitamin K intake, either from supplements or from changes in the diet, can reduce the anticoagulant effect of warfarin.
Brand information
Manufacturer and brand details for Osteo-Guard, from the product label.
Douglas Laboratories
See all Douglas Laboratories products- Name
- Douglas Laboratories
- Street Address
- 600 Boyce Road
- City
- Pittsburgh
- State
- PA
- ZipCode
- 15205
- Phone Number
- 1.800.245.4440
- Web Address
- www.douglaslabs.com
Osteo-Guard by Douglas Laboratories: Common Questions
Does Osteo-Guard by Douglas Laboratories interact with any medications?
How can one product interact with so many drugs?
Where does this information come from?
Will Osteo-Guard help my osteoporosis?
Can I take this if I'm pregnant?
Can I take this while breastfeeding?
What side effects might I notice?
Is this the same as taking calcium and vitamin K separately?
Why do I need to separate calcium from my thyroid medication?
Written and reviewed by the HelloPharmacist editorial staff. Our editorial policy
Not sure if Osteo-Guard is safe with your meds?
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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.
The Full Monographs Behind Osteo-Guard’s Ingredients
Every ingredient we hold a full HelloPharmacist monograph for — uses, evidence, safety, and the complete interaction list.
Vitamin K
Interacts with 2 drugsVitamin K is an essential nutrient your body needs for normal blood clotting and to support healthy bones. Most people get enough from food, but supplements are sometimes used for deficiency...
Read the full Vitamin K monograph → Herb & supplement monographBoron
Boron is a trace mineral found in many plant foods and sold as a supplement, mainly promoted for bone, joint, and hormone health. The human evidence for most of these uses is limited or prel...
Read the full Boron monograph → Herb & supplement monographCalcium
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 →Sources & How We Checked
Osteo-Guard'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 79 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.
Vitamin K 11 references
- McEvoy GK, ed. AHFS Drug Information. Bethesda, MD: American Society of Health-System Pharmacists, 1998.
- Food and Nutrition Board, Institute of Medicine. Dietary Reference Intakes for Vitamin A, Vitamin K, Arsenic, Boron, Chromium, Copper, Iodine, Iron, Manganese, Molybdenum, Nickel, Silicon, Vanadium, and Zinc. Washington, DC: National Academy Press, 2002.
- Crowther MA, Ageno W, Garcia D, et al. Oral vitamin K versus placebo to correct excessive anticoagulation in patients receiving warfarin: a randomized trial. Ann Intern Med. 2009;150(5):293-300. PubMed
- Dietary vitamin K guidance: an effective strategy for stable control of oral anticoagulation? Nutr Rev. 2010;68(3):178-81. PubMed
- Kim JS, Nafziger AN, Gaedigk A, et al. Effects of oral vitamin K on S- and R-warfarin pharmacokinetics and pharmacodynamics: enhanced safety of warfarin as a CYP2C9 probe. J Clin Pharmacol. 2001 Jul;41(7):715-22. PubMed
- Riegert-Johnson, D. L. and Volcheck, G. W. The incidence of anaphylaxis following intravenous phytonadione (vitamin K1): a 5-year retrospective review. Ann.Allergy Asthma Immunol. 2002;89(4):400-406. PubMed
- Dezee, K. J., Shimeall, W. T., Douglas, K. M., Shumway, N. M., and O'malley, P. G. Treatment of excessive anticoagulation with phytonadione (vitamin K): a meta-analysis. Arch.Intern.Med. 2-27-2006;166(4):391-397. DOI
- Dentali, F., Ageno, W., and Crowther, M. Treatment of coumarin-associated coagulopathy: a systematic review and proposed treatment algorithms. J.Thromb.Haemost. 2006;4(9):1853-1863. PubMed
- Caluwé R, Vandecasteele S, Van Vlem B, Vermeer C, De Vriese AS. Vitamin K2 supplementation in haemodialysis patients: a randomized dose-finding study. Nephrol Dial Transplant. 2014;29(7):1385-90.
- Huang ZB, Wan SL, Lu YJ, Ning L, Liu C, Fan SW. Does vitamin K2 play a role in the prevention and treatment of osteoporosis for postmenopausal women: a meta-analysis of randomized controlled trials. Osteoporos Int. 2015;26(3):1175-86. PubMed
- Hunnali CR, Devi U, Kitchanan S, Sethuraman G. Three Different Regimens for Vitamin K Birth Prophylaxis in Infants Born Preterm: A Randomized Clinical Trial. J Pediatr 2023;255:98-104. PubMed
Boron 6 references
- Ellenhorn MJ, et al. Ellenhorn's Medical Toxicology: Diagnoses and Treatment of Human Poisoning. 2nd ed. Baltimore, MD: Williams & Wilkins, 1997.
- Food and Nutrition Board, Institute of Medicine. Dietary Reference Intakes for Vitamin A, Vitamin K, Arsenic, Boron, Chromium, Copper, Iodine, Iron, Manganese, Molybdenum, Nickel, Silicon, Vanadium, and Zinc. Washington, DC: National Academy Press, 2002.
- Thai L, Hart LL. Boric acid vaginal suppositories. Ann Pharmacother 1993;27:1355-7.
- Acs N, Banhidy F, Puho E, Czeizel AE. Teratogenic effects of vaginal boric acid treatment during pregnancy. Int J Gynaecol Obstet 2006;93:55-6. PubMed
- Garabrant, D. H., Bernstein, L., Peters, J. M., and Smith, T. J. Respiratory and eye irritation from boron oxide and boric acid dusts. J Occup Med 1984;26(8):584-586. PubMed
- Hjelm C, Harari F, Vahter M. Pre- and postnatal environmental boron exposure and infant growth: results from a mother-child cohort in northern Argentina. Environ Res 2019;171:60-8. PubMed
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
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- 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
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- 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.
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