Oat Fiber Plus Ingredients & Drug Interactions
by NOW
What is this page for?
First and foremost: checking Oat Fiber Plus 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
Oat Fiber Plus is a dietary supplement by NOW with 4 active ingredients. Its ingredients are commonly taken for constipation, diarrhea, high cholesterol.Based on those ingredients, 2,031 medications have a known interaction with it, the most serious rated moderate. The ingredients most likely to interact are Dietary Fiber, Apple Pectin powder. Use the checker below to test your specific medication, or read the full HelloPharmacist Interaction Report.
Check Your Meds Against Oat Fiber Plus by NOW
Ask about any prescription or over-the-counter medication and we check it for interactions with Oat Fiber Plus by NOW — 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 Oat Fiber Plus by NOW
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
Oat Fiber Plus has 3 active ingredients: apple pectin powder, brown rice bran, and oat fiber. Pectin is a soluble fiber that comes from fruit; brown rice bran is the outer layer of rice grain, also a fiber source.
These work as dietary fibers to support digestive health. The tablet also contains inactive ingredients (cellulose, stearic acid, croscarmellose sodium, and silica) that help hold it together.
Does it work?
Strong evidence
Apple pectin is possibly effective for high cholesterol (hypercholesterolemia). The evidence for its use in prediabetes is insufficient — we don't have enough reliable data to say whether it helps.
Brown rice bran is possibly effective for dyslipidemia (abnormal blood lipid levels) but appears possibly ineffective for colorectal cancer prevention. For alopecia areata (patchy hair loss), the evidence on brown rice bran is insufficient.
Oat fiber's effectiveness for any condition is not established in the data we hold.
How safe is it?
Well-documented data
Pectin from food and typical supplement amounts is generally well tolerated. The most common side effects are diarrhea, gas, loose stools, and mild cramps.
Rarely, sensitive people may have allergic reactions, including severe ones (anaphylaxis). Brown rice bran is also generally well tolerated, though increasing bran intake can cause temporary belly discomfort, gas, and irregular bowel habits; rare allergic reactions are possible.
Both ingredients may not be as well studied at high supplement doses in pregnancy or while breastfeeding — talk with your doctor or pharmacist if you're pregnant, planning pregnancy, or nursing.
Meds to double-check
Moderate interaction found
Double-check before taking this product if you use digoxin (a heart rhythm medication) — pectin may reduce how much of it you absorb. Also check if you take lovastatin or other cholesterol-lowering statins, or tetracycline antibiotics like doxycycline — pectin may decrease their absorption.
No interactions are documented for oat fiber, but we cannot check it.
The bottom line
Scorecard at a glanceFully disclosed formula with clinical evidence supporting its stated purpose. Moderate medication interactions have been identified, and safety information is well characterized.
This product may help with cholesterol or lipid levels, though the evidence is moderate. If you take heart medications like digoxin, cholesterol drugs like lovastatin, or tetracycline antibiotics, check with your doctor or pharmacist before starting — pectin can interfere with how your body absorbs these.
Most people tolerate it well, but gas and loose stools are common when you first increase fiber intake. Talk it over with your own healthcare provider, especially if you're on prescription medications.
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 May 23, 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 Oat Fiber Plus, straight from the product label.
| Brand | NOW |
|---|---|
| Barcode (UPC) | 733739059642 |
| Net contents | 100 Tablet(s) |
| Market status | On market |
| Date entered into DSLD | May 23, 2014 |
| DSLD ID | 33518 |
| Product type | Fiber And Other Nutrients |
| Supplement form | Tablet Or Pill |
| Dietary claims / uses | Nutrient, All Other |
| Intended target group(s) | Adult (18 - 50 Years), 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 Oat Fiber Plus by NOW, sourced from the NIH Dietary Supplement Label Database.
Supplement Facts
| Ingredient | Amount | % DV |
|---|---|---|
| Total Carbohydrates | 2 Gram(s) | 1% |
| Dietary Fiber | 1 Gram(s) | 4% |
| Apple Pectin powder | 165 mg | -- |
| Brown Rice Bran | 165 mg | -- |
| Oat Fiber | 1.65 Gram(s) | -- |
Other ingredients: Cellulose, Stearic Acid, Croscarmellose Sodium, Silica
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.
Suggested/Recommended/Usage/Directions
SUGGESTED USAGE: As a dietary supplement, take 3 tablets twice daily, with a large glass of water or juice.
General Statements
Because many people often fail to obtain adequate fiber in their diets, Oat Fiber, in the form of a tablet, may help to alleviate such dietary shortcomings. The combination of fiber from oats, brown rice and apple pectin is especially useful in balancing fiber intake.
Please Recycle. TABLET SIZE Made in the USA
NUTRITIONAL HEALTH
with Brown Rice Bran & Apple Pectin
For more product information visit www.nowfoods.com/5964
Precautions
Caution: For adults only.
Do not use this product if pregnant/nursing, taking medication, or have a medical condition.
Keep out of reach of children.
Not manufactured with wheat, soy, milk, egg, fish, shellfish or tree nut ingredients. Produced in a GMP facility that processes other ingredients containing these allergens.
Storage
Store in a cool, dry place after opening.
FDA Statement of Identity
A Dietary Supplement
Formulation
Vegetarian/Vegan
Not manufactured with wheat, soy, milk, egg, fish, shellfish or tree nut ingredients.
Seals/Symbols
QUALITY GMP ASSURED
General
CODE 5964B V2
Is this label outdated? Report a formula or label change and our pharmacy team will review it.
Oat Fiber Plus by NOW 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 Oat Fiber Plus by NOW
These are the 4 active ingredients this product is made of. Select any to open its full monograph.
Serving size3 Tablet(s) Dosage formTablet Or Pill Servings per container33 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.
Dietary Fiber
Interacts with2,025 drugs
Black psyllium is a soluble-fiber supplement made from the seeds of a Plantago plant, used mostly to ease constipation and support digestive health. I...
Dietary Fiber monograph & interactionsApple Pectin powder
Interacts with23 drugs
Pectin is a natural soluble fiber found in fruits like apples and citrus, and it is widely used in foods and as a fiber supplement. It may modestly he...
Apple Pectin powder monograph & interactionsBrown Rice Bran
No knowninteractions
Rice bran is the nutrient-rich outer layer of the rice grain and is a good source of fiber, healthy fats, and plant compounds. It is most studied for...
Brown Rice Bran monograph & interactionsOat Fiber
Other (inactive) ingredients: Cellulose, Stearic Acid, Croscarmellose Sodium, Silica. These complete the product’s ingredient list but are not active constituents.
Oat Fiber Plus by NOW Drug Interactions
HelloPharmacist Interaction Report
Oat Fiber Plus by NOW contains apple pectin powder and brown rice bran.
Apple pectin has documented interactions with several medication types. The most serious concern is with digoxin (Lanoxin, a heart medication) — pectin may reduce how much digoxin your body absorbs, potentially weakening its effect on your heart rhythm.
Read the full breakdown — every affected drug type, severity by severity
Pectin also interacts with lovastatin (a cholesterol drug) and tetracycline antibiotics (used to treat infections). Both are Moderate-severity interactions: pectin may lower how much of these medications reaches your bloodstream, which could reduce how well they work.
Brown rice bran, the other active ingredient we could check, has no interactions documented in our data.
We do not hold interaction data for oat fiber, so we cannot assess whether it affects any medications. Altogether, these interactions span 23 individual medications.
Before you start this product, run your exact prescriptions through the checker below — especially if you take heart, cholesterol, or antibiotic medications.
Check your own medications below · Editorial policy · How we use AI
Want to check YOUR meds against Oat Fiber Plus?
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 Oat Fiber Plus interact with 2,031 drugs. Click any drug to see the details.
2 of the 4 ingredients in Oat Fiber Plus interact with drugs. Each result below shows which ingredient is responsible. Dietary Fiber Apple Pectin powder
Alogliptin, MetforminKazano
How Alogliptin, Metformin interacts with Oat Fiber Plus — through 1 ingredient. Tap an ingredient for the detail:
Dietary FiberOral Drugs, Metformin (glucophage) Moderate
Interaction Summary
Theoretically, psyllium might increase, decrease, or have no effect on the absorption of oral drugs.
Read the full Dietary Fiber + Alogliptin, Metformin interactionAmphotericin, TetracyclineMysteclin-F
How Amphotericin, Tetracycline interacts with Oat Fiber Plus — through 2 ingredients. Tap an ingredient for the detail:
Apple Pectin PowderTetracycline Antibiotics Moderate
Interaction Summary
Theoretically, pectin might reduce the absorption of tetracycline antibiotics, potentially decreasing their effectiveness.
Read the full Apple Pectin Powder + Amphotericin, Tetracycline interactionDietary FiberOral Drugs Minor
Interaction Summary
Theoretically, psyllium might increase, decrease, or have no effect on the absorption of oral drugs.
Read the full Dietary Fiber + Amphotericin, Tetracycline interactionBismuth Subsalicylate, Metronidazole, TetracyclineHelidac
How Bismuth Subsalicylate, Metronidazole, Tetracycline interacts with Oat Fiber Plus — through 2 ingredients. Tap an ingredient for the detail:
Apple Pectin PowderTetracycline Antibiotics Moderate
Interaction Summary
Theoretically, pectin might reduce the absorption of tetracycline antibiotics, potentially decreasing their effectiveness.
Read the full Apple Pectin Powder + Bismuth Subsalicylate, Metronidazole, Tetracycline interactionDietary FiberOral Drugs Minor
Interaction Summary
Theoretically, psyllium might increase, decrease, or have no effect on the absorption of oral drugs.
Read the full Dietary Fiber + Bismuth Subsalicylate, Metronidazole, Tetracycline interactionCanagliflozin, MetforminInvokamet
How Canagliflozin, Metformin interacts with Oat Fiber Plus — through 1 ingredient. Tap an ingredient for the detail:
Dietary FiberOral Drugs, Metformin (glucophage) Moderate
Interaction Summary
Theoretically, psyllium might increase, decrease, or have no effect on the absorption of oral drugs.
Read the full Dietary Fiber + Canagliflozin, Metformin interactionCanagliflozin, Metformin HydrochlorideInvokamet XR
How Canagliflozin, Metformin Hydrochloride interacts with Oat Fiber Plus — through 1 ingredient. Tap an ingredient for the detail:
Dietary FiberMetformin (glucophage), Oral Drugs Moderate
Interaction Summary
Theoretically, black psyllium might increase the therapeutic and adverse effects of metformin.
Read the full Dietary Fiber + Canagliflozin, Metformin Hydrochloride interactionCarbamazepineCarbatrol, Carnexiv, Equetro, Tegretol, Tegretol XR
How Carbamazepine interacts with Oat Fiber Plus — through 1 ingredient. Tap an ingredient for the detail:
Dietary FiberOral Drugs, Carbamazepine (tegretol) Moderate
Interaction Summary
Theoretically, psyllium might increase, decrease, or have no effect on the absorption of oral drugs.
Read the full Dietary Fiber + Carbamazepine interactionChlortetracyclineAureomycin
How Chlortetracycline interacts with Oat Fiber Plus — through 2 ingredients. Tap an ingredient for the detail:
Apple Pectin PowderTetracycline Antibiotics Moderate
Interaction Summary
Theoretically, pectin might reduce the absorption of tetracycline antibiotics, potentially decreasing their effectiveness.
Read the full Apple Pectin Powder + Chlortetracycline interactionDietary FiberOral Drugs Minor
Interaction Summary
Theoretically, psyllium might increase, decrease, or have no effect on the absorption of oral drugs.
Read the full Dietary Fiber + Chlortetracycline interactionDapagliflozin Propanediol, MetforminXigduo XR
How Dapagliflozin Propanediol, Metformin interacts with Oat Fiber Plus — through 1 ingredient. Tap an ingredient for the detail:
Dietary FiberOral Drugs, Metformin (glucophage) Moderate
Interaction Summary
Theoretically, psyllium might increase, decrease, or have no effect on the absorption of oral drugs.
Read the full Dietary Fiber + Dapagliflozin Propanediol, Metformin interactionDapagliflozin, Metformin Hydrochloride, Saxagliptin HydrochlorideQternmet XR
How Dapagliflozin, Metformin Hydrochloride, Saxagliptin Hydrochloride interacts with Oat Fiber Plus — through 1 ingredient. Tap an ingredient for the detail:
Dietary FiberOral Drugs, Metformin (glucophage) Moderate
Interaction Summary
Theoretically, psyllium might increase, decrease, or have no effect on the absorption of oral drugs.
Read the full Dietary Fiber + Dapagliflozin, Metformin Hydrochloride, Saxagliptin Hydrochloride interactionDemeclocyclineDeclomycin
How Demeclocycline interacts with Oat Fiber Plus — through 2 ingredients. Tap an ingredient for the detail:
Apple Pectin PowderTetracycline Antibiotics Moderate
Interaction Summary
Theoretically, pectin might reduce the absorption of tetracycline antibiotics, potentially decreasing their effectiveness.
Read the full Apple Pectin Powder + Demeclocycline interactionDietary FiberOral Drugs Minor
Interaction Summary
Theoretically, psyllium might increase, decrease, or have no effect on the absorption of oral drugs.
Read the full Dietary Fiber + Demeclocycline interactionDigoxinDigitek, Lanoxicaps, Lanoxin
How Digoxin interacts with Oat Fiber Plus — through 2 ingredients. Tap an ingredient for the detail:
Apple Pectin PowderDigoxin (lanoxin) Moderate
Interaction Summary
Theoretically, pectin might reduce the absorption of digoxin, potentially decreasing its effectiveness.
Read the full Apple Pectin Powder + Digoxin interactionDietary FiberOral Drugs, Digoxin (lanoxin) Minor
Interaction Summary
Theoretically, psyllium might increase, decrease, or have no effect on the absorption of oral drugs.
Read the full Dietary Fiber + Digoxin interactionDoripenemDoribax
How Doripenem interacts with Oat Fiber Plus — through 1 ingredient. Tap an ingredient for the detail:
Apple Pectin PowderTetracycline Antibiotics Moderate
Interaction Summary
Theoretically, pectin might reduce the absorption of tetracycline antibiotics, potentially decreasing their effectiveness.
Read the full Apple Pectin Powder + Doripenem interactionDoxycyclineDoryx, Doxy, Doxy-D, Doxycin, Doxycycline Injection, Doxylin +6 more
How Doxycycline interacts with Oat Fiber Plus — through 2 ingredients. Tap an ingredient for the detail:
Apple Pectin PowderTetracycline Antibiotics Moderate
Interaction Summary
Theoretically, pectin might reduce the absorption of tetracycline antibiotics, potentially decreasing their effectiveness.
Read the full Apple Pectin Powder + Doxycycline interactionDietary FiberOral Drugs Minor
Interaction Summary
Theoretically, psyllium might increase, decrease, or have no effect on the absorption of oral drugs.
Read the full Dietary Fiber + Doxycycline interactionDoxycycline HyclateActiclate, Acticlate Cap, Lymepak
How Doxycycline Hyclate interacts with Oat Fiber Plus — through 2 ingredients. Tap an ingredient for the detail:
Apple Pectin PowderTetracycline Antibiotics Moderate
Interaction Summary
Theoretically, pectin might reduce the absorption of tetracycline antibiotics, potentially decreasing their effectiveness.
Read the full Apple Pectin Powder + Doxycycline Hyclate interactionDietary FiberOral Drugs Minor
Interaction Summary
Theoretically, psyllium might increase, decrease, or have no effect on the absorption of oral drugs.
Read the full Dietary Fiber + Doxycycline Hyclate interactionDoxycycline MonohydrateErfacea
How Doxycycline Monohydrate interacts with Oat Fiber Plus — through 2 ingredients. Tap an ingredient for the detail:
Apple Pectin PowderTetracycline Antibiotics Moderate
Interaction Summary
Theoretically, pectin might reduce the absorption of tetracycline antibiotics, potentially decreasing their effectiveness.
Read the full Apple Pectin Powder + Doxycycline Monohydrate interactionDietary FiberOral Drugs Minor
Interaction Summary
Theoretically, psyllium might increase, decrease, or have no effect on the absorption of oral drugs.
Read the full Dietary Fiber + Doxycycline Monohydrate interactionDoxycylineDoxychel
How Doxycyline interacts with Oat Fiber Plus — through 1 ingredient. Tap an ingredient for the detail:
Apple Pectin PowderTetracycline Antibiotics Moderate
Interaction Summary
Theoretically, pectin might reduce the absorption of tetracycline antibiotics, potentially decreasing their effectiveness.
Read the full Apple Pectin Powder + Doxycyline interactionEmpagliflozin, Linagliptin, Metformin HydrochlorideTrijardy XR
How Empagliflozin, Linagliptin, Metformin Hydrochloride interacts with Oat Fiber Plus — through 1 ingredient. Tap an ingredient for the detail:
Dietary FiberMetformin (glucophage), Oral Drugs Moderate
Interaction Summary
Theoretically, black psyllium might increase the therapeutic and adverse effects of metformin.
Read the full Dietary Fiber + Empagliflozin, Linagliptin, Metformin Hydrochloride interactionEmpagliflozin, MetforminSynjardy
How Empagliflozin, Metformin interacts with Oat Fiber Plus — through 1 ingredient. Tap an ingredient for the detail:
Dietary FiberOral Drugs, Metformin (glucophage) Moderate
Interaction Summary
Theoretically, psyllium might increase, decrease, or have no effect on the absorption of oral drugs.
Read the full Dietary Fiber + Empagliflozin, Metformin interactionEmpagliflozin, Metformin HydrochlorideSynjardy XR
How Empagliflozin, Metformin Hydrochloride interacts with Oat Fiber Plus — through 1 ingredient. Tap an ingredient for the detail:
Dietary FiberMetformin (glucophage), Oral Drugs Moderate
Interaction Summary
Theoretically, black psyllium might increase the therapeutic and adverse effects of metformin.
Read the full Dietary Fiber + Empagliflozin, Metformin Hydrochloride interactionEravacyclineXerava
How Eravacycline interacts with Oat Fiber Plus — through 1 ingredient. Tap an ingredient for the detail:
Apple Pectin PowderTetracycline Antibiotics Moderate
Interaction Summary
Theoretically, pectin might reduce the absorption of tetracycline antibiotics, potentially decreasing their effectiveness.
Read the full Apple Pectin Powder + Eravacycline interactionErtugliflozin, Metformin HydrochlorideSegluromet
How Ertugliflozin, Metformin Hydrochloride interacts with Oat Fiber Plus — through 1 ingredient. Tap an ingredient for the detail:
Dietary FiberOral Drugs, Metformin (glucophage) Moderate
Interaction Summary
Theoretically, psyllium might increase, decrease, or have no effect on the absorption of oral drugs.
Read the full Dietary Fiber + Ertugliflozin, Metformin Hydrochloride interactionGlipizide, MetforminMetaglip
How Glipizide, Metformin interacts with Oat Fiber Plus — through 1 ingredient. Tap an ingredient for the detail:
Dietary FiberOral Drugs, Metformin (glucophage) Moderate
Interaction Summary
Theoretically, psyllium might increase, decrease, or have no effect on the absorption of oral drugs.
Read the full Dietary Fiber + Glipizide, Metformin interactionGlyburide, MetforminGlucovance
How Glyburide, Metformin interacts with Oat Fiber Plus — through 1 ingredient. Tap an ingredient for the detail:
Dietary FiberOral Drugs, Metformin (glucophage) Moderate
Interaction Summary
Theoretically, psyllium might increase, decrease, or have no effect on the absorption of oral drugs.
Read the full Dietary Fiber + Glyburide, Metformin interactionLinagliptin, Metformin HydrochlorideJentadueto XR
How Linagliptin, Metformin Hydrochloride interacts with Oat Fiber Plus — through 1 ingredient. Tap an ingredient for the detail:
Dietary FiberOral Drugs, Metformin (glucophage) Moderate
Interaction Summary
Theoretically, psyllium might increase, decrease, or have no effect on the absorption of oral drugs.
Read the full Dietary Fiber + Linagliptin, Metformin Hydrochloride interactionLithium Carbonate (prescription Drug)Eskalith, Lithium Carbonate
How Lithium Carbonate (prescription Drug) interacts with Oat Fiber Plus — through 1 ingredient. Tap an ingredient for the detail:
Dietary FiberOral Drugs, Lithium Moderate
Interaction Summary
Theoretically, psyllium might increase, decrease, or have no effect on the absorption of oral drugs.
Read the full Dietary Fiber + Lithium Carbonate (prescription Drug) interactionLovastatinAltocor, Mevacor
How Lovastatin interacts with Oat Fiber Plus — through 2 ingredients. Tap an ingredient for the detail:
Apple Pectin PowderLovastatin (mevacor) Moderate
Interaction Summary
Theoretically, pectin might reduce the absorption of lovastatin, potentially decreasing its effectiveness.
Read the full Apple Pectin Powder + Lovastatin interactionDietary FiberOral Drugs Minor
Interaction Summary
Theoretically, psyllium might increase, decrease, or have no effect on the absorption of oral drugs.
Read the full Dietary Fiber + Lovastatin interactionMetforminGlucophage, Metformin
How Metformin interacts with Oat Fiber Plus — through 1 ingredient. Tap an ingredient for the detail:
Dietary FiberMetformin (glucophage), Oral Drugs Moderate
Interaction Summary
Theoretically, black psyllium might increase the therapeutic and adverse effects of metformin.
Read the full Dietary Fiber + Metformin interactionMetformin HydrochlorideRiomet ER
How Metformin Hydrochloride interacts with Oat Fiber Plus — through 1 ingredient. Tap an ingredient for the detail:
Dietary FiberMetformin (glucophage), Oral Drugs Moderate
Interaction Summary
Theoretically, black psyllium might increase the therapeutic and adverse effects of metformin.
Read the full Dietary Fiber + Metformin Hydrochloride interactionMetformin, LinagliptinJentadueto
How Metformin, Linagliptin interacts with Oat Fiber Plus — through 1 ingredient. Tap an ingredient for the detail:
Dietary FiberOral Drugs, Metformin (glucophage) Moderate
Interaction Summary
Theoretically, psyllium might increase, decrease, or have no effect on the absorption of oral drugs.
Read the full Dietary Fiber + Metformin, Linagliptin interactionMetformin, RosiglitazoneAvandamet
How Metformin, Rosiglitazone interacts with Oat Fiber Plus — through 1 ingredient. Tap an ingredient for the detail:
Dietary FiberMetformin (glucophage), Oral Drugs Moderate
Interaction Summary
Theoretically, black psyllium might increase the therapeutic and adverse effects of metformin.
Read the full Dietary Fiber + Metformin, Rosiglitazone interactionEach ingredient & the kinds of drugs it affects
For each ingredient in Oat Fiber Plus 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.
Dietary Fiber
Carbamazepine (Tegretol)
Theoretically, black psyllium might reduce the effects of carbamazepine and increase the risk for convulsions.
Theoretically, black psyllium might reduce carbamazepine absorption. A preliminary study using blond psyllium reported decreased carbamazepine bioavailability due to binding of the drug to psyllium, as well as reduction of available fluid in the gut for dissolution of the drug. This interaction may also occur with black psyllium.
Lithium
Theoretically, taking black psyllium at the same time as lithium might reduce lithium absorption.
The fiber in black psyllium might reduce lithium absorption and plasma levels. Some case reports describe a reduction in plasma lithium levels with concomitant administration of blond psyllium. This was reversed when psyllium was stopped. This interaction may also occur with black psyllium.
Metformin (Glucophage)
Theoretically, black psyllium might increase the therapeutic and adverse effects of metformin.
Animal research shows that concurrent consumption of blond psyllium with metformin slows and increases the absorption of metformin. This interaction may also occur with black psyllium. To avoid changes in absorption, take psyllium 30-60 minutes after metformin.
Olanzapine (Zyprexa)
Theoretically, taking black psyllium at the same time as olanzapine might reduce olanzapine absorption.
The fiber in black psyllium might decrease the absorption of olanzapine. A single case report describes a reduction in the effectiveness of olanzapine when it was concomitantly administered with an unspecified type of psyllium 3 grams orally twice daily. This effect was reversed when psyllium was stopped.
Digoxin (Lanoxin)
Theoretically, taking black psyllium at the same time as digoxin might reduce digoxin absorption and decrease digoxin levels.
Psyllium might bind digoxin in the gut. However, some clinical evidence suggests that psyllium does not impact digoxin absorption.
Ethinyl Estradiol
Theoretically, taking black psyllium at the same time as ethinyl estradiol might alter levels of estradiol.
Concurrent use of blond psyllium with ethinyl estradiol results in a slight increase in the extent of ethinyl estradiol absorption and a slower rate of absorption. This is unlikely to be clinically significant.
Oral Drugs
Theoretically, psyllium might increase, decrease, or have no effect on the absorption of oral drugs.
Psyllium seems to have variable effects on drug absorption. To avoid changes in absorption, take psyllium 30-60 minutes after oral medications. Animal research shows that blond psyllium delays and increases the absorption of metformin and ethinyl estradiol. Case reports and animal research suggest that blond psyllium might reduce absorption of lithium, digoxin, olanzapine, and carbamazepine. Finally, some pharmacokinetic studies show that psyllium does not affect the absorption of levothyroxine or warfarin. Although many of these studies evaluated blond psyllium, the fiber content in black psyllium may have similar effects.
Apple Pectin powder
Digoxin (Lanoxin)
Theoretically, pectin might reduce the absorption of digoxin, potentially decreasing its effectiveness.
A small clinical study shows that taking digoxin with a kaolin-pectin suspension reduces the absorption of digoxin by about 62%. It is unclear if these effects are due to pectin, kaolin, or the combination.
Lovastatin (Mevacor)
Theoretically, pectin might reduce the absorption of lovastatin, potentially decreasing its effectiveness.
Case reports suggest that concomitant use of pectin and lovastatin might reduce the cholesterol-lowering effect of lovastatin, possibly due to reduced intestinal absorption of lovastatin.
Tetracycline Antibiotics
Theoretically, pectin might reduce the absorption of tetracycline antibiotics, potentially decreasing their effectiveness.
A small clinical study shows that taking tetracycline with bismuth subsalicylate in a kaolin-pectin suspension reduces the absorption of tetracycline by about 34%. It is unclear if these effects are due to pectin, kaolin, bismuth subsalicylate, or the combination.
Brand information
Manufacturer and brand details for Oat Fiber Plus, from the product label.
NOW
See all NOW products- Name
- NOW Foods
- Street Address
- 395 S. Glen Ellyn Rd.
- City
- Bloomingdale
- State
- IL
- ZipCode
- 60108
- Web Address
- www.nowfoods.com
Oat Fiber Plus by NOW: Common Questions
Does Oat Fiber Plus by NOW interact with any medications?
How can one product interact with so many drugs?
Where does this information come from?
Can I take this if I'm pregnant or breastfeeding?
What side effects might I get?
Will this really lower my cholesterol?
What's the difference between the ingredients — pectin, brown rice bran, and oat fiber?
Is this safe to take long-term?
Written and reviewed by the HelloPharmacist editorial staff. Our editorial policy
Not sure if Oat Fiber Plus 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 Oat Fiber Plus’s Ingredients
Every ingredient we hold a full HelloPharmacist monograph for — uses, evidence, safety, and the complete interaction list.
Black Psyllium
Interacts with 2,025 drugsBlack psyllium is a soluble-fiber supplement made from the seeds of a Plantago plant, used mostly to ease constipation and support digestive health. It is best known and most studied for rel...
Read the full Black Psyllium monograph → Herb & supplement monographPectin
Interacts with 23 drugsPectin is a natural soluble fiber found in fruits like apples and citrus, and it is widely used in foods and as a fiber supplement. It may modestly help with cholesterol, blood sugar, and di...
Read the full Pectin monograph → Herb & supplement monographRice Bran
Rice bran is the nutrient-rich outer layer of the rice grain and is a good source of fiber, healthy fats, and plant compounds. It is most studied for helping lower cholesterol, but for most...
Read the full Rice Bran monograph →Sources & How We Checked
Oat Fiber Plus'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 36 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.
Black Psyllium 18 references
- McGuffin M, Hobbs C, Upton R, Goldberg A, eds. American Herbal Products Association's Botanical Safety Handbook. Boca Raton, FL: CRC Press, LLC 1997.
- Gruenwald J, Brendler T, Jaenicke C. PDR for Herbal Medicines. 1st ed. Montvale, NJ: Medical Economics Company, Inc., 1998.
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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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