Cholestyramine

Prescription ·Exploratory record · not publication-reviewed ·Updated July 13, 2026

Cholestyramine is an oral, non-absorbed anion-exchange resin used to lower elevated LDL cholesterol and to relieve pruritus associated with partial biliary obstruction. It binds bile acids in the intestine, forming an insoluble complex that is excreted in the feces, which interrupts the enterohepatic circulation of bile acids. Because it is not absorbed systemically, its effects and adverse events are largely confined to the gastrointestinal tract and to interference with the absorption of other substances.

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Publication status

Exploratory record, not a reviewed medical publication.

See the editorial and medical-review policies for the publication gate.

This generated database record has not completed a claim-level review by a qualified human medical reviewer. Bibliography links and evidence labels are not approval. The page remains available for reference and is excluded from search indexing.

In short

What the research says.

A quick, data-only summary. The full evidence, dosing, and sources are below.

Cholestyramine is an oral, non-absorbed anion-exchange resin used to lower elevated LDL cholesterol and to relieve pruritus associated with partial biliary obstruction. NutriStack rates the supporting evidence as strong. Common adult dosing is Adults: typically 4 g of anhydrous resin once or twice daily initially, titrated to a usual maintenance range of 8 to 16 g per day divided into 2 doses; maximum about 24 g per day. Each dose is mixed with water or other fluid before ingestion (never taken dry)., though a prescriber sets the actual dose. With long-term use it can deplete vitamin d, vitamin k, vitamin a. This profile indexes 3 sources.

What it's good for

Reduction of elevated LDL cholesterol (primary hypercholesterolemia)^1,2
Relief of pruritus associated with partial biliary obstruction and cholestasis^2,1
Adjunct to diet in management of hyperlipidemia
Off-label management of bile acid (cholerheic) diarrhea^2,3

What to watch for

Constipation (very common, may be severe)
Abdominal pain, bloating, and flatulence
Nausea and dyspepsia
Complete biliary obstruction (no bile acids are secreted into the gut, so the drug is ineffective)^2,3
Known hypersensitivity to cholestyramine or any component of the formulation^1,2

The bottom line

Evidence rating strong. Most-documented uses: reduction of elevated ldl cholesterol (primary hypercholesterolemia), relief of pruritus associated with partial biliary obstruction and cholestasis, adjunct to diet in management of hyperlipidemia. 3 sources indexed (1984–2018), with 0 interaction records on file.

The science

How it works, mechanistically.

Core mechanism

Cholestyramine is a quaternary ammonium anion-exchange resin that binds negatively charged bile acids in the intestinal lumen, forming a non-absorbable complex that is eliminated in the stool. The resulting depletion of the bile acid pool removes the normal feedback inhibition of cholesterol 7-alpha-hydroxylase, increasing hepatic conversion of cholesterol into new bile acids. To replenish hepatic cholesterol, the liver upregulates LDL receptors and increases clearance of LDL particles from the circulation, lowering serum LDL cholesterol. By sequestering bile acids it also reduces the micellar solubilization needed for absorption of dietary fat and fat-soluble vitamins, and its resin can adsorb numerous co-administered drugs and luminal substances such as bile-acid-driven irritants that cause cholestatic pruritus.^1,2

Class

Bile acid sequestrant

Absorption

Water-soluble; take with food

Dosing

Dosing & protocol.

Common range

Adults: typically 4 g of anhydrous resin once or twice daily initially, titrated to a usual maintenance range of 8 to 16 g per day divided into 2 doses; maximum about 24 g per day. Each dose is mixed with water or other fluid before ingestion (never taken dry).

Recommended form

Oral powder for suspension (4 g anhydrous resin per packet or scoop), available as regular and sugar-free/light formulations; also as chewable bar in some formulations.

The resin itself is not absorbed from the gastrointestinal tract. It is usually taken with meals (commonly before or with breakfast and the evening meal) because it acts in the gut on bile acids released during digestion. The powder must be mixed thoroughly with at least 60 to 180 mL of water, juice, or other fluid and allowed to hydrate; it should never be taken in dry form due to esophageal irritation and aspiration risk. Critically, cholestyramine binds and reduces absorption of fat-soluble vitamins (A, D, E, K), folic acid, and many co-administered oral drugs, so other medications should generally be taken at least 1 hour before or 4 to 6 hours after cholestyramine.³

Depletions

What it depletes.

Nutrients this medication can lower over time, and what to replace.

Vitamin D

Moderate

Bile acid sequestration can impair absorption of fat-soluble vitamin D.

Replace Vitamin D3Monitor 25-hydroxyvitamin DOnset Months with chronic therapy

Vitamin K

Significant

Bile acid sequestration can impair vitamin K absorption and lower vitamin K dependent clotting factor activity.

Replace Vitamin K1Monitor Prothrombin time/INROnset Weeks to months in susceptible patients

Vitamin A

Moderate

Bile acid sequestration can impair absorption of fat-soluble vitamin A during long-term use.

Replace Vitamin A if prescribedMonitor Serum retinol if deficiency suspectedOnset Months with chronic therapy

Vitamin E

Moderate

Bile acid sequestration can impair absorption of fat-soluble vitamin E during long-term use.

Replace Vitamin EMonitor Alpha-tocopherol if deficiency suspectedOnset Months with chronic therapy

Folate

Mild

Cholestyramine can bind folate in the gut and lower its absorption; reduced serum and red-cell folate has been reported with prolonged therapy, with the greatest concern in children, pregnant patients, and those with marginal intake.

Replace Folic acid, taken at least 1 hour before or 4 to 6 hours after cholestyramineMonitor Serum folate and red-blood-cell folateOnset Months of continuous therapy

Full Cholestyramine depletion and interaction guide →

Safety

Full safety detail.

Side effects

Constipation (very common, may be severe)
Abdominal pain, bloating, and flatulence
Nausea and dyspepsia
Heartburn and esophageal irritation
Steatorrhea and reduced absorption of dietary fat with high doses
Deficiency of fat-soluble vitamins A, D, E, and K with prolonged or high-dose use
Hypoprothrombinemia and increased bleeding tendency from vitamin K depletion
Folic acid deficiency (relevant in children and pregnancy)
Hyperchloremic metabolic acidosis (particularly in children and at high doses)
Reduced absorption and efficacy of many co-administered oral drugs

Contraindications

Complete biliary obstruction (no bile acids are secreted into the gut, so the drug is ineffective)^2,3
Known hypersensitivity to cholestyramine or any component of the formulation^1,2
Caution with phenylketonuria for formulations containing aspartame (sugar-free/light products)
Relative caution in pre-existing constipation, hemorrhoids, or conditions worsened by constipation
Caution in patients prone to hyperchloremic acidosis and in young children

Sources

Sources, by evidence tier.

Numbered references. Citations throughout the page link here.

Randomized controlled trials

1The Lipid Research Clinics Coronary Primary Prevention Trial results. I. Reduction in incidence of coronary heart diseasePMIDLipid Research Clinics Program · JAMA · 1984
Cholestyramine reduced total cholesterol and LDL cholesterol and was associated with a significant reduction in coronary heart disease death and nonfatal myocardial infarction compared with placebo.

Reviews & position papers

2Questran (cholestyramine for oral suspension) FDA prescribing informationBristol-Myers Squibb · FDA label · 2018
Label describes mechanism, indications for primary hypercholesterolemia and pruritus of partial biliary obstruction, and warnings regarding fat-soluble vitamin malabsorption and drug interactions.
3Bile acid sequestrants: a review of mechanism of action and clinical usePMIDInsull W · Southern Medical Journal · 2006
Bile acid sequestrants reduce LDL cholesterol but interfere with absorption of fat-soluble vitamins and numerous drugs; co-administered medications should be dosed 1 hour before or 4 to 6 hours after the sequestrant.

FAQ

Common questions.

Quick answers about Cholestyramine, drawn from the data on this page.

What is Cholestyramine?

What is Cholestyramine used for?

Commonly cited benefits of Cholestyramine include: Reduction of elevated LDL cholesterol (primary hypercholesterolemia); Relief of pruritus associated with partial biliary obstruction and cholestasis; Adjunct to diet in management of hyperlipidemia; Off-label management of bile acid (cholerheic) diarrhea. NutriStack rates the overall evidence as strong.

What is a typical dose of Cholestyramine?

A typical adult dose of Cholestyramine is Adults: typically 4 g of anhydrous resin once or twice daily initially, titrated to a usual maintenance range of 8 to 16 g per day divided into 2 doses; maximum about 24 g per day. Each dose is mixed with water or other fluid before ingestion (never taken dry).. The commonly recommended form is Oral powder for suspension (4 g anhydrous resin per packet or scoop), available as regular and sugar-free/light formulations; also as chewable bar in some formulations.. These are general ranges, not personalized advice; confirm the right dose with a clinician.

What are the side effects of Cholestyramine?

Reported side effects include constipation (very common, may be severe), abdominal pain, bloating, and flatulence, nausea and dyspepsia, heartburn and esophageal irritation, steatorrhea and reduced absorption of dietary fat with high doses, deficiency of fat-soluble vitamins a, d, e, and k with prolonged or high-dose use. This is educational information; check with a healthcare professional before use.

How strong is the evidence for Cholestyramine?

NutriStack rates this as Strong, meaning multiple high-quality meta-analyses or systematic reviews converge on the same finding. Full tier criteria are at https://nutristackapp.com/methodology/evidence-tiers.

Use this with your stack

Cholestyramine in NutriStack.

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