PB-4 Select Ingredients & Drug Interactions
What is this page for?
First and foremost: checking PB-4 Select 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
PB-4 Select is a dietary supplement by Moss Nutrition with 5 active ingredients. Its ingredients are commonly taken for bone health and osteoporosis, correcting vitamin d deficiency, immune system support.Based on those ingredients, 715 medications have a known interaction with it, the most serious rated moderate. The ingredients most likely to interact are Vitamin D3. Use the checker below to test your specific medication, or read the full HelloPharmacist Interaction Report.
Check Your Meds Against PB-4 Select by Moss Nutrition
Ask about any prescription or over-the-counter medication and we check it for interactions with PB-4 Select by Moss Nutrition — 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 PB-4 Select by Moss Nutrition
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
Low disclosure
PB-4 Select contains 5 active ingredients: vitamin D3 and four probiotic bacterial strains (L. plantarum KABP-022, L. plantarum KABP-023, L. plantarum KABP-033, and P. acidilactici KABP-21). Vitamin D3 supports bone health and calcium absorption; the probiotics are intended to support gut health.
The capsule also holds inactive ingredients — hydroxypropyl methylcellulose, maltodextrin, and vegetable stearate — which are fillers and binders.
Does it work?
Not established
Vitamin D3 is effective for several bone and mineral disorders: familial hypophosphatemia, osteomalacia (softening of the bones), renal osteodystrophy (bone disease from kidney disease), rickets, and hypoparathyroidism. The evidence for the probiotic strains in this product isn't on file in our data.
How safe is it?
Well-documented data
Vitamin D3 is generally well tolerated at recommended doses, but very high doses over time can cause toxicity with symptoms like high blood calcium, bone loss in adults, and slowed growth in children. At recommended amounts, it's often used in pregnancy, though you should use it only under your doctor's guidance.
At those standard doses it's generally considered acceptable during breastfeeding as well; if you're considering higher amounts, check with your doctor first. The safety data for the four probiotic strains isn't on file for us.
Meds to double-check
Moderate interaction found
Before you take this product, check with your doctor or pharmacist if you take digoxin or any heart-rhythm medication (verapamil, diltiazem), water pills (thiazide diuretics), atorvastatin or other cholesterol drugs, calcipotriene (a psoriasis cream), or any medication metabolized by your liver's CYP3A4 enzyme system. Moderate and minor interactions are documented.
The bottom line
Scorecard at a glanceFormula with limited ingredient disclosure with no established evidence rating for its marketed use. Moderate medication interactions have been identified, and safety information is well characterized.
This product is most appropriate for people with specific bone and mineral disorders — rickets, hypoparathyroidism, or osteomalacia — when prescribed by their doctor. If you take a heart medication (like digoxin, verapamil, or diltiazem), a water pill, a cholesterol drug, or any other regular medication, check it against vitamin D's interactions on this page before you start.
Talk with your doctor or pharmacist about whether PB-4 Select is right for you.
Educational only — not medical advice; always confirm with your pharmacist. Our editorial policy · How we use AI
Assessment coverage: 1 of 5 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
General information
Key facts about PB-4 Select, straight from the product label.
| Brand | Moss Nutrition |
|---|---|
| Barcode (UPC) | M161 |
| Net contents | 30 Vegetarian Capsule(s) |
| Market status | On market |
| Date entered into DSLD | Sep 22, 2022 |
| DSLD ID | 274246 |
| Product type | Other Combinations |
| Supplement form | Capsule |
| Dietary claims / uses | Nutrient, All Other |
| Intended target group(s) | Adult (18 - 50 Years), Gluten Free, Dairy 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 PB-4 Select by Moss Nutrition, sourced from the NIH Dietary Supplement Label Database.
Supplement Facts
| Ingredient | Amount | % DV |
|---|---|---|
| Vitamin D3 | 10 mcg | 50% |
| L. plantarum KABP-022 | 0 NP | -- |
| L. plantarum KABP-023 | 0 NP | -- |
| PB-4 Proprietary Probiotic Blend | 70 mg | -- |
| L. Plantarum KABP-033 | 0 NP | -- |
| P. acidilactici KABP-21 | 0 NP | -- |
Other ingredients: Hydroxypropyl Methylcellulose, Maltodextrin, Vegetable 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.
Brand IP Statement(s)
Moss Nutrition M Professional Supplements Est. 1991
KAPB is a trademark of Kaneka Corporation.
Formula
Multi-strain probiotic blend with vitamin D3
FDA Statement of Identity
Dietary Supplement
Suggested/Recommended/Usage/Directions
Suggested use: 1 capsule per day after a meal, or as directed by your healthcare professional.
Formulation
Does not contain gluten, dairy or GMOs.
Precautions
Warning: If you are taking medication, have a medical condition or an upcoming medical procedure, or are pregnant or nursing, consult a physician before using.
If adverse reactions occur, discontinue use and consult your healthcare practitioner.
Keep out of reach of children.
Storage
Store sealed in a cool, dry place.
Is this label outdated? Report a formula or label change and our pharmacy team will review it.
PB-4 Select by Moss Nutrition 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 PB-4 Select by Moss Nutrition
These are the 5 active ingredients this product is made of. Select any to open its full monograph.
Serving size1 Capsule(s) Dosage formCapsule Servings per container30 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 D3
Interacts with715 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,...
Vitamin D3 monograph & interactionsPB-4 Proprietary Probiotic Blend
- › L. plantarum KABP-022
- › L. plantarum KABP-023
- › L. Plantarum KABP-033
- › P. acidilactici KABP-21
Other (inactive) ingredients: Hydroxypropyl Methylcellulose, Maltodextrin, Vegetable Stearate. These complete the product’s ingredient list but are not active constituents.
PB-4 Select by Moss Nutrition Drug Interactions
HelloPharmacist Interaction Report
PB-4 Select by Moss Nutrition contains vitamin D3, which interacts with a substantial number of medications.
The most serious interaction is with digoxin (a heart rhythm medication): high-dose vitamin D can raise blood calcium levels (hypercalcemia), which increases the risk of dangerous heart arrhythmias when combined with digoxin. Altogether, these interactions span 716 individual medications.
Read the full breakdown — every affected drug type, severity by severity
Vitamin D3 also has moderate-severity interactions with several other heart and blood-pressure drugs — verapamil, diltiazem (both used for arrhythmias), and thiazide diuretics (water pills) — because hypercalcemia can blunt their effectiveness or worsen heart rhythm problems. It may reduce how well atorvastatin (a cholesterol drug) is absorbed, and it can theoretically increase the risk of high blood calcium if you're also using calcipotriene (a psoriasis cream).
There's also a minor concern that vitamin D might speed up how your liver processes certain medications (CYP3A4 substrates).
The other four ingredients in this product — four Lactobacillus and Pediococcus strains — could not be checked for interactions because we hold no interaction data for them. Before you start PB-4 Select, use the medication checker below to see whether any of your prescriptions overlap with vitamin D3's known interactions.
Check your own medications below · Editorial policy · How we use AI
Want to check YOUR meds against PB-4 Select?
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 PB-4 Select interact with 715 drugs. Click any drug to see the details.
1 of the 5 ingredients in PB-4 Select interact with drugs. Each result below shows which ingredient is responsible. Vitamin D3
Chlorothiazide, MethyldopaAldochlor, Aldoclor 150, Aldoclor 250
How Chlorothiazide, Methyldopa interacts with PB-4 Select — through 1 ingredient. Tap an ingredient for the detail:
Vitamin D3Thiazide Diuretics Moderate
Interaction Summary
Theoretically, taking thiazide diuretics and high-dose vitamin D can increase the risk of hypercalcemia.
Read the full Vitamin D3 + Chlorothiazide, Methyldopa interactionChlorothiazide, ReserpineDiupres
How Chlorothiazide, Reserpine interacts with PB-4 Select — through 1 ingredient. Tap an ingredient for the detail:
Vitamin D3Thiazide Diuretics Moderate
Interaction Summary
Theoretically, taking thiazide diuretics and high-dose vitamin D can increase the risk of hypercalcemia.
Read the full Vitamin D3 + Chlorothiazide, Reserpine interactionChlorthalidoneHygroton, Thalitone
How Chlorthalidone interacts with PB-4 Select — through 1 ingredient. Tap an ingredient for the detail:
Vitamin D3Thiazide Diuretics Moderate
Interaction Summary
Theoretically, taking thiazide diuretics and high-dose vitamin D can increase the risk of hypercalcemia.
Read the full Vitamin D3 + Chlorthalidone interactionChlorthalidone, ClonidineClorpres, Combipres
How Chlorthalidone, Clonidine interacts with PB-4 Select — through 1 ingredient. Tap an ingredient for the detail:
Vitamin D3Thiazide Diuretics Moderate
Interaction Summary
Theoretically, taking thiazide diuretics and high-dose vitamin D can increase the risk of hypercalcemia.
Read the full Vitamin D3 + Chlorthalidone, Clonidine interactionCryptenamine, MethyclothiazideDiutensen
How Cryptenamine, Methyclothiazide interacts with PB-4 Select — through 1 ingredient. Tap an ingredient for the detail:
Vitamin D3Thiazide Diuretics Moderate
Interaction Summary
Theoretically, taking thiazide diuretics and high-dose vitamin D can increase the risk of hypercalcemia.
Read the full Vitamin D3 + Cryptenamine, Methyclothiazide interactionCyclothiazideAnhydron, Fluidil
How Cyclothiazide interacts with PB-4 Select — through 1 ingredient. Tap an ingredient for the detail:
Vitamin D3Thiazide Diuretics Moderate
Interaction Summary
Theoretically, taking thiazide diuretics and high-dose vitamin D can increase the risk of hypercalcemia.
Read the full Vitamin D3 + Cyclothiazide interactionDeserpidine, HydrochlorothiazideOreticyl, Oreticyl Forte
How Deserpidine, Hydrochlorothiazide interacts with PB-4 Select — through 1 ingredient. Tap an ingredient for the detail:
Vitamin D3Thiazide Diuretics Moderate
Interaction Summary
Theoretically, taking thiazide diuretics and high-dose vitamin D can increase the risk of hypercalcemia.
Read the full Vitamin D3 + Deserpidine, Hydrochlorothiazide interactionDeserpidine, MethyclothiazideEnduronyl, Enduronyl Forte
How Deserpidine, Methyclothiazide interacts with PB-4 Select — through 1 ingredient. Tap an ingredient for the detail:
Vitamin D3Thiazide Diuretics Moderate
Interaction Summary
Theoretically, taking thiazide diuretics and high-dose vitamin D can increase the risk of hypercalcemia.
Read the full Vitamin D3 + Deserpidine, Methyclothiazide interactionDigoxinDigitek, Lanoxicaps, Lanoxin
How Digoxin interacts with PB-4 Select — through 1 ingredient. Tap an ingredient for the detail:
Vitamin D3Digoxin (lanoxin) Moderate
Interaction Summary
Theoretically, hypercalcemia induced by high-dose vitamin D can increase the risk of arrhythmia from digoxin.
Read the full Vitamin D3 + Digoxin interactionDihydroxyaluminum Sodium CarbonateRolaids
How Dihydroxyaluminum Sodium Carbonate interacts with PB-4 Select — through 1 ingredient. Tap an ingredient for the detail:
Vitamin D3Aluminum Moderate
Interaction Summary
Vitamin D might increase aluminum absorption and toxicity, but this has only been reported in people with renal failure.
Read the full Vitamin D3 + Dihydroxyaluminum Sodium Carbonate interactionDiltiazemAdizem-SR, Adizem-XL, Angitil SR, Angitil XL, Calcicard CR, Cardizem +23 more
How Diltiazem interacts with PB-4 Select — through 1 ingredient. Tap an ingredient for the detail:
Vitamin D3Diltiazem (cardizem, Others), Cytochrome P450 3a4 (cyp3a4) Substrates Moderate
Interaction Summary
Theoretically, hypercalcemia induced by high-dose vitamin D can reduce the therapeutic effects of diltiazem for arrhythmia.
Read the full Vitamin D3 + Diltiazem interactionDiltiazem, EnalaprilTeczem
How Diltiazem, Enalapril interacts with PB-4 Select — through 1 ingredient. Tap an ingredient for the detail:
Vitamin D3Cytochrome P450 3a4 (cyp3a4) Substrates, Diltiazem (cardizem, Others) Moderate
Interaction Summary
Vitamin D might induce CYP3A4 enzymes and reduce the bioavailability of CYP3A4 substrates.
Read the full Vitamin D3 + Diltiazem, Enalapril interactionEnalapril Maleate, HydrochlorothiazideVaseretic
How Enalapril Maleate, Hydrochlorothiazide interacts with PB-4 Select — through 1 ingredient. Tap an ingredient for the detail:
Vitamin D3Thiazide Diuretics Moderate
Interaction Summary
Theoretically, taking thiazide diuretics and high-dose vitamin D can increase the risk of hypercalcemia.
Read the full Vitamin D3 + Enalapril Maleate, Hydrochlorothiazide interactionEzetimibe, AtorvastatinLiptruzet
How Ezetimibe, Atorvastatin interacts with PB-4 Select — through 1 ingredient. Tap an ingredient for the detail:
Vitamin D3Atorvastatin (lipitor), Cytochrome P450 3a4 (cyp3a4) Substrates Moderate
Interaction Summary
Vitamin D might reduce absorption of atorvastatin.
Read the full Vitamin D3 + Ezetimibe, Atorvastatin interactionFish Oil TriglyceridesOmegaven
How Fish Oil Triglycerides interacts with PB-4 Select — through 1 ingredient. Tap an ingredient for the detail:
Vitamin D3Aluminum Moderate
Interaction Summary
Vitamin D might increase aluminum absorption and toxicity, but this has only been reported in people with renal failure.
Read the full Vitamin D3 + Fish Oil Triglycerides interactionFosinopril, HydrochlorothiazideMonopril HCT
How Fosinopril, Hydrochlorothiazide interacts with PB-4 Select — through 1 ingredient. Tap an ingredient for the detail:
Vitamin D3Thiazide Diuretics Moderate
Interaction Summary
Theoretically, taking thiazide diuretics and high-dose vitamin D can increase the risk of hypercalcemia.
Read the full Vitamin D3 + Fosinopril, Hydrochlorothiazide interactionGuanethidine, HydrochlorothiazideEsimil
How Guanethidine, Hydrochlorothiazide interacts with PB-4 Select — through 1 ingredient. Tap an ingredient for the detail:
Vitamin D3Thiazide Diuretics Moderate
Interaction Summary
Theoretically, taking thiazide diuretics and high-dose vitamin D can increase the risk of hypercalcemia.
Read the full Vitamin D3 + Guanethidine, Hydrochlorothiazide interactionHydralazine, HydrochlorothiazideApresazide, Apresoline-Esidrix
How Hydralazine, Hydrochlorothiazide interacts with PB-4 Select — through 1 ingredient. Tap an ingredient for the detail:
Vitamin D3Thiazide Diuretics Moderate
Interaction Summary
Theoretically, taking thiazide diuretics and high-dose vitamin D can increase the risk of hypercalcemia.
Read the full Vitamin D3 + Hydralazine, Hydrochlorothiazide interactionHydralazine, Hydrochlorothiazide, ReserpineSer-Ap-Es, Unipres, Uniserp
How Hydralazine, Hydrochlorothiazide, Reserpine interacts with PB-4 Select — through 1 ingredient. Tap an ingredient for the detail:
Vitamin D3Thiazide Diuretics Moderate
Interaction Summary
Theoretically, taking thiazide diuretics and high-dose vitamin D can increase the risk of hypercalcemia.
Read the full Vitamin D3 + Hydralazine, Hydrochlorothiazide, Reserpine interactionHydrochlorothiazideAquazide, Aquazide H, Esidrix, HCTZ, Hydro, Hydro-D +3 more
How Hydrochlorothiazide interacts with PB-4 Select — through 1 ingredient. Tap an ingredient for the detail:
Vitamin D3Thiazide Diuretics Moderate
Interaction Summary
Theoretically, taking thiazide diuretics and high-dose vitamin D can increase the risk of hypercalcemia.
Read the full Vitamin D3 + Hydrochlorothiazide interactionHydrochlorothiazide, IrbesartanAvalide
How Hydrochlorothiazide, Irbesartan interacts with PB-4 Select — through 1 ingredient. Tap an ingredient for the detail:
Vitamin D3Thiazide Diuretics Moderate
Interaction Summary
Theoretically, taking thiazide diuretics and high-dose vitamin D can increase the risk of hypercalcemia.
Read the full Vitamin D3 + Hydrochlorothiazide, Irbesartan interactionHydrochlorothiazide, LabetalolTrandate HCT
How Hydrochlorothiazide, Labetalol interacts with PB-4 Select — through 1 ingredient. Tap an ingredient for the detail:
Vitamin D3Thiazide Diuretics Moderate
Interaction Summary
Theoretically, taking thiazide diuretics and high-dose vitamin D can increase the risk of hypercalcemia.
Read the full Vitamin D3 + Hydrochlorothiazide, Labetalol interactionHydrochlorothiazide, LisinoprilPrinzide, Zestoretic
How Hydrochlorothiazide, Lisinopril interacts with PB-4 Select — through 1 ingredient. Tap an ingredient for the detail:
Vitamin D3Thiazide Diuretics Moderate
Interaction Summary
Theoretically, taking thiazide diuretics and high-dose vitamin D can increase the risk of hypercalcemia.
Read the full Vitamin D3 + Hydrochlorothiazide, Lisinopril interactionHydrochlorothiazide, Losartan PotassiumHyzaar
How Hydrochlorothiazide, Losartan Potassium interacts with PB-4 Select — through 1 ingredient. Tap an ingredient for the detail:
Vitamin D3Thiazide Diuretics, Cytochrome P450 3a4 (cyp3a4) Substrates Moderate
Interaction Summary
Theoretically, taking thiazide diuretics and high-dose vitamin D can increase the risk of hypercalcemia.
Read the full Vitamin D3 + Hydrochlorothiazide, Losartan Potassium interactionHydrochlorothiazide, MethyldopaAldoril 15, Aldoril 25, Aldoril D30, Methazide
How Hydrochlorothiazide, Methyldopa interacts with PB-4 Select — through 1 ingredient. Tap an ingredient for the detail:
Vitamin D3Thiazide Diuretics Moderate
Interaction Summary
Theoretically, taking thiazide diuretics and high-dose vitamin D can increase the risk of hypercalcemia.
Read the full Vitamin D3 + Hydrochlorothiazide, Methyldopa interactionHydrochlorothiazide, MetoprololLopressor HCT
How Hydrochlorothiazide, Metoprolol interacts with PB-4 Select — through 1 ingredient. Tap an ingredient for the detail:
Vitamin D3Thiazide Diuretics Moderate
Interaction Summary
Theoretically, taking thiazide diuretics and high-dose vitamin D can increase the risk of hypercalcemia.
Read the full Vitamin D3 + Hydrochlorothiazide, Metoprolol interactionHydrochlorothiazide, MoexiprilUniretic
How Hydrochlorothiazide, Moexipril interacts with PB-4 Select — through 1 ingredient. Tap an ingredient for the detail:
Vitamin D3Thiazide Diuretics Moderate
Interaction Summary
Theoretically, taking thiazide diuretics and high-dose vitamin D can increase the risk of hypercalcemia.
Read the full Vitamin D3 + Hydrochlorothiazide, Moexipril interactionHydrochlorothiazide, PindololViskazide
How Hydrochlorothiazide, Pindolol interacts with PB-4 Select — through 1 ingredient. Tap an ingredient for the detail:
Vitamin D3Thiazide Diuretics Moderate
Interaction Summary
Theoretically, taking thiazide diuretics and high-dose vitamin D can increase the risk of hypercalcemia.
Read the full Vitamin D3 + Hydrochlorothiazide, Pindolol interactionHydrochlorothiazide, PropranololInderide
How Hydrochlorothiazide, Propranolol interacts with PB-4 Select — through 1 ingredient. Tap an ingredient for the detail:
Vitamin D3Thiazide Diuretics Moderate
Interaction Summary
Theoretically, taking thiazide diuretics and high-dose vitamin D can increase the risk of hypercalcemia.
Read the full Vitamin D3 + Hydrochlorothiazide, Propranolol interactionHydrochlorothiazide, QuinaprilAccuretic
How Hydrochlorothiazide, Quinapril interacts with PB-4 Select — through 1 ingredient. Tap an ingredient for the detail:
Vitamin D3Thiazide Diuretics Moderate
Interaction Summary
Theoretically, taking thiazide diuretics and high-dose vitamin D can increase the risk of hypercalcemia.
Read the full Vitamin D3 + Hydrochlorothiazide, Quinapril interactionEach ingredient & the kinds of drugs it affects
For each ingredient in PB-4 Select with known interactions, here are the types of medications it can affect. Open any type for the detail — or search your exact drug in the checker above.
Vitamin D3
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.
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.
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.
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.
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.
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.
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.
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.
Brand information
Manufacturer and brand details for PB-4 Select, from the product label.
Moss Nutrition
See all Moss Nutrition products- Name
- Moss Nutrition Products, Inc.
- Street Address
- 380 Russell Street
- City
- Hadley
- State
- MA
- ZipCode
- 01035
- Phone Number
- 800-851-5444
- Web Address
- www.mossnutrition.com
PB-4 Select by Moss Nutrition: Common Questions
Does PB-4 Select by Moss Nutrition interact with any medications?
How can one product interact with so many drugs?
Where does this information come from?
Is vitamin D3 safe to take during pregnancy?
Can I take vitamin D3 if I'm breastfeeding?
What happens if I take too much vitamin D3?
What are the probiotic strains in this product for?
Does this product have fillers?
Written and reviewed by the HelloPharmacist editorial staff. Our editorial policy
Not sure if PB-4 Select 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 PB-4 Select’s Ingredients
Every ingredient we hold a full HelloPharmacist monograph for — uses, evidence, safety, and the complete interaction list.
Sources & How We Checked
PB-4 Select'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 26 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 D 26 references
- McEvoy GK, ed. AHFS Drug Information. Bethesda, MD: American Society of Health-System Pharmacists, 1998.
- Tatro DS, ed. Drug Interactions Facts. Facts and Comparisons Inc., St. Louis, MO. 1999.
- Koutkia P, Chen TC, Holick MF. Vitamin D intoxication associated with an over-the-counter supplement. N Engl J Med 2001;345:66-7. PubMed
- Bar-Or D, Yoel G. Calcium and calciferol antagonize effect of verapamil in atrial fibrillation. Br Med J 1981;282:1585-6.
- Demontis R, Leflon A, Fournier A, et al. 1 alpha(OH) vitamin D3 increases plasma aluminum in hemodialyzed patients taking AI(OH)3. Clin Nephrol 1986;26:146-9.
- Crowe M, Wollner L, Griffiths RA. Hypercalcemia following vitamin D and thiazide therapy in the elderly. Practitioner 1984;228:312-3.
- Parfitt AM. Thiazide-induced hypercalcemia in vitamin D-treated hypoparathyroidism. Ann Intern Med 1972;77:557-63. PubMed
- Thiazide diuretics and the risk of osteoporosis. Pharmacist's Letter/Prescriber's Letter 2003;19(11):191105.
- Moon J. The role of vitamin D in toxic metal absorption. J Am Coll Nutr 1994;13:559-64.
- Demontis R, Reissi D, Noel C, et al. Indirect clinical evidence that 1alphaOH vitamin D<SUB>3</SUB> increases the intestinal absorption of aluminum. Clin Nephrol 1989;31:123-7.
- Adler AJ, Berlyne GM. Duodenal aluminum absorption in the rat: effect of vitamin D. Am J Physiol 1985;249:G209-13. PubMed
- Schwartz JB. Effects of vitamin D supplementation in atorvastatin-treated patients: A new drug interaction with an unexpected consequence. Clin Pharmacol Ther 2009;85:198-203. PubMed
- 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
- Cox KA, Dunn MA. Aluminum toxicity alters the regulation of calbindin-D28k protein and mRNA expression in chick intestine. J Nutr 2001;131:2007-13. PubMed
- Escribano, J., Balaguer, A., Pagone, F., Feliu, A., and Roque, I. Figuls. Pharmacological interventions for preventing complications in idiopathic hypercalciuria. Cochrane.Database.Syst.Rev. 2009;(1):CD004754. PubMed
- Carlton, S., Clopton, D., and Cappuzzo, K. A. Vitamin D deficiency: appropriate replenishment therapies and the effects of vitamin D toxicity. Consult Pharm 2010;25(3):171-177. PubMed
- Wang, H., Xia, N., Yang, Y., and Peng, D. Q. Influence of vitamin D supplementation on plasma lipid profiles: a meta-analysis of randomized controlled trials. Lipids Health Dis. 2012;11:42. PubMed
- Turner AN, Carr Reese P, Fields KS, Anderson J, Ervin M, Davis JA, Fichorova RN, Roberts MW, Klebanoff MA, Jackson RD. A blinded, randomized controlled trial of high-dose vitamin D supplementation to reduce recurrence of bacterial vaginosis. Am J Obstet G PubMed
- Weiner M, Epstein FH. Signs and symptoms of electrolyte disorders. Yale J Biol Med. 1970;43(2):76-109.
- 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
- Roth DE, Leung M, Mesfin E, Qamar H, Watterworth J, Papp E. Vitamin D supplementation during pregnancy: state of the evidence from a systematic review of randomised trials. BMJ. 2017;359:j5237. PubMed
- Murai IH, Fernandes AL, Sales LP, et al. Effect of a single high dose of vitamin D3 on hospital length of stay in patients with moderate to severe COVID-19: A randomized clinical trial. JAMA. 2021.
- Wang Z, Schuetz EG, Xu Y, Thummel KE. Interplay between vitamin D and the drug metabolizing enzyme CYP3A4. J Steroid Biochem Mol Biol 2013;136:54-8. PubMed
- Doyle D, Browne U, Brickley A, Murphy D. Vitamin D-induced hypercalcaemia and acute kidney injury in sarcoidosis. BMJ Case Rep 2023;16(1):e250580. PubMed
- Williamson A, Martineau AR, Sheikh A, Jolliffe D, Griffiths CJ. Vitamin D for the management of asthma. Cochrane Database Syst Rev 2023;2(2):CD011511. PubMed
- Kinesya E, Santoso D, Gde Arya N, et al. Vitamin D as adjuvant therapy for diabetic foot ulcers: Systematic review and meta-analysis approach. Clin Nutr ESPEN 2023;54:137-143. PubMed
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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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