Diet Chitosan 500 mg Ingredients & Drug Interactions
by Source Naturals
What is this page for?
First and foremost: checking Diet Chitosan 500 mg against your medications. The heart of this page is the interaction checker and the full interaction report — how this product’s ingredients may interact with prescription and over-the-counter medicines you may be taking.
Around that, we add a pharmacist’s high-level view of the product as a whole — what’s inside, the evidence for its stated use, how transparent the label is, and what safety data exists — so you can see the full picture in one place. It’s educational information from our licensed clinical databases and the clinical staff at HelloPharmacist — not medical advice — and we don’t sell or endorse products. Our editorial policy
Diet Chitosan 500 mg is a dietary supplement by Source Naturals with 2 active ingredients. Its ingredients are commonly taken for constipation, diarrhea, high cholesterol.Based on those ingredients, 2,025 medications have a known interaction with it, the most serious rated moderate. The ingredients most likely to interact are Dietary Fiber, Chitosan. Use the checker below to test your specific medication, or read the full HelloPharmacist Interaction Report.
Check Your Meds Against Diet Chitosan 500 mg by Source Naturals
Ask about any prescription or over-the-counter medication and we check it for interactions with Diet Chitosan 500 mg by Source Naturals — 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
Ask the Pharmacist
A licensed pharmacist will answer your question by email — free, usually within 24 hours.
Got it — thank you!
A licensed pharmacist will answer within 24 hours. Keep an eye on your email (worth checking spam, just in case).
HelloPharmacist Scorecard of Diet Chitosan 500 mg by Source Naturals
Our pharmacy team’s full take, with four database checks built into the cards below — a summary of what is known, not a grade of the product itself.
What’s inside
Full disclosure
This product contains one active ingredient: chitosan, a fiber derived from shellfish shells at 500 mg per capsule. Chitosan is marketed for weight management and other uses.
The capsule also holds microcrystalline cellulose, gelatin, magnesium stearate, and silica as inactive ingredients (binders and flow agents).
Does it work?
Strong evidence
Chitosan is rated possibly effective for obesity and possibly effective for postoperative recovery based on the evidence we hold. It's also rated possibly effective for high blood pressure.
For Crohn disease and dry eye, the evidence we have isn't strong enough to rate it either way.
How safe is it?
Well-documented data
Chitosan is generally well tolerated short-term, though quality evidence is limited. Common side effects include constipation, diarrhea, gas, nausea, and stomach discomfort.
Some people report a dry throat or excessive fat in their stool. One person with kidney failure reported itching during treatment, though it's unclear if chitosan caused it.
Shellfish allergy is a concern — chitosan comes from shellfish shells. Safety data during pregnancy and breastfeeding is not sufficient; the product should be avoided in both.
Meds to double-check
Moderate interaction found
Before you take this product, check with your doctor or pharmacist if you take warfarin (Coumadin) — a blood thinner — or acyclovir (Zovirax), an antiviral. Chitosan may reduce how well acyclovir works and may raise your bleeding risk on warfarin.
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.
Chitosan may be worth considering if you're exploring options for weight management, but it's not for you if you take warfarin or acyclovir — the interactions are real and documented. Talk with your doctor or pharmacist about your medications before starting, especially if you have a shellfish allergy, and avoid it if you're pregnant or breastfeeding.
Educational only — not medical advice; always confirm with your pharmacist. Our editorial policy · How we use AI
Assessment coverage: 2 of 2 active ingredients matched to our full ingredient reviews (monographs). Based on the product label dated Feb 26, 2020.
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 Diet Chitosan 500 mg, straight from the product label.
| Brand | Source Naturals |
|---|---|
| Barcode (UPC) | 021078010241 |
| Net contents | 240 Capsule(s) |
| Market status | On market |
| Date entered into DSLD | Feb 26, 2020 |
| DSLD ID | 213853 |
| Product type | Fiber And Other Nutrients |
| Supplement form | Capsule |
| Dietary claims / uses | All Other, Structure/Function |
| Intended target group(s) | Adult (18 - 50 Years), Gluten Free, Dairy Free, Sugar 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 Diet Chitosan 500 mg by Source Naturals, sourced from the NIH Dietary Supplement Label Database.
Supplement Facts
| Ingredient | Amount | % DV |
|---|---|---|
| Calories | 5 Calorie(s) | -- |
| Total Carbohydrates | 1 Gram(s) | 1% |
| Dietary Fiber | 1 Gram(s) | 4% |
| Chitosan | 1 Gram(s) | -- |
Other ingredients: Microcrystalline Cellulose, Gelatin, Magnesium Stearate, 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 Use: 2 capsules 1/2 hour before lunch and 2 capsules 1/2 hour before dinner with 8 ounces of liquid. Drink at least 8 glasses of fluid daily. For best results, take this product in conjunction with the enclosed Maximum Metabolism Weight Loss Plan and a multiple vitamin such as Source Naturals Life Force.
Precautions
Caution: If you are pregnant, may become pregnant, breastfeeding, allergic to shellfish or taking any medication, consult your health care professional before using this product. Fat-soluble vitamins (A, E, D or K), essential fatty acids or medications should be taken 4 hours before or after ingesting chitosan to ensure absorption. Take this product with large amounts of liquid. If you do not drink enough liquid, the product may cause constipation. Discontinue use if intestinal discomfort or constipation occurs.
Caution: If you are pregnant, may become pregnant, breastfeeding, allergic to shellfish or taking any medication, consult your health care professional before using this product.
Do not use if either tamper-evident seal is broken or missing.
Keep out of the reach of children.
Contains shellfish (crab, shrimp, and lobster).
Formulation
Contains no yeast, dairy, egg, gluten, corn, soy or wheat. Contains no sugar, starch, preservatives, or artificial color, flavor or fragrance.
FDA Disclaimer Statement
These statements have not been evaluated by the Food and Drug Administration. This product is not intended to diagnose, treat, cure or prevent any disease.
Formula
Breakthrough fiber
Chitosan, a fiber derived from chitin in shellfish, is a nondigestible aminopolysaccharide. Chitosan is synthesized by removing acetyl groups from chitin through a process called deacetylation. This process enhances the activity of chitosan by improving its solubility in the acidic environment of the stomach. When taken in conjunction with the Maximum Metabolism Weight Loss Plan, body fat may be reduced.
FDA Statement of Identity
Dietary Supplement
Storage
Store in a cool, dry place.
Is this label outdated? Report a formula or label change and our pharmacy team will review it.
Diet Chitosan 500 mg by Source Naturals 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 Diet Chitosan 500 mg by Source Naturals
These are the 2 active ingredients this product is made of. Select any to open its full monograph.
Serving size2 Capsule(s) Dosage formCapsule 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.
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 & interactionsChitosan
Interacts with3 drugs
Chitosan is a fiber-like substance made from the shells of shrimp, crabs, and other shellfish, often marketed for weight loss and cholesterol. The evi...
Chitosan monograph & interactionsOther (inactive) ingredients: Microcrystalline Cellulose, Gelatin, Magnesium Stearate, Silica. These complete the product’s ingredient list but are not active constituents.
Diet Chitosan 500 mg by Source Naturals Drug Interactions
HelloPharmacist Interaction Report
Diet Chitosan 500 mg by Source Naturals interacts with a small number of medications through its chitosan content.
The most serious concern is with warfarin (Coumadin), a blood thinner — chitosan may increase bleeding risk. One case report documented a patient whose warfarin level (measured by INR) rose significantly after starting chitosan 1200 mg daily; the level came back down once chitosan was stopped and vitamin K was given.
Read the full breakdown — every affected drug type, severity by severity
Chitosan can also reduce how well your body absorbs acyclovir (Zovirax), an antiviral medication for herpes. Research shows that taking chitosan alongside acyclovir lowers the drug's blood levels, which could mean the medication doesn't work as well as it should.
Alone, these interactions span 3 individual medications. If you take any prescription medication, run it through the search tool on this page before you start.
Check your own medications below · Editorial policy · How we use AI
Want to check YOUR meds against Diet Chitosan 500 mg?
Ask about interactions with your drugs in plain English — “Can I take it with lisinopril?” — and we find you the answer in seconds, ingredient by ingredient.
Go to the checkerIngredients driving the most interactions
Individual Drug Interactions
The ingredients in Diet Chitosan 500 mg interact with 2,025 drugs. Click any drug to see the details.
2 of the 2 ingredients in Diet Chitosan 500 mg interact with drugs. Each result below shows which ingredient is responsible. Dietary Fiber Chitosan
AcyclovirAvaclyr, Sitavig, Zovirax, Zovirax Injection
How Acyclovir interacts with Diet Chitosan 500 mg — through 2 ingredients. Tap an ingredient for the detail:
ChitosanAcyclovir (zovirax) Moderate
Interaction Summary
Chitosan can reduce the absorption of acyclovir, potentially increasing the risk for treatment failure.
Read the full Chitosan + Acyclovir 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 + Acyclovir interactionAlogliptin, MetforminKazano
How Alogliptin, Metformin interacts with Diet Chitosan 500 mg — 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 interactionCanagliflozin, MetforminInvokamet
How Canagliflozin, Metformin interacts with Diet Chitosan 500 mg — 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 Diet Chitosan 500 mg — 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 Diet Chitosan 500 mg — 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 interactionDapagliflozin Propanediol, MetforminXigduo XR
How Dapagliflozin Propanediol, Metformin interacts with Diet Chitosan 500 mg — 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 Diet Chitosan 500 mg — 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 interactionEmpagliflozin, Linagliptin, Metformin HydrochlorideTrijardy XR
How Empagliflozin, Linagliptin, Metformin Hydrochloride interacts with Diet Chitosan 500 mg — 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, Linagliptin, Metformin Hydrochloride interactionEmpagliflozin, MetforminSynjardy
How Empagliflozin, Metformin interacts with Diet Chitosan 500 mg — 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 interactionEmpagliflozin, Metformin HydrochlorideSynjardy XR
How Empagliflozin, Metformin Hydrochloride interacts with Diet Chitosan 500 mg — 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 Hydrochloride interactionErtugliflozin, Metformin HydrochlorideSegluromet
How Ertugliflozin, Metformin Hydrochloride interacts with Diet Chitosan 500 mg — 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 Diet Chitosan 500 mg — 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 Diet Chitosan 500 mg — 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 Diet Chitosan 500 mg — 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 + Linagliptin, Metformin Hydrochloride interactionLithium Carbonate (prescription Drug)Eskalith, Lithium Carbonate
How Lithium Carbonate (prescription Drug) interacts with Diet Chitosan 500 mg — 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) interactionMetforminGlucophage, Metformin
How Metformin interacts with Diet Chitosan 500 mg — 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 Diet Chitosan 500 mg — 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 Hydrochloride interactionMetformin, LinagliptinJentadueto
How Metformin, Linagliptin interacts with Diet Chitosan 500 mg — 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 Diet Chitosan 500 mg — 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 interactionMetformin, SitagliptinJanumet, Janumet XR
How Metformin, Sitagliptin interacts with Diet Chitosan 500 mg — 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, Sitagliptin interactionOlanzapineZyprexa
How Olanzapine interacts with Diet Chitosan 500 mg — through 1 ingredient. Tap an ingredient for the detail:
Dietary FiberOral Drugs, Olanzapine (zyprexa) Moderate
Interaction Summary
Theoretically, psyllium might increase, decrease, or have no effect on the absorption of oral drugs.
Read the full Dietary Fiber + Olanzapine interactionSaxagliptin, Metformin XrKombiglyze
How Saxagliptin, Metformin Xr interacts with Diet Chitosan 500 mg — 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 + Saxagliptin, Metformin Xr interactionSitagliptin, MetforminZituvimet
How Sitagliptin, Metformin interacts with Diet Chitosan 500 mg — 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 + Sitagliptin, Metformin interactionWarfarinWarfarin
How Warfarin interacts with Diet Chitosan 500 mg — through 2 ingredients. Tap an ingredient for the detail:
ChitosanWarfarin (coumadin) Moderate
Interaction Summary
Theoretically, chitosan might increase the risk of bleeding when taken with warfarin.
Read the full Chitosan + Warfarin 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 + Warfarin interactionWarfarin SodiumCoumadin, Panwarfin, Sofarin
How Warfarin Sodium interacts with Diet Chitosan 500 mg — through 2 ingredients. Tap an ingredient for the detail:
ChitosanWarfarin (coumadin) Moderate
Interaction Summary
Theoretically, chitosan might increase the risk of bleeding when taken with warfarin.
Read the full Chitosan + Warfarin Sodium 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 + Warfarin Sodium interactionPioglitazone, MetforminActoPlus Met
How Pioglitazone, Metformin interacts with Diet Chitosan 500 mg — 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 + Pioglitazone, Metformin interaction"phentolamineOraVerse, Rogitine, Ryzumvi
How "phentolamine interacts with Diet Chitosan 500 mg — through 1 ingredient. Tap an ingredient for the detail:
Dietary 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 + "phentolamine interaction6-mercaptopurinePurinethol
How 6-mercaptopurine interacts with Diet Chitosan 500 mg — through 1 ingredient. Tap an ingredient for the detail:
Dietary 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 + 6-mercaptopurine interactionAbacavirZiagen
How Abacavir interacts with Diet Chitosan 500 mg — through 1 ingredient. Tap an ingredient for the detail:
Dietary 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 + Abacavir interactionAbacavir Sulfate, Dolutegravir, LamivudineTriumeq
How Abacavir Sulfate, Dolutegravir, Lamivudine interacts with Diet Chitosan 500 mg — through 1 ingredient. Tap an ingredient for the detail:
Dietary 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 + Abacavir Sulfate, Dolutegravir, Lamivudine interactionEach ingredient & the kinds of drugs it affects
For each ingredient in Diet Chitosan 500 mg with known interactions, here are the types of medications they can affect. Open any type for the detail — or search your exact drug in the checker above.
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.
Chitosan
Acyclovir (Zovirax)
Chitosan can reduce the absorption of acyclovir, potentially increasing the risk for treatment failure.
Clinical research in humans shows that taking chitosan along with acyclovir 200 mg reduces acyclovir absorption. Concomitant administration of chitosan 400 mg or 1000 mg reduced the acyclovir area under the curve (AUC) and peak plasma concentration by about 30% and 40%, respectively, compared with control. Concomitant administration with chitosan 1000 mg also increased time to peak concentration from 1 hour to 2 hours. In vitro research suggests that the mechanism for reduced absorption is due to acyclovir entrapment in chitosan-mucus complexes, which reduces intestinal absorption.
Warfarin (Coumadin)
Theoretically, chitosan might increase the risk of bleeding when taken with warfarin.
In a case report, a patient taking warfarin had a significantly increased international normalized ratio (INR) after starting chitosan 1200 mg daily. The INR normalized after chitosan was discontinued and vitamin K was administered. The patient once again started taking chitosan and again had a significant increase in INR. The INR stabilized again once chitosan was discontinued. Researchers theorize that this interaction might occur because chitosan decreases absorption of fat-soluble vitamins, including vitamin K, which could increase the anticoagulant effect of warfarin.
Brand information
Manufacturer and brand details for Diet Chitosan 500 mg, from the product label.
Source Naturals
- Name
- Source Naturals, Inc.
- Street Address
- P. O. Box 2118
- City
- Santa Cruz
- State
- CA
- ZipCode
- 95062
- Web Address
- www.sourcenaturals.com
Diet Chitosan 500 mg by Source Naturals: Common Questions
Does Diet Chitosan 500 mg by Source Naturals 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 have a shellfish allergy?
What side effects should I watch for?
Is it safe to take while pregnant or breastfeeding?
Does chitosan actually help with weight loss?
Written and reviewed by the HelloPharmacist editorial staff. Our editorial policy
Not sure if Diet Chitosan 500 mg is safe with your meds?
Our pharmacists answer your medication & supplement questions — free.
Label information is sourced from the NIH Dietary Supplement Label Database and reflects the product version on file; always read your actual product label. This page is for education only and is not a substitute for professional medical advice. Confirm with your pharmacist or doctor before combining supplements and medications.
The Full Monographs Behind Diet Chitosan 500 mg’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 monographChitosan
Interacts with 3 drugsChitosan is a fiber-like substance made from the shells of shrimp, crabs, and other shellfish, often marketed for weight loss and cholesterol. The evidence for these benefits is weak, and an...
Read the full Chitosan monograph →Sources & How We Checked
Diet Chitosan 500 mg's label data comes from the NIH Dietary Supplement Label Database; the ingredient interaction data is from the Natural Medicines database, reviewed by our pharmacists.
- NIH Dietary Supplement Label Database (DSLD) — The official product label on file for this supplement.
- Natural Medicines (Therapeutic Research Center) — Evidence-graded clinical reference behind the ingredient interaction data.
Content is written and reviewed by licensed HelloPharmacist pharmacists. See our data sources and editorial standards for how this information is built and checked.
The 35 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.
- Covington TR, et al. Handbook of Nonprescription Drugs. 11th ed. Washington, DC: American Pharmaceutical Association, 1996.
- Etman M. Effect of a bulk forming laxative on the bioavailablility of carbamazepine in man. Drug Dev Ind Pharm 1995;21:1901-6.
- Perlman BB. Interaction between lithium salts and ispaghula husk. Lancet 1990;335:416.
- Vaswani SK, Hamilton RG, Valentine MD, Adkinson NF. Psyllium laxative-induced anaphylaxis, asthma, and rhinitis. Allergy 1996;51:266-8. PubMed
- Lantner RR, Espiritu BR, Zumerchik P, Tobin MC. Anaphylaxis following ingestion of a psyllium-containing cereal. JAMA 1990;264:2534-6. DOI
- Kaplan MJ. Anaphylactic reaction to "Heartwise." N Engl J Med 1990;323:1072-3. DOI
- Nordstrom M, Melander A, Robertsson E, Steen B. Influence of wheat bran and of a bulk-forming ispaghula cathartic on the bioavailability of digoxin in geriatric in-patients. Drug Nutr Interact 1987;5:67-9..
- Robinson DS, Benjamin DM, McCormack JJ. Interaction of warfarin and nonsystemic gastrointestinal drugs. Clin Pharmacol Ther 1971;12:491-5. PubMed
- Garcia JJ, Fernandez N, Diez MJ, et al. Influence of two dietary fibers in the oral bioavailability and other pharmacokinetic parameters of ethinyloestradiol. Contraception 2000;62:253-7. PubMed
- Fernandez N, Lopez C, Díez R, et al. Drug interactions with the dietary fiber Plantago ovata husk. Expert Opin Drug Metab Toxicol 2012;8(11):1377-86.
- Semen plantaginis in: WHO Monographs on Selected Medicinal Plants, volume 1. World Health Organization, Geneva, 1999. Available at http://apps.who.int/medicinedocs/en/d/Js2200e/. Accessed November 26, 1026.
- Code of Federal Regulations, Title 21 (21CFR 101.17). Food labeling warning, notice, and safe handling statements. Available at www.ecfr.gov/cgi-bin/text-idx?SID=20f647d3b74161501f46564b915b4048&mc=true&node=se21.2.101_117&rgn=div8. Accessed December 3, 2
- Code of Federal Regulations, Title 21 (21CFR 201.319). Specific labeling requirements - water-soluble gums, hydrophilic gums, and hydrophilic mucilloids. Available at www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfcfr/CFRSearch.cfm?fr=201.319. Accessed Dece
- Diez R, Garcia JJ, Diez MJ, Sierra M, Sahagun AM, Fernandez N. Influence of Plantago ovata husk (dietary fiber) on the bioavailability and other pharmacokinetic parameters of metformin in diabetic rabbits. BMC Complement Altern Med. 2017 Jun 7;17(1):298. PubMed
- Chiu AC, Sherman SI. Effects of pharmacological fiber supplements on levothyroxine absorption. Thyroid. 1998;8(8):667-71. PubMed
- Merrick C, Madden CA, Capurso NA. A Case of Blunted Orally Disintegrating Olanzapine Effect Due to Coadministered Psyllium. J Clin Psychiatry 2021;82(2):20cr13633. PubMed
Chitosan 17 references
- Jing SB, Li L, Ji D, et al. Effect of chitosan on renal function in patients with chronic renal failure. J Pharm Pharmacol 1997;49:721-3. PubMed
- Pittler MH, Abbot NC, Harkness EF, Ernst E. Randomized, double-blind trial of chitosan for body weight reduction. Eur J Clin Nutr 1999;53:379-81. PubMed
- Ho SC, Tai ES, Eng PH, et al. In the absence of dietary surveillance, chitosan does not reduce plasma lipids or obesity in hypercholesterolaemic obese Asian subjects. Singapore Med J 2001;42:6-10.
- Bokura H, Kobayashi S. Chitosan decreases total cholesterol in women: a randomized, double-blind, placebo-controlled trial. Eur J Clin Nutr 2003;57:721-5. PubMed
- Mhurchu CN, Poppitt SD, McGill AT, et al. The effect of the dietary supplement, Chitosan, on body weight: a randomised controlled trial in 250 overweight and obese adults. Int J Obes Relat Metab Disord 2004;28:1149-56. PubMed
- Huang SS, Sung SH, Chiang CE. Chitosan potentiation of warfarin effect. Ann Pharmacother 2007;41:1912-4. PubMed
- Tsai, G. J. and Su, W. H. Antibacterial activity of shrimp chitosan against Escherichia coli. J Food Prot. 1999;62(3):239-243. PubMed
- Wuolijoki, E., Hirvela, T., and Ylitalo, P. Decrease in serum LDL cholesterol with microcrystalline chitosan. Methods Find.Exp Clin Pharmacol. 1999;21(5):357-361. PubMed
- Nelson, J. L., Alexander, J. W., Gianotti, L., Chalk, C. L., and Pyles, T. Influence of dietary fiber on microbial growth in vitro and bacterial translocation after burn injury in mice. Nutrition 1994;10(1):32-36.
- Schiller RN, Barrager E, Schauss EA, and et al. A randomized, double-blind, placebo-controlled study examining the effects of a rapidly soluble chitosan dietary supplement on weight loss and body composition in overweight and mildly obese individuals. J
- Koide, S. S. Chitin-chitosan: properties, benefits and risks. Nutrition Research 1998;8(6):1091-1101. DOI
- Maezaki Y, Tsuji K, Nakawa, and et al. Hypocholesterolaemic effect of chitosan in adult males. Biosc Biochem Biotech 1993;57:1439-1444.
- Kubbinga M, Nguyen MA, Staubach P, et al. The influence of chitosan on the oral bioavailability of acyclovir-a comparative bioavailability study in humans. Pharm Res 2015;32(7):2241-9. PubMed
- Jull AB, Ni Mhurchu C, Bennett DA, et al. Chitosan for overweight or obesity. Cochrane Database Syst Rev 2008;(3):CD003892. PubMed
- Schmidl D, Werkmeister R, Kaya S, et al. A Controlled, Randomized Double-Blind Study to Evaluate the Safety and Efficacy of Chitosan-N-Acetylcysteine for the Treatment of Dry Eye Syndrome. J Ocul Pharmacol Ther. 2017;33(5):375-382.
- Moraru C, Mincea MM, Frandes M, Timar B, Ostafe V. A meta-analysis on randomised controlled clinical trials evaluating the effect of the dietary supplement chitosan on weight loss, lipid parameters and blood pressure. Medicina (Kaunas). 2018;54(6):109. PubMed
- García MA, Hensler G, Al-Gousous J, Pielenhofer J, Wagner M, Lennernäs H, Langguth P. Novel food drug interaction mechanism involving acyclovir, chitosan and endogenous mucus. Drug Metab Pharmacokinet. 2023;49:100491. PubMed
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