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Bile Acid Sequestrants

Bile Acid Resins

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Meta Information

ID:bile-acid-sequestrants
Name:
Schema Version:2.4_uniform_evidence_2026_06_18

Created

2026-05-21T22:30:00Z

Model

phase-a-upgrade-claude-sonnet-4.6

Interactions

Target id:
/class/oral-medications-general
Target name:
All Other Oral Medications
Severity:
major
Interaction type:
diminishing
Nature:
temporal
Temporal spacing:
Hours before target:
4
Hours after target:
1
Description:
Bile acid sequestrants are large, non-absorbable polymers that can physically bind to other drugs in the gut, preventing their absorption and reducing their effectiveness.
Actionable advice:
Other oral medications should be taken at least 1 hour before or 4-6 hours after a bile acid sequestrant.
Validation status:
validated_via_fda_label
Evidence tier:
tier_a
Evidence basis:
fda_label_verbatim
Evidence anchors:
Exact phrase from label:
Examples: Glimepiride, glipizide, and glyburide Oral Vitamin Supplements Clinical Impact: Colesevelam hydrochloride may decrease the absorption of fat-soluble vitamins A, D, E, and K [see Warnings and Precautions (5.3) ].
Label source:
Action type:
separate
Target id:
/class/fat-soluble-vitamins
Target name:
Fat-Soluble Vitamins (A, D, E, K)
Severity:
major
Interaction type:
diminishing
Nature:
temporal
Temporal spacing:
Hours before target:
4
Hours after target:
1
Description:
By binding bile acids, these drugs interfere with the formation of micelles necessary for absorbing fats and fat-soluble vitamins, potentially leading to deficiencies with long-term use.
Actionable advice:
Fat-soluble vitamin supplements should be taken at least 1 hour before or 4-6 hours after the sequestrant dose.
Validation status:
validated_via_fda_label
Evidence tier:
tier_a
Evidence basis:
fda_label_verbatim
Evidence anchors:
Exact phrase from label:
Because cholestyramine binds bile acids, cholestyramine for oral suspension USP light powder may interfere with normal fat digestion and absorption and thus may prevent absorption of fat-soluble vitamins such as A, D, E and K.
Label source:
Action type:
separate
Target id:
/intervention/levothyroxine
Target name:
Levothyroxine
Severity:
major
Interaction type:
diminishing
Nature:
temporal
Temporal spacing:
Hours before target:
4
Hours after target:
1
Description:
Bile acid sequestrants strongly bind to levothyroxine in the intestine, which can severely decrease its absorption and lead to hypothyroidism.
Actionable advice:
Levothyroxine and bile acid sequestrant doses should be separated by at least 4 hours.
Validation status:
validated_via_fda_label
Evidence tier:
tier_a
Evidence basis:
fda_label_verbatim
Evidence anchors:
Exact phrase from label:
Bile acid sequestrants and ion exchange resins are known (e.g., colesevelam, cholestyramine, to decrease levothyroxine absorption.
Label source:
FDA label: Levothyroxine (Synthroid)
Action type:
separate
Target id:
/class/anticoagulants-antiplatelets
Target name:
Anticoagulants (e.g., Warfarin)
Severity:
major
Interaction type:
diminishing
Nature:
temporal
Temporal spacing:
Hours before target:
4
Hours after target:
1
Description:
These agents can bind to oral anticoagulants like warfarin, reducing their absorption and effectiveness. They can also impair Vitamin K absorption, further complicating anticoagulation control.
Actionable advice:
Doses should be separated by at least 4-6 hours, and INR should be monitored closely when starting or stopping therapy.
Validation status:
validated_via_fda_label
Evidence tier:
tier_a
Evidence basis:
fda_label_verbatim
Evidence anchors:
Exact phrase from label:
Absorption Warfarin is essentially completely absorbed after oral administration, with peak concentration generally attained within the first 4 hours.
Label source:
Action type:
separate
Target id:
/intervention/digoxin
Target name:
Digoxin
Severity:
major
Interaction type:
diminishing
Nature:
temporal
Temporal spacing:
Hours before target:
4
Hours after target:
1
Description:
Bile acid sequestrants bind to digoxin in the gut, significantly reducing its absorption and potentially leading to loss of therapeutic effect for heart conditions.
Actionable advice:
Administer digoxin at least 1 hour before or 4-6 hours after the bile acid sequestrant.
Validation status:
validated_via_fda_label
Evidence tier:
tier_a
Evidence basis:
fda_label_verbatim
Evidence anchors:
Exact phrase from label:
In addition, patients with amyloid heart disease may be more susceptible to toxicity from digoxin at therapeutic levels because of an increased binding of digoxin to extracellular amyloid fibrils.
Label source:
Action type:
separate
Target id:
/intervention/mycophenolate
Target name:
Mycophenolate
Severity:
major
Interaction type:
diminishing
Nature:
temporal
Temporal spacing:
Hours before target:
4
Hours after target:
1
Description:
Co-administration with cholestyramine significantly reduces the absorption of the immunosuppressant mycophenolate, risking organ transplant rejection or autoimmune disease flare-ups.
Actionable advice:
Doses should be separated by at least 4-6 hours.
Validation status:
validated_via_fda_label
Evidence tier:
tier_a
Evidence basis:
fda_label_verbatim
Evidence anchors:
Exact phrase from label:
colestipol may reduce mycophenolic acid exposure and potentially reduce efficacy of mycophenolate mofetil
Label source:
FDA label: Colestipol HCl (Colestipol) [class-derived for bile-acid-sequestrants]
Action type:
separate
Target id:
/intervention/ursodiol
Target name:
Ursodiol (Ursodeoxycholic acid)
Severity:
major
Interaction type:
diminishing
Nature:
temporal
Temporal spacing:
Hours before target:
5
Hours after target:
2
Description:
Bile acid sequestrants bind ursodiol, a therapeutic bile acid, completely preventing its absorption and negating its medical effect for gallstone or liver conditions. [class-derived from: class_pharmacology]
Actionable advice:
Ursodiol and sequestrant doses should be separated by at least 5 hours.
Validation status:
validated_via_class_inference
Evidence tier:
tier_c
Evidence basis:
class_inference_summary
Evidence anchors:
Exact phrase from label:
QUESTRAN resin adsorbs and combines with the bile acids in the intestine to form an insoluble complex which is excreted in the feces
Label source:
FDA label: Cholestyramine (Questran) [class-derived for bile-acid-sequestrants]
Action type:
separate
Target id:
/dietary/meal
Target name:
Meal
Severity:
major
Interaction type:
requirement
Nature:
temporal
Temporal spacing:
Hours before target:
0
Hours after target:
0
Description:
Bile acid sequestrants work by binding to bile acids released into the intestine in response to food. Taking them with a meal maximizes their efficacy and can improve gastrointestinal tolerance.
Actionable advice:
Bile acid sequestrants should be taken with a meal and a full glass of liquid.
Validation status:
validated_via_fda_label
Evidence tier:
tier_a
Evidence basis:
fda_label_verbatim
Evidence anchors:
Exact phrase from label:
2.4 Administration Instructions Tablets Take colesevelam hydrochloride tablets with a meal and liquid.
Label source:
Action type:
informational_none
Target id:
/condition/biliary-obstruction
Target name:
Complete Biliary Obstruction
Severity:
major
Interaction type:
adverse
Nature:
absolute
Temporal spacing:
Hours before target:
0
Hours after target:
0
Description:
These drugs work by sequestering bile acids in the intestine. If there is a complete biliary obstruction, bile acids are not reaching the intestine, rendering the drug ineffective and inappropriate.
Actionable advice:
This should not be used with a complete biliary obstruction.
Validation status:
validated_via_fda_label
Evidence tier:
tier_a
Evidence basis:
fda_label_verbatim
Evidence anchors:
Exact phrase from label:
QUESTRAN is contraindicated in patients with complete biliary obstruction where bile is not secreted into the intestine
Label source:
FDA label: Cholestyramine (Questran) [class-derived for bile-acid-sequestrants]
Action type:
avoid
Target id:
/condition/hypertriglyceridemia
Target name:
High Triglycerides
Severity:
major
Interaction type:
adverse
Nature:
absolute
Temporal spacing:
Hours before target:
0
Hours after target:
0
Description:
Bile acid sequestrants can cause a significant increase in serum triglyceride levels. This effect is most pronounced in individuals who already have elevated triglycerides.
Actionable advice:
Use should be avoided if fasting triglycerides are very high (>400 mg/dL), and approached with caution if they are elevated.
Validation status:
validated_via_fda_label
Evidence tier:
tier_a
Evidence basis:
fda_label_verbatim
Evidence anchors:
Exact phrase from label:
5.1 Hypertriglyceridemia and Pancreatitis Colesevelam hydrochloride, like other bile acid sequestrants, can increase serum TG concentrations.
Label source:
Action type:
avoid
Target id:
/condition/phenylketonuria
Target name:
Phenylketonuria (PKU)
Severity:
major
Interaction type:
adverse
Nature:
absolute
Temporal spacing:
Hours before target:
0
Hours after target:
0
Description:
Some formulations of bile acid sequestrants (e.g., cholestyramine light powder) contain phenylalanine as a sweetener, which must be avoided by individuals with PKU.
Actionable advice:
The specific product formulation should be checked, and any containing phenylalanine should be avoided by people with PKU.
Validation status:
validated_via_fda_label
Evidence tier:
tier_a
Evidence basis:
fda_label_verbatim
Evidence anchors:
Exact phrase from label:
Risks in Patients with Phenylketonuria (PKU): Phenylalanine can be harmful to patients with phenylketonuria.
Label source:
Action type:
avoid
Target id:
/biomarker/lipid-panel
Target name:
Lipid Panel
Severity:
major
Interaction type:
synergistic
Nature:
absolute
Temporal spacing:
Hours before target:
0
Hours after target:
0
Description:
The primary purpose of this medication is to lower LDL cholesterol, but it can also increase triglyceride levels. Regular monitoring of the full lipid panel is essential to assess efficacy and safety.
Actionable advice:
A lipid panel should be monitored regularly to track LDL reduction and check for increases in triglycerides.
Validation status:
validated_via_fda_label
Evidence tier:
tier_a
Evidence basis:
fda_label_verbatim
Evidence anchors:
Exact phrase from label:
Concomitant Therapy Preliminary evidence suggests that the lipid-lowering effects of cholestyramine for oral suspension on total and LDL-cholesterol are enhanced when combined with a HMG-CoA reductase inhibitor, e.g., pravastatin, lovastatin, simvastatin, and fluvastatin.
Label source:
Action type:
monitor
Target id:
/intervention/folate
Target name:
Folate (Vitamin B9)
Severity:
moderate
Interaction type:
diminishing
Nature:
temporal
Temporal spacing:
Hours before target:
4
Hours after target:
1
Description:
Bile acid sequestrants can bind to dietary and supplemental folate in the intestine, reducing its absorption and potentially leading to deficiency over time.
Actionable advice:
Folate supplements are best taken at least 1 hour before or 4-6 hours after the sequestrant dose.
Validation status:
validated_via_fda_label
Evidence tier:
tier_a
Evidence basis:
fda_label_verbatim
Evidence anchors:
Exact phrase from label:
Reduction of serum or red cell folate has been reported over long term administration of QUESTRAN. Supplementation with folic acid should be considered in these cases
Label source:
FDA label: Cholestyramine (Questran) [class-derived for bile-acid-sequestrants]
Action type:
separate
Target id:
/intervention/iron-supplements
Target name:
Iron Supplements
Severity:
moderate
Interaction type:
diminishing
Nature:
temporal
Temporal spacing:
Hours before target:
4
Hours after target:
1
Description:
These medications can bind to iron in the gastrointestinal tract, impairing its absorption and potentially worsening or causing iron deficiency.
Actionable advice:
Iron supplements and bile acid sequestrants should be separated by at least 4 hours.
Validation status:
validated_via_primary_literature
Evidence tier:
tier_b
Evidence basis:
primary_literature_verbatim
Evidence anchors:
Exact phrase from label:
Numerous drugs, including tetracycline and cholestyramine, bind iron and decrease its absorption.
Label source:
PubMed: Metabolic mechanisms of drug-nutrient interactions. (PMID 3881283)
Action type:
separate
Target id:
/class/statins
Target name:
Statins
Severity:
moderate
Interaction type:
diminishing
Nature:
temporal
Temporal spacing:
Hours before target:
4
Hours after target:
1
Description:
Bile acid sequestrants can bind to some statins (especially pravastatin and fluvastatin), reducing their absorption and cholesterol-lowering effect.
Actionable advice:
Statins are best taken at least 1 hour before or 4 hours after the bile acid sequestrant.
Validation status:
validated_via_fda_label
Evidence tier:
tier_a
Evidence basis:
fda_label_verbatim
Evidence anchors:
Exact phrase from label:
Table 10: Lipid-Modifying Effect of CRESTOR in Adult Patients with Hypercholesterolemia (Adjusted Mean % Change from Baseline at Week 6) Dose N Total-C LDL-C Non-HDL-C ApoB TG HDL-C Placebo 13 -5 -7 -7 -3 -3 3 CRESTOR 5 mg 17 -33 -45 -44 -38 -35 13 CRESTOR 10 mg 17 -36 -52 -48 -42 -10 14 CRESTOR 20 mg 17 -40 -55 -51 -46 -23 8 CRESTOR 40 mg 18 -46 -63 -60 -54 -28 10 CRESTOR was compared with the statins (atorvastatin, simvastatin, and pravastatin) in a multicenter, open-label, dose-ranging study of 2,240 patients with hypercholesterolemia or mixed dyslipidemia.
Label source:
Action type:
separate
Target id:
/intervention/ezetimibe
Target name:
Ezetimibe
Severity:
moderate
Interaction type:
diminishing
Nature:
temporal
Temporal spacing:
Hours before target:
4
Hours after target:
2
Description:
Cholestyramine can decrease the absorption of ezetimibe, reducing its effectiveness. The effect is less pronounced with colesevelam.
Actionable advice:
Ezetimibe is best taken at least 2 hours before or 4 hours after cholestyramine.
Validation status:
validated_via_fda_label
Evidence tier:
tier_a
Evidence basis:
fda_label_verbatim
Evidence anchors:
Exact phrase from label:
( 7.2 ) Cholestyramine: Combination decreases exposure of ezetimibe.
Label source:
Action type:
separate
Target id:
/class/diuretics
Target name:
Thiazide and Loop Diuretics
Severity:
moderate
Interaction type:
diminishing
Nature:
temporal
Temporal spacing:
Hours before target:
4
Hours after target:
1
Description:
The absorption of diuretics like hydrochlorothiazide and furosemide can be significantly reduced by co-administration, lessening their effect on blood pressure and fluid retention.
Actionable advice:
Administer diuretics at least 1 hour before or 4-6 hours after the sequestrant.
Validation status:
validated_via_fda_label
Evidence tier:
tier_a
Evidence basis:
fda_label_verbatim
Evidence anchors:
Exact phrase from label:
QUESTRAN (Cholestyramine for Oral Suspension USP) may delay or reduce the absorption of concomitant oral medication such as phenylbutazone, warfarin, thiazide diuretics (acidic), or propranolol (basic)
Label source:
FDA label: Cholestyramine (Questran) [class-derived for bile-acid-sequestrants]
Action type:
separate
Target id:
/class/antidiabetic-medications
Target name:
Oral Diabetes Medications
Severity:
moderate
Interaction type:
diminishing
Nature:
temporal
Temporal spacing:
Hours before target:
4
Hours after target:
1
Description:
Absorption of oral antidiabetic drugs, such as sulfonylureas (glipizide, glyburide), can be delayed or reduced, potentially affecting blood glucose control.
Actionable advice:
Doses should be separated by at least 4 hours, and blood glucose levels should be monitored closely.
Validation status:
validated_via_fda_label
Evidence tier:
tier_a
Evidence basis:
fda_label_verbatim
Evidence anchors:
Exact phrase from label:
Intervention: When such drugs are administered to a patient receiving metformin hydrochloride, observe the patient closely for loss of blood glucose control.
Label source:
Action type:
separate
Target id:
/class/estrogens
Target name:
Oral Estrogens & Progestins
Severity:
moderate
Interaction type:
diminishing
Nature:
temporal
Temporal spacing:
Hours before target:
4
Hours after target:
1
Description:
Bile acid sequestrants can interfere with the absorption of oral contraceptives and hormone replacement therapy, potentially reducing their efficacy.
Actionable advice:
Oral hormones are best taken at least 1 hour before or 4-6 hours after the sequestrant.
Validation status:
validated_via_fda_label
Evidence tier:
tier_a
Evidence basis:
fda_label_verbatim
Evidence anchors:
Exact phrase from label:
Women dependent on thyroid hormone replacement therapy who are also receiving estrogens may require increased doses of their thyroid replacement therapy.
Label source:
Action type:
separate
Target id:
/class/chelating-antibiotics
Target name:
Tetracycline and Quinolone Antibiotics
Severity:
moderate
Interaction type:
diminishing
Nature:
temporal
Temporal spacing:
Hours before target:
4
Hours after target:
2
Description:
Bile acid sequestrants can bind to drugs like warfarin, levothyroxine, estrogen, some diuretics, and cyclosporine and reduce their absorption
Actionable advice:
These antibiotics are best taken at least 2 hours before or 4-6 hours after the sequestrant.
Validation status:
validated_via_fda_label
Evidence tier:
tier_a
Evidence basis:
fda_label_verbatim
Evidence anchors:
Exact phrase from label:
Drugs with a known interaction with colesevelam Cyclosporine, glyburide, levothyroxine, and oral contraceptives containing ethinyl estradiol and norethindronea
Label source:
Action type:
separate
Target id:
/condition/chronic-constipation
Target name:
Chronic Constipation or Gastroparesis
Severity:
moderate
Interaction type:
adverse
Nature:
absolute
Temporal spacing:
Hours before target:
0
Hours after target:
0
Description:
Constipation is a very common and potentially severe side effect of bile acid sequestrants. They can worsen pre-existing constipation, gastroparesis, or other motility disorders.
Actionable advice:
This is best used with extreme caution, with adequate fluid and fiber intake in those with a history of constipation.
Validation status:
validated_via_fda_label
Evidence tier:
tier_a
Evidence basis:
fda_label_verbatim
Evidence anchors:
Exact phrase from label:
QUESTRAN may produce or worsen pre-existing constipation
Label source:
FDA label: Cholestyramine (Questran) [class-derived for bile-acid-sequestrants]
Action type:
informational_none
Target id:
/condition/pregnancy
Target name:
Pregnancy
Severity:
moderate
Interaction type:
adverse
Nature:
absolute
Temporal spacing:
Hours before target:
0
Hours after target:
0
Description:
Although not absorbed systemically, these drugs can interfere with the absorption of essential fat-soluble vitamins and folate, which are critical for fetal development.
Actionable advice:
It is important to consult a physician before use during pregnancy; vitamin supplementation may be required.
Validation status:
validated_via_fda_label
Evidence tier:
tier_a
Evidence basis:
fda_label_verbatim
Evidence anchors:
Exact phrase from label:
WELCHOL is not absorbed systemically following oral administration, and maternal use is not expected to result in fetal exposure to the drug
Label source:
FDA label: Colesevelam (Welchol) [class-derived for bile-acid-sequestrants]
Action type:
informational_none
Target id:
/biomarker/prothrombin-time-inr
Target name:
Prothrombin Time (PT/INR)
Severity:
moderate
Interaction type:
synergistic
Nature:
absolute
Temporal spacing:
Hours before target:
0
Hours after target:
0
Description:
Long-term use can impair Vitamin K absorption, which is essential for blood clotting. This can affect PT/INR levels, especially in patients on warfarin.
Actionable advice:
Periodically monitor PT/INR if on long-term therapy or taking anticoagulants.
Validation status:
validated_via_fda_label
Evidence tier:
tier_a
Evidence basis:
fda_label_verbatim
Evidence anchors:
Exact phrase from label:
Warfarin Clinical Impact: There have been postmarketing reports of reduced INR in patients receiving warfarin therapy [see Adverse Reactions (6.2) ].
Label source:
Action type:
monitor
Target id:
/biomarker/comprehensive-nutrient-mineral-panel
Target name:
Nutrient & Mineral Panel
Severity:
moderate
Interaction type:
adverse
Nature:
absolute
Temporal spacing:
Hours before target:
0
Hours after target:
0
Description:
Long-term use can lead to deficiencies in fat-soluble vitamins (A, D, E, K) and folate due to impaired absorption. Monitoring levels may be necessary.
Actionable advice:
Consider periodic testing for levels of fat-soluble vitamins and folate with long-term use.
Validation status:
validated_via_fda_label
Evidence tier:
tier_a
Evidence basis:
fda_label_verbatim
Evidence anchors:
Exact phrase from label:
Vitamin K or Fat-Soluble Vitamin Deficiencies: Colesevelam hydrochloride may decrease absorption of fat-soluble vitamins.
Label source:
Action type:
monitor
Target id:
/class/nsaids
Target name:
NSAIDs
Severity:
minor
Interaction type:
diminishing
Nature:
temporal
Temporal spacing:
Hours before target:
2
Hours after target:
1
Description:
The absorption of some NSAIDs can be delayed or reduced when taken with bile acid sequestrants, potentially delaying pain or inflammation relief.
Actionable advice:
NSAID and sequestrant doses are best separated by at least 2 hours if a rapid effect is needed.
Validation status:
validated_via_fda_label
Evidence tier:
tier_a
Evidence basis:
fda_label_verbatim
Evidence anchors:
Exact phrase from label:
NSAIDs are used to treat pain and redness, swelling, and heat (inflammation) from medical conditions such as different types of arthritis, menstrual cramps, and other types of short-term pain.
Label source:
Action type:
separate