Drug & supplement interaction

Sitostanol + Trospium

Trospium brand names: Sanctura, Trosec, Regurin.

No Known Interaction

Medically reviewed by Dr. Brian Staiger, PharmD, BCPS · Updated July 2026 · Pair last verified Sep 20, 2026

The bottom line No known interaction

We found no known interaction between Sitostanol and Trospium in our sources. Absence of a documented interaction is not the same as proven safety, and does not guarantee one does not exist. Do not start, stop, or change a medication or supplement based on this page; confirm with your pharmacist or doctor first. Additionally, although there is no interaction, the label for Trospium states a food rule worth keeping to.

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Interaction report

Sitostanol and Trospium

We checked these two against our interaction database. Here is what we found.

No Known Interaction Found

We did not find a documented interaction between Trospium and Sitostanol in our sources. This does not guarantee that the combination is completely free of risk — there is often limited research on supplements and herbal products, especially around drug interactions.

Worth understanding: our licensed dataset holds no drug-interaction record for Sitostanol at all — not against Trospium, and not against any other medication we track. This verdict therefore rests on the absence of any recorded data, not on research that looked at this combination and found nothing. We cannot rule an interaction out.

If you decide to take both, the practical routine is simple: add one new thing at a time and note the date you started it. If the combination is going to disagree with you, it usually shows in the first days to a couple of weeks — and a start date turns “I’ve been feeling off” into something a pharmacist can actually work with. Do not stop a prescribed medicine on your own.

Always talk with your pharmacist or doctor before making changes to your medications or supplements, particularly if you take several medications or have an ongoing health condition.

Sitostanol safety at a glance

Sitostanol overall Use caution Generally well tolerated in foods, but high intakes and certain medical conditions warrant caution.

Pregnancy Use caution Not well studied in pregnancy; food amounts may be acceptable, but supplement-level doses should be avoided unless advised by a doctor.

Breastfeeding Use caution Limited safety data during breastfeeding, so use only with guidance from your healthcare provider.

Safety guidance is general; always confirm with your pharmacist or doctor for your situation.

Still wondering about combining Trospium and Sitostanol? Ask Dr. Brian Staiger, PharmD, BCPS directly ›

What to actually watch for

What Sitostanol Itself Has Been Linked To

This is not an interaction — nothing below involves Trospium. It is the side-effect record for Sitostanol on its own, from the licensed Natural Medicines monograph. If something new turns up after you add Sitostanol, this list is the first place to look.

Diarrhea Additional detail
“Orally, sitostanol is well tolerated. Adverse effects have not been reported in clinical trials in adults or children. However, because sitostanol decreases cholesterol absorption in the gut, it might be expected to produce some gastrointestinal symptoms like diarrhea and excess amounts of fat in the stool (steatorrhea).”

Sitostanol · Natural Medicines adverse-effect record, reported in diarrhea.
6 sources cited

3888. Vuorio AF, Gylling H, Turtola H, et al. Stanol ester margarine alone and with simvastatin lowers serum cholesterol in families with familial hypercholesterolemia caused by the FH-north karelia mutation. Arterioscler Thromb Vasc Biol 2000;20:500-6. PubMed

5336. Weststrate JA, Meijer GW. Plant sterol-enriched margarines and reduction of plasma total- and LDL-cholesterol concentrations in normocholesterolaemic and mildly hypercholesterolaemic subjects. Eur J Clin Nutr 1998;52:334-43. PubMed

5429. Gylling H, Miettinen TA. Cholesterol reduction by different plant stanol mixtures and with variable fat intake. Metabolism 1999;48:575-80. PubMed

5430. Gylling H, Puska P, Vartiainen E, et al. Serum sterols during stanol ester feeding in a mildly hypercholesterolemic population. J Lipid Res 1999;40:593-600. DOI

5431. Gylling H, Radhakrishnan R, Miettinen TA. Reduction of serum cholesterol in postmenopausal women with previous myocardial infarction and cholesterol malabsorption induced by dietary sitostanol ester margarine: women and dietary sitostanol. Circulation 199 PubMed

5432. Gylling H, Miettinen TA. Serum cholesterol and cholesterol and lipoprotein metabolism in hypercholesterolaemic NIDDM patients before and during sitostanol ester-margarine treatment. Diabetologia 1994;37:773-80. DOI
“Although adverse effects have not been reported, sitostanol decreases cholesterol absorption in the gut, and it might be expected to produce some gastrointestinal symptoms like diarrhea and excess amounts of fat in the stool (steatorrhea).”

Sitostanol · Natural Medicines adverse-effect record, reported in diarrhea.

Everything above comes from the Natural Medicines adverse-effect record for Sitostanol — expand a row for the licensed statement it rests on. We read the ADVERSE REACTIONS section of Trospium’s FDA label too, and the two lists don’t meaningfully overlap — which is why no Trospium column appears here.

How to take them

Some Trospium Products Have a Food Rule — Sitostanol Should Not Break It

At least one FDA label for a product containing Trospium says to take it on an empty stomach. Most supplements — Sitostanol included — are taken with a meal, so the easy mistake is swallowing both together at breakfast. Where that rule applies, keep Trospium on its own and move Sitostanol to a meal later in the day.

This may not be true of your version. Food instructions belong to the product, not the ingredient: two Trospium products can carry different directions, and extended-release forms often differ from immediate-release ones. The label we read is quoted below — check the directions on your own box or bottle, or ask your pharmacist, for how to take the exact product you were given.

Trospium Chloride Extended-Release Capsules should be dosed with water on an empty stomach, at least one hour before a meal.

From the Dosage and Administration section of the FDA label we read for Trospium — where that label names a specific product, the instruction is that product's. See the Trospium drug page ›

A food rule is not an interaction — it is about how much of the medicine you absorb. The directions that came with your own product, and your pharmacist, outrank anything on this page.

Everything else you take

See Every Supplement That Interacts With Trospium

This page covers Sitostanol only. If you take other supplements — a multivitamin, a sleep aid, something for joints — the Trospium page lists 47 supplements it has a documented interaction with, worst first, each one explained.

The most serious there right now: Activated Charcoal (major), Henbane (major), Scopolia (major), Angel's Trumpet (moderate) and Bacopa (moderate).

By severity: 3 major · 33 moderate · 11 minor.

From our pharmacist’s overview on the Trospium page

“Trospium (Sanctura, Regurin) calms an overactive bladder by blocking acetylcholine, and most of the 47 supplements flagged against it press on that same nerve signal. Thirty carry anticholinergic activity of their own, adding dry mouth, constipation, blurred vision, and confusion, and two of the three major ratings sit in that group: h…”

Reviewed by 2 · Jul 18, 2026

Open the Trospium interaction page

One more smart check

Taking Sitostanol as Part of a Dietary Supplement Product? Check It for Interactions

We hold 9 real supplement products containing Sitostanol, each one broken down to its full ingredient list — and combination products often carry several ingredients besides Sitostanol. Even though Sitostanol itself has no known interaction with Trospium, another ingredient on your label might. Find your product and we’ll check every ingredient on its label:

How much people look this up

Where Sitostanol and Trospium Sit Against Everything Else

Out of every supplement and medication people look up on HelloPharmacist, here is where these two land this week — and which way each has been moving.

Supplement Sitostanol

Steady interest

#846 of 1,452 supplements looked up here in the last 7 days

29 days ago today

Medication Trospium

Steady interest

#2,319 of 2,830 medications looked up here in the last 7 days

29 days ago today

Position among everything looked up on this site, not a measure of how commonly either one is used or how important it is. A supplement can climb this list because of a news story. It counts every request to the page, automated ones included, and nothing here identifies anyone.

Where does our data come from?

Source: the Natural Medicines (TRC Healthcare) clinical database — the evidence-graded professional reference for herb & supplement interactions.
Citation library: 103,510 references behind our interaction content, 65,311 of them resolved to verified PubMed/DOI sources. See every Sitostanol reference on this page ↓
Freshness: we automatically re-check this combination every week — this pair was last verified September 20, 2026. The Sitostanol and Trospium records this page draws on were last updated July 10, 2026.
What “no known interaction” means: no documented interaction in the sources above — not a guarantee of safety. Supplements are studied far less than prescription drugs, so we say exactly what the evidence supports, and nothing more.

Data structure & sourcing designed and verified by Dr. Brian Staiger, PharmD, BCPS.

Supplement

About Sitostanol

What is Sitostanol?

High cholesterol
Heart health support
Lowering LDL cholesterol
General cardiovascular wellness

Sitostanol is a plant stanol that can modestly lower LDL ("bad") cholesterol by blocking the absorption of cholesterol in the gut. It is best known when combined with related stanols and sterols in fortified foods and is generally considered safe for most adults, but it is not a replacement for prescribed cholesterol medicines. Talk with your pharmacist or doctor before starting it, especially if you take heart or cholesterol drugs.

Plant sterol/stanol derived from vegetable oils, wood pulp, and other plant sources · Fortified margarine and spreads, yogurt drinks, capsules, tablets (often as sitostanol esters)

An interaction check asks whether these two react with each other — it does not ask whether Sitostanol is a good idea for someone in your situation. Here is what our Sitostanol record says about it on its own.

Sitostanol: dosing

There is no official supplement dose set specifically for sitostanol on its own. In studies of plant stanols and sterols, cholesterol-lowering effects are usually seen with daily amounts spread across meals, often delivered through fortified spreads or supplements.The best approach is to follow the product label and not exceed the recommended amount.

From our Sitostanol monograph — the full record covers uses, side effects and every documented interaction.

Read the full Sitostanol monograph & all interactions

Medication

About Trospium

What Is Trospium Used For?

Brand names: Sanctura, Trosec, Regurin

Trospium — available as tablets and extended-release capsules — is used to treat overactive bladder (OAB). It targets three main symptoms: the sudden, hard-to-control urge to urinate (urgency), leaking urine when that urge hits (urge urinary incontinence), and needing to urinate much more often than usual (urinary frequency).

Both Trospium Chloride Tablets and Trospium Chloride Extended-Release Capsules carry this indication. Your prescriber will choose the formulation that fits your schedule and health history.

See full Trospium drug information

Keep checking

Other Drugs & Sitostanol

Browse every other medication we’ve checked against Sitostanol — both the ones with a known interaction and the ones without. Select any drug for the full detail.

0Major

0Moderate

0Minor

2,829No known interaction

2,829 No interaction

No interaction 2,829 drugs checked — show the list

We also checked Sitostanol against these medications and found no known interaction in our sources. Open any page to confirm.

Showing the 60 most looked-up of 2,829 medications checked with no known interaction — see the full Sitostanol list.

See the full Sitostanol interactions page

See every supplement checked against Trospium, ranked by severity

Evidence & sources

Sitostanol References

The 26 references that drive our Sitostanol monograph and interaction data, from the evidence-graded Natural Medicines (TRC Healthcare) database. Citations with a link open the study on PubMed or the publisher’s site.

Vuorio AF, Gylling H, Turtola H, et al. Stanol ester margarine alone and with simvastatin lowers serum cholesterol in families with familial hypercholesterolemia caused by the FH-north karelia mutation. Arterioscler Thromb Vasc Biol 2000;20:500-6. PubMed
Becker M, Staab D, Von Bergmann K. Treatment of severe familial hypercholesterolemia in childhood with sitosterol and sitostanol. J Pediatr 1993;122:292-6. PubMed
Weststrate JA, Meijer GW. Plant sterol-enriched margarines and reduction of plasma total- and LDL-cholesterol concentrations in normocholesterolaemic and mildly hypercholesterolaemic subjects. Eur J Clin Nutr 1998;52:334-43. PubMed
Gylling H, Miettinen TA. Cholesterol reduction by different plant stanol mixtures and with variable fat intake. Metabolism 1999;48:575-80. PubMed
Gylling H, Puska P, Vartiainen E, et al. Serum sterols during stanol ester feeding in a mildly hypercholesterolemic population. J Lipid Res 1999;40:593-600. DOI
Gylling H, Radhakrishnan R, Miettinen TA. Reduction of serum cholesterol in postmenopausal women with previous myocardial infarction and cholesterol malabsorption induced by dietary sitostanol ester margarine: women and dietary sitostanol. Circulation 199 PubMed
Gylling H, Miettinen TA. Serum cholesterol and cholesterol and lipoprotein metabolism in hypercholesterolaemic NIDDM patients before and during sitostanol ester-margarine treatment. Diabetologia 1994;37:773-80. DOI
Gylling H, Miettinen TA. Effects of inhibiting cholesterol absorption and synthesis on cholesterol and lipoprotein metabolism in hypercholesterolemic non-insulin-dependent diabetic men. J Lipid Res 1996;37:1776-85. DOI
Gylling H, Puska P, Vartiainen E, et al. Retinol, vitamin D, carotenes and alpha-tocopherol in serum of a moderately hypercholesterolemic population consuming sitostanol ester margarine. Am J Cardiol 1999;145:279-85.
Hallikainen MA, Uusitupa MI. Effects of 2 low-fat stanol ester-containing margarines on serum cholesterol concentrations as part of a low-fat diet in hypercholesterolemic subjects. Am J Clin Nutr 1999;69:403-10. PubMed
Heinemann T, Kullak-Ublick GA, Pietruck B, von Bergmann K. Mechanisms of action of plant sterols on inhibition of cholesterol absorption. Comparison of sitosterol and sitostanol. Eur J Clin Pharmacol 1991;40 Suppl 1:S59-63. DOI
Jones PJ, Ntanios FY, Raeini-Sarjaz M, et al. Cholesterol-lowering efficacy of a sitostanol-containing phytosterol mixture with a prudent diet in hyperlipidemic men. Am J Clin Nutr 1999;69:1144-50. PubMed
Gylling H, Siimes MA, Miettinen TA. Sitostanol ester margarine in dietary treatment of children with familial hypercholesterolemia. J Lipid Res 1995;36:1807-12. DOI
Miettinen TA, Puska P, Gylling H, et al. Reduction of serum cholesterol with sitostanol-ester margarine in a mildly hypercholesterolemic population. N Engl J Med 1995;333(20):1308-12. PubMed
Vanhanen HT, Kajander J, Lehtovirta H. Serum levels, absorption efficiency, faecal elimination and synthesis of cholesterol during increasing doses of dietary sitostanol esters in hypercholesterolaemic subjects. Clin Sci (Colch) 1994;87:61-7. PubMed
Plat J, van Onselen EN, van Heugten MM, Mensink RP. Effects on serum lipids, lipoproteins and fat soluble antioxidant concentrations of consumption frequency of margarines and shortenings enriched with plant stanol esters. Eur J Clin Nutr 2000;54:671-7. PubMed
Hallikainen MA, Sarkkinen ES, Uusitupa MI. Effects of low-fat stanol ester enriched margarines on concentrations of serum carotenoids in subjects with elevated serum cholesterol concentrations. Eur J Clin Nutr 1999;53:966-9. PubMed
Hallikainen MA, Sarkkinen ES, Gylling H, et al. Comparison of the effects of plant sterol ester and plant stanol ester-enriched margarines in lowering serum cholesterol concentrations in hypercholesterolaemic subjects on a low-fat diet. Eur J Clin Nutr PubMed
Williams CL, Bollella MC, Strobino BA, et al. Plant stanol ester and bran fiber in childhood: effects on lipids, stool weight and stool frequency in preschool children. J Am Coll Nutr 1999;18:572-81. PubMed
Tammi A, Ronnemaa T, Gylling H, et al. Plant stanol ester margarine lowers serum total and low-density lipoprotein cholesterol concentrations of healthy children: the STRIP project. Spec Turku Coronary Risk Factors Intervention Project. J Pediatr 2000;1 DOI
Mensink RP, de Jong A, Lütjohann D, Haenen GR, Plat J. Plant stanols dose-dependently decrease LDL-cholesterol concentrations, but not cholesterol-standardized fat-soluble antioxidant concentrations, at intakes up to 9 g/d. Am J Clin Nutr. 2010 Jul;92(1): PubMed
Vásquez-Trespalacios EM, Romero-Palacio J. Efficacy of yogurt drink with added plant stanol esters (Benecol®, Colanta) in reducing total and LDL cholesterol in subjects with moderate hypercholesterolemia: a randomized placebo-controlled crossover trial NC
Malhotra A, Shafiq N, Arora A, Singh M, Kumar R, Malhotra S. Dietary interventions (plant sterols, stanols, omega-3 fatty acids, soy protein and dietary fibers) for familial hypercholesterolaemia. Cochrane Database Syst Rev. 2014 Jun 10;6:CD001918. PubMed
Hallikainen M, Kurl S, Laakso M, Miettinen TA, Gylling H. Plant stanol esters lower LDL cholesterol level in statin-treated subjects with type 1 diabetes by interfering the absorption and synthesis of cholesterol. Atherosclerosis. 2011 Aug;217(2):473-8. PubMed
Wang S, Zhao W, Li J, et al. Association of Dietary Phytosterols Intake and Survival of Esophageal Squamous Cell Carcinoma: A Prospective Cohort Study. Nutr Cancer 2022;74(10):3582-3591. PubMed
Guo P, Feng R, Li Z, Han T. Gender differences in the relationships between dietary phytosterols intake and prevalence of obesity in Chinese population. Food Sci Nutr 2022;11(1):569-577. PubMed

Medication overviews come from MedlinePlus (NIH); supplement label data from the NIH Dietary Supplement Label Database. Content is written and reviewed by licensed HelloPharmacist pharmacists — see our data sources and editorial standards.

Pharmacist Counseling Corner

Taking Sitostanol and Trospium Together: Common Questions

Is it safe to take Sitostanol with Trospium?

We do not list a known interaction between Sitostanol and Trospium. That does not guarantee the combination is risk-free, so confirm with your pharmacist or doctor — especially if you take other medications or have a health condition.

Should I take Sitostanol and Trospium at the same time of day?

At least one FDA label for a product containing Trospium says to take it on an empty stomach, and supplements are usually taken with a meal — so taking them together at breakfast is the easy mistake. Where that applies, keep Trospium on its own and move Sitostanol to a meal later in the day. Food instructions belong to the product rather than the ingredient, so check the directions on your own box. This is about absorption, not an interaction.

Does Trospium interact with any supplements?

Yes. Trospium has documented interactions with 47 supplements in our database — Sitostanol is not one of them. The Trospium interaction page linked on this page lists every one, ranked by severity.

Written and reviewed by the HelloPharmacist editorial staff. Our editorial policy

Where next

Keep Exploring

Sitostanol monograph Uses, safety profile, and every drug interaction in one place Trospium drug information The full plain-English guide to this medication Trospium supplement interactions Every supplement checked against Trospium, ranked by severity Supplement interaction checker Check any supplement or product against your medications Browse medications A–Z Every drug we’ve checked against herbs & supplements References The 26 citations behind this page Ask a pharmacist Free, personal answer from our licensed team

Still Have a Question About Trospium and Sitostanol?

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This information is for education only and is not a substitute for professional medical advice. Always check with your pharmacist or doctor before starting, stopping, or combining supplements and medications.