Cholestyramine side effects: what 12,017 FDA adverse event reports show

Cholestyramine · 1,145 reaction terms · 53,523 drug–reaction co-reports · data 2026-09-14

Drug class

Bile Acid Sequestrant

FDA label (Established Pharmacologic Class)

Who reports

12,017 reports · 67% serious · 834 with death outcome · 63% female

openFDA FAERS counts, all years, deduplication not applied

Used for

1) Cholestyramine for oral suspension is indicated as adjunctive therapy to diet for the reduction of elevated serum cholesterol in patients with primary hypercholesterolemia (elevated low density lipoprotein [LDL] cholesterol) who do not respond adequately to diet.

FDA label, Indications and Usage

What it is

DESCRIPTION Cholestyramine for oral suspension USP, the chloride salt of a basic anion exchange resin, a cholesterol lowering agent, is intended for oral administration. Cholestyramine resin, USP is quite hydrophilic, but insoluble in water.

FDA label, Description section

Boxed warning

None in the current label

How to read this page. FAERS is a spontaneous-reporting system: counts are not incidence rates and a signal is not proof of causation. Each reaction below is run through an automated screen — is the term in the FDA label (known), in the indications (the disease being treated), an administrative/coding term, or none of these (unlabeled)? That screen is mechanical text matching, not a causality assessment. The 30 hand-written Bradford Hill assessments are on the causality assessment page. Not medical advice.

Causality screen of the 40 strongest signals

Reporting / coding artifact 6Lab value / disease marker 6Not in label — unassessed 28

What the badges mean

Reporting / coding artifact An administrative, monitoring or exposure term (product issue, off-label use, 'test normal', overdose...). Not a biological reaction; a high PRR here reflects how reports are coded.
Lab value / disease marker A laboratory result, investigation or disease-activity marker (antibody positive, CRP abnormal, swollen joint count) not described in the label. These usually mirror the monitored disease or testing protocol rather than a drug effect; not screened further.
Not in label — unassessed Not found in the label text, not an artifact pattern. This is a genuine candidate for a formal causality assessment (Bradford Hill / WHO-UMC); it has NOT had one here.

Strongest disproportionality signals

Flagged terms (PRR ≥ 2, χ² ≥ 4, n ≥ 10), ranked by PRR; infinite PRRs (no comparator reports) excluded. The EBGM column is a second, shrinkage-based estimate (MGPS) with its 5th percentile EB05 and the BCPNN IC025; a pair flagged by PRR alone is marked PRR-only and should be read as fragile. The strata column recomputes the PRR on serious reports only and flags pairs whose reports are unusually skewed by sex or come mostly from consumers rather than clinicians. 1,105 further terms are in the interactive explorer. Reaction links open the term's cross-drug page.

Show: hide coding/lab/outcome terms hide indication terms unlabeled only hide PRR-only

Reaction	Reports	PRR 95% CI · ROR · χ²/p	EBGM EB05 · IC025	Label screen	Serious-only & strata	Trial cross-check
Intestinal intraepithelial lymphocytes increased	13	438.5 238.6–806.0ROR 439.0 · χ² 4,180 / p <1e-300	231.2 EB05 143.8 · IC025 +3.7 3/3 methods agree	Lab value / disease marker	serious n=13	no trial arm names this drug
Microvillous inclusion disease	13	360.7 198.4–655.7ROR 361.1 · χ² 3,563 / p <1e-300	207.7 EB05 129.2 · IC025 +3.7 3/3 methods agree	Not in label — unassessed	serious n=13	no trial arm names this drug
Pulmonary interstitial emphysema syndrome	19	267.9 165.3–434.3ROR 268.4 · χ² 4,144 / p <1e-300	188.3 EB05 127.4 · IC025 +4.3 3/3 methods agree	Not in label — unassessed	serious n=19	no trial arm names this drug
Alveolar lung disease	20	203.6 128.1–323.5ROR 203.9 · χ² 3,426 / p <1e-300	155.4 EB05 106.2 · IC025 +4.3 3/3 methods agree	Not in label — unassessed	serious n=20	no trial arm names this drug
Probiotic therapy	10	197.7 102.8–380.4ROR 197.9 · χ² 1,584 / p <1e-300	133.1 EB05 77.2 · IC025 +3.2 3/3 methods agree	Reporting / coding artifact	serious n=10	no trial arm names this drug
Cryptitis	13	178.9 101.1–316.7ROR 179.1 · χ² 1,925 / p <1e-300	131.4 EB05 81.7 · IC025 +3.6 3/3 methods agree	Not in label — unassessed	serious n=13	no trial arm names this drug
Bile acid malabsorption	23	160.2 104.5–245.5ROR 160.5 · χ² 3,185 / p <1e-300	130.9 EB05 91.9 · IC025 +4.5 3/3 methods agree	Not in label — unassessed	serious n=21	no trial arm names this drug
Apoptosis	14	81.9 47.9–140.0ROR 82.0 · χ² 992 / p 4e-218	71.0 EB05 44.9 · IC025 +3.5 3/3 methods agree	Not in label — unassessed	serious n=14	no trial arm names this drug
Product solubility abnormal	179	64.8 55.9–75.2ROR 65.8 · χ² 10,784 / p <1e-300	62.1 EB05 54.9 · IC025 +5.5 3/3 methods agree	Reporting / coding artifact	serious n=9 · 85% consumer	no trial arm names this drug
Laparotomy	13	51.1 29.4–88.6ROR 51.1 · χ² 572 / p 1e-126	46.5 EB05 28.9 · IC025 +3.2 3/3 methods agree	Not in label — unassessed	serious n=13	no trial arm names this drug
Post procedural diarrhoea	14	49.4 29.0–83.9ROR 49.4 · χ² 599 / p 2e-132	45.3 EB05 28.7 · IC025 +3.3 3/3 methods agree	Reporting / coding artifact	serious n=14	no trial arm names this drug
Short-bowel syndrome	17	46.7 28.9–75.6ROR 46.8 · χ² 697 / p 8e-154	43.5 EB05 28.7 · IC025 +3.5 3/3 methods agree	Not in label — unassessed	serious n=17	no trial arm names this drug
Anastomotic ulcer	11	42.9 23.6–78.0ROR 43.0 · χ² 399 / p 4e-89	39.3 EB05 23.4 · IC025 +2.9 3/3 methods agree	Not in label — unassessed	serious n=11	no trial arm names this drug
Product physical consistency issue	131	42.8 36.0–50.9ROR 43.3 · χ² 5,178 / p <1e-300	41.5 EB05 35.9 · IC025 +4.9 3/3 methods agree	Reporting / coding artifact	82% consumer	no trial arm names this drug
Intestinal anastomosis	15	42.7 25.6–71.2ROR 42.7 · χ² 555 / p 4e-123	39.7 EB05 25.5 · IC025 +3.3 3/3 methods agree	Not in label — unassessed	serious n=15	no trial arm names this drug
Gastrointestinal stoma output increased	11	42.4 23.3–77.2ROR 42.5 · χ² 395 / p 4e-88	38.9 EB05 23.1 · IC025 +2.9 3/3 methods agree	Lab value / disease marker	serious n=11	no trial arm names this drug
Terminal ileitis	14	41.5 24.4–70.4ROR 41.5 · χ² 501 / p 3e-111	38.6 EB05 24.4 · IC025 +3.2 3/3 methods agree	Not in label — unassessed	serious n=14	no trial arm names this drug
Faecal volume decreased	10	36.8 19.7–68.9ROR 36.9 · χ² 307 / p 5e-69	33.9 EB05 19.6 · IC025 +2.7 3/3 methods agree	Lab value / disease marker	serious n=10	no trial arm names this drug
Thyrotoxic crisis	22	34.6 22.7–52.7ROR 34.7 · χ² 671 / p 3e-148	33.1 EB05 23.0 · IC025 +3.6 3/3 methods agree	Not in label — unassessed	serious n=22 · 100% clinician	no trial arm names this drug
Faecal calprotectin increased	55	31.3 24.0–40.9ROR 31.4 · χ² 1,556 / p <1e-300	30.5 EB05 24.3 · IC025 +4.2 3/3 methods agree	Not in label — unassessed	serious n=54	no trial arm names this drug
Gastrointestinal wall thickening	26	31.1 21.1–45.8ROR 31.1 · χ² 714 / p 1e-157	29.9 EB05 21.5 · IC025 +3.6 3/3 methods agree	Not in label — unassessed	serious n=26 · ♀ 86% (drug 63%)	no trial arm names this drug
Diffuse alveolar damage	20	30.7 19.8–47.8ROR 30.8 · χ² 537 / p 5e-119	29.5 EB05 20.1 · IC025 +3.4 3/3 methods agree	Not in label — unassessed	serious n=20	no trial arm names this drug
Erosive duodenitis	13	28.9 16.7–49.9ROR 28.9 · χ² 317 / p 3e-71	27.4 EB05 16.9 · IC025 +2.9 3/3 methods agree	Not in label — unassessed	serious n=13	no trial arm names this drug
Stoma complication	15	26.0 15.6–43.3ROR 26.0 · χ² 331 / p 3e-74	24.9 EB05 15.9 · IC025 +3.0 3/3 methods agree	Reporting / coding artifact	serious n=15	no trial arm names this drug
Therapeutic reaction time decreased	41	24.6 18.1–33.5ROR 24.7 · χ² 894 / p 1e-196	24.1 EB05 18.5 · IC025 +3.7 3/3 methods agree	Lab value / disease marker	serious n=41	no trial arm names this drug
Ileal stenosis	22	21.8 14.3–33.2ROR 21.9 · χ² 412 / p 8e-92	21.2 EB05 14.7 · IC025 +3.2 3/3 methods agree	Not in label — unassessed	serious n=22	no trial arm names this drug
Small intestinal stenosis	13	21.6 12.5–37.3ROR 21.6 · χ² 232 / p 1e-52	20.5 EB05 12.4 · IC025 +2.7 3/3 methods agree	Not in label — unassessed	serious n=12	no trial arm names this drug
Foetal heart rate abnormal	11	21.0 11.6–38.0ROR 21.0 · χ² 187 / p 6e-43	19.7 EB05 11.1 · IC025 +2.5 3/3 methods agree	Lab value / disease marker	serious n=11	no trial arm names this drug
Foreign body in throat	36	20.9 15.1–29.0ROR 21.0 · χ² 655 / p 1e-144	20.5 EB05 15.4 · IC025 +3.5 3/3 methods agree	Not in label — unassessed	86% consumer	no trial arm names this drug
Product taste abnormal	157	20.6 17.6–24.1ROR 20.9 · χ² 2,875 / p <1e-300	20.3 EB05 17.8 · IC025 +4.0 3/3 methods agree	Reporting / coding artifact	serious n=9 · 81% consumer	no trial arm names this drug
Enterocutaneous fistula	10	20.1 10.8–37.5ROR 20.1 · χ² 161 / p 3e-37	18.7 EB05 9.9 · IC025 +2.3 3/3 methods agree	Not in label — unassessed	serious n=10	no trial arm names this drug
Vascular device infection	51	19.9 15.1–26.2ROR 20.0 · χ² 887 / p 3e-195	19.6 EB05 15.4 · IC025 +3.6 3/3 methods agree	Not in label — unassessed	serious n=51	no trial arm names this drug
Cholangitis sclerosing	23	19.7 13.0–29.6ROR 19.7 · χ² 384 / p 7e-86	19.1 EB05 13.3 · IC025 +3.1 3/3 methods agree	Not in label — unassessed	serious n=22	no trial arm names this drug
Mesenteric vein thrombosis	11	19.4 10.7–35.1ROR 19.4 · χ² 172 / p 2e-39	18.1 EB05 10.0 · IC025 +2.4 3/3 methods agree	Not in label — unassessed	serious n=11	no trial arm names this drug
Intestinal stenosis	46	19.3 14.4–25.7ROR 19.3 · χ² 770 / p 9e-170	18.9 EB05 14.7 · IC025 +3.5 3/3 methods agree	Not in label — unassessed	serious n=46	no trial arm names this drug
Biopsy	10	19.0 10.2–35.4ROR 19.0 · χ² 151 / p 4e-35	17.5 EB05 9.1 · IC025 +2.3 3/3 methods agree	Lab value / disease marker	serious n=10	no trial arm names this drug
Alpha haemolytic streptococcal infection	10	18.9 10.2–35.3ROR 19.0 · χ² 151 / p 6e-35	17.5 EB05 9.1 · IC025 +2.3 3/3 methods agree	Not in label — unassessed	serious n=10	no trial arm names this drug
Anal fissure	56	18.5 14.2–24.0ROR 18.6 · χ² 899 / p 7e-198	18.2 EB05 14.5 · IC025 +3.5 3/3 methods agree	Not in label — unassessed	serious n=54	no trial arm names this drug
Colitis microscopic	49	18.4 13.9–24.4ROR 18.5 · χ² 780 / p 5e-172	18.1 EB05 14.2 · IC025 +3.5 3/3 methods agree	Not in label — unassessed	serious n=49	no trial arm names this drug
Chronic kidney disease-mineral and bone disorder	11	18.0 9.9–32.6ROR 18.0 · χ² 158 / p 1e-36	16.7 EB05 9.0 · IC025 +2.3 3/3 methods agree	Not in label — unassessed	serious n=11	no trial arm names this drug

Trial evidence (ClinicalTrials.gov)

ClinicalTrials.gov returned results-bearing trials mentioning Cholestyramine only as a background or rescue medication (NCT03510884, NCT02890992); no trial listing it as the tested intervention was cached, so no trial cross-check is shown.

Most frequently reported reactions

By raw co-report count, regardless of disproportionality. Common terms here are often the illness itself or generic outcomes.

Reaction	Reports	PRR 95% CI · ROR · χ²/p	EBGM EB05 · IC025	Label screen	Serious-only & strata	Trial cross-check
Diarrhoea (diarrhea)	1,695	4.6 4.4–4.8ROR 5.2 · χ² 4,921 / p <1e-300	4.6 EB05 4.4 · IC025 +2.1 3/3 methods agree	Labeled adverse reaction exact term	serious PRR 4.7	no trial arm names this drug
Off label use (used outside approved label)	1,111	2.2 2.1–2.4ROR 2.4 · χ² 788 / p 9e-174	2.2 EB05 2.1 · IC025 +1.1 3/3 methods agree	Reporting / coding artifact	serious PRR 2.6	no trial arm names this drug
Drug ineffective (drug did not work)	946	1.3 1.2–1.3ROR 1.3 · χ² 51 / p 4e-13	1.3 EB05 1.2 · IC025 +0.2	Reporting / coding artifact	serious PRR 2.2	no trial arm names this drug
Fatigue (tiredness)	905	2.0 1.9–2.2ROR 2.1 · χ² 492 / p 3e-109	2.0 EB05 1.9 · IC025 +0.9	Labeled adverse reaction exact term	serious PRR 2.3	no trial arm names this drug
Nausea	821	1.8 1.7–1.9ROR 1.9 · χ² 312 / p 5e-70	1.8 EB05 1.7 · IC025 +0.7	Labeled adverse reaction exact term	serious PRR 2.1	no trial arm names this drug
Arthralgia (joint pain)	633	2.7 2.5–2.9ROR 2.8 · χ² 670 / p 4e-148	2.7 EB05 2.5 · IC025 +1.3 3/3 methods agree	Labeled (related wording) related wording	serious PRR 3.4	no trial arm names this drug
Headache	573	1.6 1.5–1.7ROR 1.6 · χ² 131 / p 1e-30	1.6 EB05 1.5 · IC025 +0.5	Labeled adverse reaction exact term	serious PRR 1.9	no trial arm names this drug
Abdominal pain	546	4.1 3.8–4.5ROR 4.3 · χ² 1,290 / p 8e-283	4.1 EB05 3.8 · IC025 +1.9 3/3 methods agree	Labeled (related wording) related wording	serious PRR 3.9	no trial arm names this drug
Vomiting	527	2.0 1.8–2.1ROR 2.0 · χ² 253 / p 3e-57	2.0 EB05 1.8 · IC025 +0.8	Labeled adverse reaction exact term	serious PRR 2.0	no trial arm names this drug
Weight decreased (weight loss)	517	3.2 3.0–3.5ROR 3.3 · χ² 806 / p 1e-177	3.2 EB05 3.0 · IC025 +1.5 3/3 methods agree	Likely indication confounding term in indications; also in warnings	serious PRR 3.5	no trial arm names this drug
Dyspnoea (shortness of breath)	516	1.6 1.5–1.7ROR 1.6 · χ² 116 / p 2e-27	1.6 EB05 1.5 · IC025 +0.5	Labeled (related wording) related wording	serious PRR 1.6	no trial arm names this drug
Pain	486	1.4 1.3–1.5ROR 1.4 · χ² 52 / p 4e-13	1.4 EB05 1.3 · IC025 +0.3	Labeled adverse reaction exact term	serious PRR 1.5	no trial arm names this drug
Asthenia (weakness)	467	2.2 2.0–2.4ROR 2.2 · χ² 298 / p 6e-67	2.2 EB05 2.0 · IC025 +1.0 3/3 methods agree	Not in label — unassessed	serious PRR 2.1	no trial arm names this drug
Constipation	409	3.3 3.0–3.6ROR 3.4 · χ² 659 / p 1e-145	3.3 EB05 3.0 · IC025 +1.6 3/3 methods agree	Labeled adverse reaction exact term	serious PRR 3.2	no trial arm names this drug
Malaise (feeling unwell)	403	1.6 1.5–1.8ROR 1.6 · χ² 92 / p 5e-22	1.6 EB05 1.5 · IC025 +0.5	Not in label — unassessed	serious PRR 1.7	no trial arm names this drug

Unlabeled candidate signals

These flagged terms were not found in the FDA label text and do not match an artifact pattern. They are the pairs that would merit a structured assessment (temporality, dose-response, biological plausibility, consistency across databases, trial or cohort evidence). The screen has not done that; string-matching misses label wording, and a strong PRR can still be stimulated reporting, co-medication, or the disease itself.

Alveolar lung disease — n=20, PRR 203.6
Bile acid malabsorption — n=23, PRR 160.2
Thyrotoxic crisis — n=22, PRR 34.6
Faecal calprotectin increased — n=55, PRR 31.3
Gastrointestinal wall thickening — n=26, PRR 31.1
Diffuse alveolar damage — n=20, PRR 30.7
Ileal stenosis — n=22, PRR 21.8
Foreign body in throat — n=36, PRR 20.9
Vascular device infection — n=51, PRR 19.9
Cholangitis sclerosing — n=23, PRR 19.7

Want to assess one of these properly? The runbook describes the Bradford Hill / trial-evidence workflow used on the assessment page, and handoff_top1000_signals.csv lists the strongest unassessed pairs across all drugs.

Common questions

What are the most reported side effects of Cholestyramine?

In FDA FAERS, the most frequently co-reported reaction terms for Cholestyramine are diarrhoea, fatigue, nausea, arthralgia, headache, abdominal pain. These are report counts, not rates: FAERS has no denominator, reporting is voluntary and uneven, and a term can be reported because of the illness being treated rather than the drug.

Does Cholestyramine have an FDA boxed warning?

No. The FDA label retrieved for Cholestyramine has no boxed warning; see the label's Warnings and Precautions for the recognised risks.

Do FAERS signals prove that Cholestyramine causes these side effects?

No. A disproportionality signal (PRR, ROR) means a reaction is reported more often with this drug than with others in the database. That can reflect a real effect, but also the disease being treated, stimulated reporting after news or litigation, co-medications, or how reports are coded. Causality needs temporality, dose-response, biological plausibility, consistency across data sources and, ideally, trial or cohort evidence. This page screens each term against the FDA label and ClinicalTrials.gov results; it does not establish causation.

Sources & methods

FDA label via openFDA (set ID 09420793-7357-4194-8172-0b1cddb167fe, effective 20260305; matched on openfda.generic_name.exact:"CHOLESTYRAMINE")
Bayesian shrinkage measures computed offline over all 1,317,300 cached pairs: BCPNN information component (IC, with Norén closed-form IC025) and MGPS empirical-Bayes geometric mean (EBGM, EB05) with a two-component gamma prior fitted by maximum marginal likelihood (α₁=0.57, β₁=0.02, α₂=1.42, β₂=0.70, w=0.17); unstratified
FAERS pair statistics from the OpenPV build of 2026-09-14 (openFDA count= aggregation, field patient.drug.openfda.generic_name.exact, 1,145 reaction terms, min 3 co-reports); PRR/ROR with 95% CI, chi-square with Yates correction
Serious-only and stratified counts (serious:1, patient.patientsex, primarysource.qualification) from openFDA count queries; serious-only PRR uses the drug serious report total and the term global serious total (N_serious=11,882,979); strata shown only when n ≥ 20
Seriousness and sex counts from openFDA count=serious, patient.patientsex, seriousnessdeath
ClinicalTrials.gov API v2 (query CHOLESTYRAMINE, results-bearing studies sorted by enrollment)

Page generated 2026-10-08. Label and PubChem text are retrieved automatically and may lag the current label; always check the current prescribing information. OpenPV is a beta research tool of the Open Source Medicine Foundation.