Cholestyramine

Limits on what this shows

• Why no grade: Dual condition met: no Tier B or C source was opened showing a cholestyramine effect on mitochondria, and no circulating claim of cholestyramine mitochondrial damage was found among the Tier D pages opened [20][21]. A disclosed gap, not a finding of safety. Mixed result: partly tooling-limited because the consumer-claim search was cut short by the search budget.

What was searched

WebSearch: "cholestyramine mitochondrial function liver mitochondria bile acids hepatic mitochondrial dysfunction cholestyramine treatment"; "cholestyramine oxidative phosphorylation OR mitochondrial respiration OR mitochondrial permeability transition bile acid sequestrant hepatocytes"; "cholestyramine mice liver mitochondria OR reactive oxygen species OR Nrf2 OR oxidative stress high-fat diet NASH bile acid sequestrant". PubMed listing: cholestyramine AND (ATP OR oxidative phosphorylation OR oxidative stress). Results were bile acid and bile duct ligation mitochondrial toxicity papers (titles only, not opened, none with cholestyramine as an intervention in the title), and a healthy-volunteer trial [16]. That trial raised ALT and the necrosis marker GLDH in some subjects on 8 g three times daily for 11 days; it was read through a summarizer and arm sizes were not verified. GLDH is a mitochondrial matrix enzyme, but its rise marks hepatocyte injury and no mitochondrial function endpoint was measured, so it is not accepted as mitochondrial evidence. LiverTox [3] reports mild transient ALT elevations in about 11% and no clinically apparent injury.

Channel outcomes

WebSearch worked until the shared 200-call budget ran out. PubMed article and PMC pages returned bot checks. PubMed listing pages worked intermittently with 429 limits. No Crossref or OpenAlex title search for this category succeeded.

Repair pass 2026-10-04

Channels retried: PubMed listing (cholestyramine AND mitochondria; cholestyramine AND ATP OR energy metabolism OR oxidative phosphorylation), 429 on both, tool asked not to retry; OpenAlex search (cholestyramine mitochondria), 429; Crossref bibliographic and title searches (cholestyramine mitochondria, hepatic mitochondrial function respiration, ATP), one returned only unrelated mitochondrial respiration papers with no cholestyramine record and the others returned 429; Europe PMC REST, 400 then 429; PLOS and MDPI site search, blocked by robots rules; WebSearch refused (budget of 200 used). Opened in this pass and checked for mitochondrial or ATP endpoints: the duck aflatoxin-cholestasis study [29] (not measured), and the LDL oxidation studies [26][27][28] (not measured). Hepatic disease confounding applies to any future finding: bile acid-driven mitochondrial injury in cholestasis is a disease mechanism, and a cholestyramine effect there would be hard to separate from lowering of toxic bile acids.

Limits on what this shows

• Null findings: Duck model, Toxins 2024 [29]: Cherry Valley ducks, 60 per group (6 replicates of 10), aflatoxin B1 with cholestyramine 6000 mg/kg diet for 4 weeks. Cholestyramine lowered total bile acids and bilirubin but did not change serum T-SOD, GSH-Px, GSH or MDA versus the AFB1 group in the text read, while taurine and emodin groups showed MDA trends; there was no cholestyramine-only arm, and mitochondrial and ATP endpoints were not measured (full text via a summarizing fetch; p-values for these markers were not returned). Kersting [28] found no fall in vitamin E.
• Hepatic disease confounding: The human cohorts [26][27][28] were hypercholesterolemic or familial hypercholesterolemia patients without a stated hepatic disease, which limits (but does not exclude) hepatic confounding. Cholestasis and liver injury independently raise oxidative stress (bile duct ligation models were seen as titles only and not opened), and cholestyramine is often given to people with cholestatic liver disease, so any redox change seen in that population cannot be assigned to the drug alone. The duck model [29] is a toxin-induced cholestasis model, so its null result is also disease- and toxin-confounded.

Regulatory status

No oxidative stress or antioxidant statement in the label sections read [1].

Population evidence

Hoffman, Brook and Aviram, Atherosclerosis 1992 [26]: 18 hypercholesterolemic patients studied on pravastatin, bezafibrate and cholestyramine (per-drug group sizes not given in the abstract text read). For cholestyramine, ex vivo LDL malondialdehyde fell 41%, peroxides 25% and conjugated dienes 63%, LDL cholesterol fell 27% and triglycerides rose 28% (two separate summarizing fetches of the abstract agreed on these cholestyramine figures; the drug-by-drug attribution of the other agents differed between the two fetches). The authors attribute the effect to the hypolipidemic effect and some change in LDL composition. Hussein, Frydman, Frim and Aviram, Pathophysiology 2001 [27]: 16 children with heterozygous familial hypercholesterolemia on cholestyramine 8 g/day for 2 months then 12 to 16 g/day for 2 months, compared with 10 healthy children (not a placebo arm). LDL cholesterol fell 14% (P=0.07), LDL malondialdehyde (TBARS) fell 30% (P=0.02), in vitro LDL oxidation fell 23%, and red-cell glutathione peroxidase and glutathione transferase activities fell 29% and 24% (abstract reconstructed from OpenAlex; full text not opened). The reconstructed abstract states both that vitamin E "increased 65%" and that LDL became less oxidation-prone "despite lower vitamin E content"; that internal inconsistency means the vitamin E direction in [27] is not used here. Kersting, Selenka and Walch, J Clin Pharmacol 2000 [28]: 25 hyperlipidemic patients on statins, 12 randomized to add cholestyramine 12 g/day for 12 weeks and 13 controls; vitamin E stayed in the normal range (11.90 to 11.69 mg/L) and the vitamin E/LDL-C ratio rose, authors concluding antioxidant status appeared improved (abstract reconstructed from OpenAlex; full text 403).

Mechanism

Not established. The authors of [26] attribute the lower LDL oxidizability to the lipid-lowering effect and altered LDL composition. Lower LDL burden and a different LDL particle are not by themselves a change in systemic redox status. The lower red-cell glutathione enzyme activities in [27] are ambiguous: they could reflect lower oxidative load or lower antioxidant defense, and the abstract does not say which.

Cohort test

Passed for [26], [27], [28] and [29]: cholestyramine was a named study drug in each. This is not class extrapolation. Hoffman [26] and Kersting [28] are not cholestyramine-only or cholestyramine-versus-placebo designs, and the cohorts of [26] and [27] share an investigator (Aviram), so they are counted as related rather than fully independent.

Hard Rule 2

LDL oxidizability is a property of the lipoprotein, driven in part by the drug's intended LDL lowering. It is not a systemic oxidative stress or antioxidant-capacity measurement, and a drop in it is not filed as a deficiency or as evidence of benefit. No circulating redox status marker (plasma total antioxidant capacity, glutathione, isoprostanes) was measured in the human studies opened.

Why yellow

Tier A human data with this drug in the cohort exist, but the marker is lipoprotein oxidizability, the direction is protective or ambiguous, and no study shows depleted antioxidant capacity. Yellow is the reverse-direction grade; it is not orange because there is no bounded deficit to show.

Counter-evidence held on record

Counter-evidence and confounding All three human studies are small, short, open-label or uncontrolled for the redox endpoint, and use surrogate markers. LDL lowering itself reduces substrate for oxidation. The duck null result and the lower red-cell glutathione enzyme activities do not support a clear protective effect, so the net picture is unclear rather than beneficial. Shares sources with the Vitamin E entry (see Overlap map): [27] and [28] report vitamin E values that run against the label-based depletion framing in that entry, which this repair pass did not edit. Framing caution Not an antioxidant or anti-aging claim and not an oxidative stress warning. Do not suggest antioxidant supplementation from this entry. No dose is given here.

Limits on what this shows

• Null findings: West and Lloyd [5]: iron "did not change significantly" in 18 children; [6]: no malabsorption of minerals in 19 children. No human iron absorption study was located.

Regulatory status

Not in the label warnings. "Anemia" appears in the adverse reaction list as an outcome [1]; it is not filed here as iron deficiency (Hard Rule 2).

Population evidence

Thomas, Salsburey and Greenberger, Am J Dig Dis 1972 [10]: rats on chow with 2% or 5% cholestyramine for 6 months. At 5%: serum iron 158 vs 205 ug% (P<0.001), liver nonheme iron 143 vs 206 ug/g, spleen 1030 vs 1482 ug/g, with significant falls in hemoglobin and hematocrit (abstract only; n not given). Watkins 1985 [11]: rats on 2% for one month had a lower net positive iron balance, attributed to resin binding (abstract only). A 1985 review of drug-nutrient mechanisms lists cholestyramine as binding iron and decreasing its absorption (PubMed listing record 3881283; abstract not opened in full) [25].

Mechanism

Present at Tier B: luminal binding or reduced absorption in animals [10][11].

Counter-evidence held on record

Counter-evidence and confounding Rat doses of 2% to 5% of diet over months are not comparable with human exposure. Human data are pediatric and abstract-level. Framing caution Monitoring prompt for people with other iron-loss risks. Not an iron deficiency claim for cholestyramine. No dose is given here.

Limits on what this shows

• Null findings: No study isolating a cholestyramine effect on copper was located.

Regulatory status

Copper is not mentioned in the label sections read [1].

Population evidence

Cywes and Millar 1990 [24]: 11 children with biliary atresia (4 on cholestyramine); cholestatic children had "raised serum copper levels" with zinc deficiency to a lesser extent than fat-soluble vitamin deficiency (PubMed record, summarizing fetch). The copper result is not reported by cholestyramine status. Watkins 1985 [11] measured calcium, magnesium, iron and zinc in rats, not copper, in the abstract read.

Mechanism

No cholestyramine copper-binding mechanism was found in any opened source.

Counter-evidence held on record

Counter-evidence and confounding Confounding by indication is the entire signal. Graded yellow only as a context flag, because copper was measured in a cohort including cholestyramine users; it is not evidence that the drug alters copper. Framing caution Do not suggest copper supplementation or copper restriction from this entry.

Limits on what this shows

• Null findings: No study found a loss of diversity or pathogen overgrowth attributable to cholestyramine.

Regulatory status

No microbiome statement in the label sections read [1].

Population evidence

Li et al., Gut Microbes 2021 [13]: 33 patients with icteric primary biliary cholangitis given cholestyramine, sampled at baseline, 4 and 16 weeks, shotgun metagenomics. Responders (by bilirubin fall) showed enrichment of two Lachnospiraceae species and higher short-chain fatty acids; Klebsiella pneumoniae appeared only in inferior responders (abstract reconstructed from OpenAlex; full text 403). Newman et al., Microbiome Res Rep 2024 [14]: C57BL/6J mice on Western diet plus 2% cholestyramine for 10 to 11 weeks, 5 per group per experiment; alpha diversity increased and 14 taxa moved toward control-diet levels (full text via summarizing fetch). Mouse and human directions are reported as restorative or response-linked.

Class extrapolation

CLASS EXTRAPOLATION (colesevelam): Kumar et al., Front Microbiol 2023 [15], 134 to 135 patients with bile acid diarrhea on colesevelam only. Cholestyramine was NOT in that cohort, so it is Tier C and capped at yellow. It reports lower alpha diversity in bile acid diarrhea itself, which is a disease effect.

Mechanism

Present: bile acid pool depletion alters bile acid-microbe signalling; cholestyramine reduces luminal bile acids [1]. Direction of risk not shown.

Counter-evidence held on record

Counter-evidence and confounding The human study has no untreated arm described in the abstract, is in a cholestatic disease where microbiome is already altered, and links changes to response rather than harm. Not orange for that reason. Framing caution Not a microbiome damage claim. Monitoring is not applicable; this is a research flag.

Limits on what this shows

• Null findings: None located for hemoglobin in humans.

Regulatory status

Label adverse reactions list "anemia" and prolonged prothrombin time [1]. The label gives no hemoglobin data.

Population evidence

Thomas 1972 [10]: significant falls in hemoglobin and hematocrit in rats on 5% cholestyramine (abstract only). West and Lloyd [5]: no significant change in iron or B12 in children; hemoglobin itself was not reported in the text read. The folate fall in [5][6] is the only human circulating-nutrient finding that could plausibly affect red cells; no anemia was reported in the text read.

Mechanism

Indirect only, through iron, folate and B12 availability. No direct effect on oxygen binding, arterial oxygenation or hemolysis was found.

Counter-evidence held on record

Counter-evidence and confounding Anemia in cholestasis or bowel disease has its own causes. Not counted as separate evidence from the Iron, B12 and Folate entries. Framing caution Anemia is a clinical outcome, not a nutrient deficiency. Not a claim that cholestyramine reduces oxygen carrying capacity.

Limits on what this shows

• Why no grade: Dual condition met: no Tier B or C source for ATP and no circulating claim found in the Tier D pages opened. Ungraded separately from Mitochondrial burden per Hard Rule 7, though the search outcomes are shared. Partly tooling-limited.

What was searched

The mitochondrial queries above also targeted respiration and oxidative phosphorylation. PubMed listing: cholestyramine AND (ATP OR oxidative phosphorylation OR oxidative stress) returned ten records; the closest were a mouse cholestasis sepsis paper (PMID 28380377, bile acids and NLRP3 inflammasome, where ATP is a signalling input), a pentachlorophenol poisoning chapter (cholestyramine as an elimination aid, uncoupling attributed to the toxin) and a buckwheat protein paper. None measures ATP production in cholestyramine-treated subjects or cells (summarizer reads of the listing only).

Channel outcomes

As for Mitochondrial burden. No dedicated ATP depletion query could be run after the search budget ended.

Repair pass 2026-10-04

The same Crossref, OpenAlex, PubMed listing and Europe PMC queries described under Mitochondrial burden were retried with ATP, energy metabolism and oxidative phosphorylation terms and were blocked or rate-limited (429, 400, robots rules); none returned a cholestyramine record. The duck study [29] and the LDL oxidation studies [26][27][28] were opened and do not measure ATP, respiration or energy output. Still no circulating consumer claim of cholestyramine "low energy" or ATP effect was found in the Tier D pages opened [20][21][22]. Tooling-limited as well as a literature gap; re-check with working PubMed access (cholestyramine with respiration, membrane potential, ATP, energy expenditure).