Chitosan Ingredients & Drug Interactions
by NutriCology
What is this page for?
First and foremost: checking Chitosan 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
Chitosan is a dietary supplement by NutriCology 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 Chitosan by NutriCology
Ask about any prescription or over-the-counter medication and we check it for interactions with Chitosan by NutriCology — 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 Chitosan by NutriCology
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. Chitosan works by binding to dietary fats in your digestive tract, which is why it's used to support weight management and postoperative recovery.
The capsule also contains inactive ingredients—hydroxypropyl methylcellulose, microcrystalline cellulose, and L-leucine—which are fillers and binders that hold the supplement together.
Does it work?
Strong evidence
The evidence for chitosan is modest. It's rated Possibly Effective for weight management (obesity) and postoperative recovery—meaning some studies support it, but the evidence isn't rock-solid.
It's also rated Possibly Effective for high blood pressure. For Crohn disease and dry eye, we don't have enough reliable evidence to say whether it works.
Talk to your pharmacist about whether it's a good fit for what you're trying to address.
How safe is it?
Well-documented data
Chitosan is generally well tolerated in the short term, but the quality of long-term safety data is limited. The most common side effects are gastrointestinal: constipation, diarrhea, gas, stomach discomfort, nausea, and throat dryness.
Some people have reported excess fat in their stools (steatorrhea). One person with kidney failure reported itching during treatment, though it's unclear if chitosan caused it.
Because chitosan comes from shellfish shells, it's not suitable for anyone with a shellfish allergy. There isn't enough safety data to use this during pregnancy or while breastfeeding—talk with your doctor for personalized guidance.
Meds to double-check
Moderate interaction found
Before you take this, double-check if you're on warfarin (a blood thinner)—chitosan may raise your bleeding risk. Also check if you take acyclovir (an antiviral for herpes or shingles)—chitosan can reduce how much of it your body absorbs, potentially making it less effective.
Use the medication checker on this page to be sure.
The bottom line
Scorecard at a glanceFully disclosed formula with strong clinical evidence behind its ingredients' uses. Moderate medication interactions have been identified, and safety information is well characterized.
Chitosan may help with weight management or recovery after surgery if you're looking for a modest boost, but the evidence is fairly limited. If you take warfarin or acyclovir, you'll need to check with your pharmacist first—this product can interfere with both.
Anyone with a shellfish allergy should avoid it, and pregnant or breastfeeding individuals should talk to their doctor before starting.
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 25, 2019.
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 Chitosan, straight from the product label.
| Brand | NutriCology |
|---|---|
| Barcode (UPC) | 713947523203 |
| Net contents | 90 Vegetarian Capsule(s) |
| Market status | On market |
| Date entered into DSLD | Feb 25, 2019 |
| DSLD ID | 191093 |
| Product type | Fiber And Other Nutrients |
| Supplement form | Capsule |
| Dietary claims / uses | Nutrient, All Other |
| Intended target group(s) | Adult (18 - 50 Years) |
Everything in this section is reproduced from the manufacturer’s own product label — it’s the label speaking, not HelloPharmacist. We show it so you can see exactly what the maker states; we don’t verify or endorse those statements.
Supplement Facts
The label details for Chitosan by NutriCology, 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: Hydroxypropyl Methylcellulose, Microcrystalline Cellulose, L-Leucine
Tap any ingredient to jump to its full detail below.
These statements are the manufacturer’s wording, reproduced from the product label — the label is saying it, not HelloPharmacist. We don’t verify or endorse them.
Formula
Chitosan is a dietary fiber derived from chitin, a polysaccharide derived from the shells of crustaceans.
A Natural Dietary Fiber
Suggested/Recommended/Usage/Directions
Suggested Use As a dietary supplement, 2 capsules with 8 ounces of water thirty to forty minutes prior to one or two meals per day, or as directed by a healthcare practitioner.
Precautions
Warning: A high quality essential fatty acid supplement such as flax seed oil, along with ample fat soluble vitamins A, D, E, and K should be taken at a meal apart from Chitosan supplementation.
Avoid this product if you are allergic to shellfish, pregnant or lactating.
Avoid this product if you are allergic to shellfish, pregnant or lactating.
Not recommended for children or teenagers.
Anyone under medical care for degenerative conditions, or using medications, should consult a healthcare professional before using Chitosan.
Not labeled for sale in California.
Storage
Keep in a cool, dry place, tightly capped.
General Statements
Innovative Nutrition
FDA Statement of Identity
Dietary Supplement
General
Rev. 005
Is this label outdated? Report a formula or label change and our pharmacy team will review it.
Chitosan by NutriCology 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 Chitosan by NutriCology
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 container45 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: Hydroxypropyl Methylcellulose, Microcrystalline Cellulose, L-Leucine. These complete the product’s ingredient list but are not active constituents.
Chitosan by NutriCology Drug Interactions
HelloPharmacist Interaction Report
Chitosan by NutriCology has documented interactions with a small number of medications.
The most serious concern is with warfarin (Coumadin), a blood thinner. In a case report, a patient's blood-thinning level (measured by INR) jumped significantly after starting chitosan 1200 mg daily; it normalized only after stopping chitosan and taking vitamin K.
This is a Moderate-severity interaction.
Read the full breakdown — every affected drug type, severity by severity
Chitosan also reduces how well your body absorbs acyclovir (Zovirax), an antiviral medication used for herpes and shingles. Studies show that taking chitosan alongside acyclovir lowers the drug's blood levels, which could reduce how well the antiviral works.
This is also Moderate severity.
Always run your exact medications 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 Chitosan?
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 Chitosan interact with 2,025 drugs. Click any drug to see the details.
2 of the 2 ingredients in Chitosan interact with drugs. Each result below shows which ingredient is responsible. Dietary Fiber Chitosan
AcyclovirAvaclyr, Sitavig, Zovirax, Zovirax Injection
How Acyclovir interacts with Chitosan — 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 Chitosan — 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 Chitosan — 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 Chitosan — 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 Chitosan — 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 Chitosan — 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 Chitosan — 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 Chitosan — 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 Chitosan — 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 Chitosan — 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 Chitosan — 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 Chitosan — 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 Chitosan — 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 Chitosan — 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 Chitosan — 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 Chitosan — 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 Chitosan — 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 Chitosan — 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 Chitosan — 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 Chitosan — 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 Chitosan — 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 Chitosan — 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 Chitosan — 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 Chitosan — 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 Chitosan — 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 Chitosan — 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 Chitosan — 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 Chitosan — 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 Chitosan — 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 Chitosan — 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 Chitosan 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 Chitosan, from the product label.
NutriCology
See all NutriCology products- Name
- NutriCology
- City
- Alameda
- State
- CA
- ZipCode
- 94502
- Phone Number
- 510.263.2000
- Web Address
- www.nutricology.com
Chitosan by NutriCology: Common Questions
Does Chitosan by NutriCology interact with any medications?
How can one product interact with so many drugs?
Where does this information come from?
Is this safe if I have a shellfish allergy?
What are the most common side effects?
Can I take this if I'm pregnant or breastfeeding?
Does chitosan actually help with weight loss?
What exactly is chitosan?
Written and reviewed by the HelloPharmacist editorial staff. Our editorial policy
Not sure if Chitosan 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 Chitosan’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
Chitosan'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
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