Etodolac

Limits on what this shows

• Null and reverse findings: Kasuya 2012 did not name etodolac among inhibitors [10]. A PubMed listing for etodolac with mitochondria returned only that record. No human mitochondrial function or toxicity signal for etodolac was located.

Regulatory status

No mitochondrial statement in the label sections retrieved [1].

Population evidence

None in humans. CLASS EXTRAPOLATION: Moreno-Sanchez 1999 [11] (Tier C for etodolac): the abstract text retrieved states diclofenac, piroxicam, indomethacin, naproxen, nabumetone, nimesulide and meloxicam were tested on mitochondrial respiration, ATP synthesis and membrane potential, with nimesulide, meloxicam, piroxicam and indomethacin acting as uncouplers and nabumetone inhibiting respiratory chain site 1 (via a PubMed listing summary; full text not opened). Etodolac was NOT in the cohort. Nadanaciva 2013 [12], a panel of NSAIDs in isolated mitochondria, hepatocytes and zebrafish, was seen only as OpenAlex metadata (no abstract); its keyword list did not include etodolac, so it is not used. Kasuya 2012 [10] (Tier B, in vitro): eleven NSAIDs including etodolac were tested on acyl-CoA synthetase activity in mouse liver and brain mitochondria; the abstract names diflunisal and mefenamic acid (and aspirin for octanoic acid) as inhibitors and gives no etodolac result, so an etodolac effect or null cannot be read from it (abstract reconstructed via OpenAlex; full text not opened).

Mechanism

Named for class members (protonophore-like uncoupling [11]); not shown for etodolac. Etodolac is a carboxylic acid NSAID of the pyranocarboxylic class [6] and more than 99% albumin bound [1], so free exposure is low, but whether concentrations in people reach uncoupling levels is not established.

Class cohort test

Etodolac absent from [11] and unconfirmed in [12], so the class evidence is Tier C and capped at yellow.

Counter-evidence held on record

Counter-evidence Isolated-mitochondria screens do not show clinical mitochondrial toxicity, and the one etodolac-inclusive panel did not single etodolac out. Framing caution Mechanistic plausibility only. This entry does not support any mitochondrial or antioxidant supplement and is not a deficiency claim.

Limits on what this shows

• Why no grade: Dual condition met: no Tier B or C source with an oxidative-stress endpoint was opened for etodolac or for the NSAID class in a cohort that includes it, and no circulating claim about etodolac and oxidative stress was found to rebut. This is partly tooling-limited: class-level NSAID redox literature likely exists and could not be retrieved because Crossref and PubMed listing queries were rate-limited and the WebSearch budget was exhausted. Not a finding of safety.

Channels tried

PubMed listing "etodolac oxidative stress" (opened, 7 records): a photo-oxidative degradation paper for the molecule in water, an etodolac plus alpha-tocopherol rodent Alzheimer model (listing text only, not opened), a synthetic etodolac hydrazone derivative study of sperm and testis lipid peroxidation (a different compound), an etodolac plus N-acetylcysteine obesity cardiomyopathy rat study that I opened through OpenAlex (abstract reports cardiac function and liver fibrosis and no oxidative marker) [18], and cancer cell and angiogenesis papers. Web search for etodolac with malondialdehyde, glutathione and antioxidant enzymes returned titles only, none an etodolac study I could confirm; the two RA papers it surfaced did not involve etodolac [23]. A Crossref query for class-level NSAID redox studies returned HTTP 429. Label read: no oxidative-stress statement [1].

Context, not evidence for the drug

Active rheumatoid arthritis itself is associated with higher serum malondialdehyde and lower vitamin E, beta-carotene and glutathione reductase activity [23] (no etodolac involvement), so any redox change in treated arthritis patients is confounded by indication (Hard Rule 6).

Repair attempt 2026-10-07

A second pass was made after the first review. WebSearch for etodolac with malondialdehyde and superoxide dismutase was refused (shared per-turn search budget exhausted, no results returned). Fetch-tool queries were refused with HTTP 429 and a request not to refetch: PubMed listing "etodolac antioxidant lipid peroxidation", an OpenAlex works search "etodolac oxidative stress", a Crossref bibliographic query for etodolac with oxidative stress and antioxidant, and a Europe PMC REST query combining etodolac with oxidative stress or zinc. Retries were spaced about 1.5, 4 and 5 minutes apart (one attempt per interval, none repeated against the same refused URL except the PubMed zinc listing, once) and were all refused. No new source was opened, so nothing could be graded and no source was added.

Gap type

Tooling-limited for class-level evidence; likely genuine gap for etodolac-specific evidence.

Limits on what this shows

• Null findings: The blood loss data above are near placebo and are short-exposure studies in mostly young healthy volunteers [4][5], so they do not test older arthritis patients on years of therapy. The SOS meta-analysis abstract [24] gave no etodolac estimate and is not relied on. The 0.39 odds ratio compares etodolac with naproxen (an active comparator) and says nothing about etodolac versus non-use.
• At-risk subgroups: Aspirin co-users (9-fold higher event rate with etodolac in [7]; label says concomitant aspirin is not generally recommended), warfarin users (label: GI bleeding effects are synergistic), prior ulcer history and older adults [1][7].

Regulatory status

Label sec 5.2 warns of GI inflammation, bleeding, ulceration and perforation (upper GI ulcers or bleeding in about 1% at 3 to 6 months and 2 to 4% at one year; prior ulcer history raises risk more than 10-fold). Sec 5.12 states anemia is sometimes seen with NSAIDs and may be due to fluid retention, occult or gross GI blood loss, or an incompletely described effect on erythropoiesis. Anemia, melena and GI bleeding appear in the adverse reaction lists below 1%. Iron is not mentioned [1]. Label text was read through a summarizing fetch tool, not as raw text.

Population evidence

Lanza 1989 [5]: four microbleeding studies in healthy subjects plus a 4-week arthritis patient study, 51-chromium red-cell labeling, etodolac 600 to 1,200 mg/day; per the retrieved page the greatest mean daily increase in blood loss with etodolac was 0.2 mL, versus 4 to 5 mL/day increases with aspirin and larger increases with naproxen, ibuprofen and indomethacin, and endoscopy scores after one week were similar to baseline and placebo (page read via summarizing fetch; full text not opened). Moore 2008 [4]: systematic review of 47 trials (1,162 individuals, mostly healthy young men); etodolac sat in a lower-loss group with diclofenac and meloxicam at about 0.5 to 0.9 mL/day, versus 2.0 mL/day for ibuprofen and naproxen; no etodolac-only trial count or dose was reported in the text read. Weideman 2004 [7]: historical cohort at the Dallas VA, 16,286 veterans (5,596 patient-years); clinically significant upper GI event incidence 0.24% for etodolac versus 0.78% for naproxen (odds ratio 0.39, 95% CI 0.20 to 0.76), and concurrent low-dose aspirin raised event rates about 9-fold with etodolac (abstract as retrieved from a university repository page). Zvaifler 1989 [6]: narrative review stating etodolac microbleeding was comparable to placebo. None of these measured iron, ferritin or hemoglobin.

Mechanism

Present at class level: label sec 12.1 states the mechanism may be related to prostaglandin synthetase inhibition [1], and NSAID mucosal injury can bleed. Etodolac also forms an iron(III) complex in an analytical assay [17], with no physiological meaning shown (see Overlap map).

Hard Rule 2 and 6 checks

GI bleeding and anemia are clinical outcomes, not iron deficiency. Iron deficiency needs measured iron indices. Confounding by indication is presumed: rheumatoid disease and osteoarthritis populations, aspirin co-use and chronic inflammation all affect bleeding and hemoglobin independent of the drug.

Counter-evidence held on record

Counter-evidence and confounding Low fecal blood loss and the lower event rate than naproxen weaken any claim that etodolac is an important iron-loss drug; the veterans cohort is mostly men and aspirin co-use dominated risk. Framing caution This is a toxicity pathway (blood loss), not an intake or absorption deficiency. New iron deficiency or black stools on etodolac calls for evaluating the bleeding source and the prescription, not an iron supplement by default. No iron dose is recommended here.

Limits on what this shows

• Null findings: No copper measurement for etodolac users was found, in either direction. The PubMed listing for etodolac with iron returned this paper and one related assay paper (PMID 18410679, iron(III) oxidation spectrophotometry, listing text only).

Regulatory status

No copper statement in the label sections retrieved [1].

Population evidence

None in humans or animals. Amer 2005 [17] (Tier B, in vitro analytical chemistry): etodolac formed colored complexes with copper(II) acetate (1:2 metal to drug) and iron(III) chloride (1:3), extracted and measured spectrophotometrically at 684 nm and 385 nm for pharmaceutical assay (abstract reconstructed via OpenAlex; full text not opened).

Mechanism

Metal binding by etodolac under assay conditions is demonstrated; physiological relevance (plasma concentration, competition from albumin and ceruloplasmin, effect on absorption or excretion) is not shown.

Counter-evidence held on record

Counter-evidence Metal complexation in a flask for analysis does not show depletion. Framing caution Chemical curiosity only. Not a copper deficiency or excess claim and not a reason to supplement or restrict copper. Graded separately from Iron (Hard Rule 7).

Limits on what this shows

• Null findings: No etodolac-specific microbiome study was retrieved. A PubMed listing for etodolac and microbiota was rate-limited (HTTP 429, twice) and not read; a web search for etodolac with gut microbiota, microbiome or dysbiosis returned only titles, none an etodolac study (one ketorolac rat study title was not opened).

Regulatory status

No microbiome statement in the label sections retrieved [1]. Dyspepsia (10%), abdominal pain, diarrhea, flatulence and nausea are the common GI reactions [1] and are not microbiome findings.

Population evidence

CLASS EXTRAPOLATION, Tier C: Le Bastard 2017 [16], systematic review of molecular microbiome studies of proton pump inhibitors, metformin, NSAIDs, opioids, statins and antipsychotics; NSAIDs gave inconsistent alpha diversity results, were the only class that did not significantly alter beta diversity, and, with PPIs, metformin and opioids, were associated with increased Gammaproteobacteria and Enterococcaceae (abstract reconstructed via OpenAlex). The abstract does not name the NSAIDs, so whether etodolac was in any underlying cohort is unconfirmed.

Mechanism

Plausible in principle through NSAID mucosal injury (label sec 5.2 [1]); not demonstrated for etodolac. Etodolac showed low fecal blood loss and endoscopic scores near placebo in short studies [5], which does not support a strong mucosal-injury route.

Class cohort test

Etodolac inclusion could not be confirmed, so the class result is Tier C and capped at yellow.

Counter-evidence held on record

Counter-evidence The class review found beta diversity was not significantly altered by NSAIDs, and the underlying studies are heterogeneous. Framing caution Not a dysbiosis claim for etodolac. No probiotic or other supplement is implied.

Limits on what this shows

• Null findings: None for hemolysis. A PubMed listing for etodolac with erythrocytes, methemoglobin or hemoglobin was rate-limited (HTTP 429) and not read, so the absence of other hemolysis or methemoglobin reports is tooling-limited.

Regulatory status

Label sec 5.12 (anemia causes: fluid retention, occult or gross GI blood loss, incompletely described effect on erythropoiesis) and platelet inhibition with prolonged bleeding time. Hemic and lymphatic reactions below 1%: ecchymosis, anemia, thrombocytopenia, bleeding time increased, agranulocytosis; the probable-causal list also names hemolytic anemia, aplastic anemia, leukopenia, neutropenia and pancytopenia [1].

Population evidence

Cunha 2000 [8] (Tier B, case report): a patient developed severe Coombs-positive hemolytic anemia after taking etodolac on two separate occasions; the serum reacted only weakly with normal red cells but strongly with red cells exposed to an active urinary etodolac glucuronide, and the authors concluded sensitivity was to the glucuronide rather than the parent drug (abstract reconstructed via OpenAlex; full text not opened). No controlled hemoglobin, hematocrit or arterial oxygenation study in etodolac users was retrieved.

Mechanism

Immune, drug-dependent antibody to a metabolite (glucuronide) on red cells [8]. The GI blood loss and fluid retention routes named in the label are covered in the Iron and Sodium entries and are not counted again here.

Hard Rule 2 check

Hemolytic anemia from an idiosyncratic immune reaction is a drug adverse event. It is not an oxygen-delivery nutrient deficiency and not iron deficiency, and it implies no supplement.

Counter-evidence held on record

Counter-evidence and confounding One case report and a below 1% label frequency; chronic inflammatory disease itself lowers hemoglobin, and older arthritis patients carry other bleeding risks. Framing caution A monitoring prompt (blood count), not a deficiency claim. New unexplained anemia on etodolac belongs with the prescriber. No supplement is implied.

Limits on what this shows

• Null findings: None found that measured ATP or energy status with etodolac. No human fatigue, lactate or energy-status data were located.

Regulatory status

No ATP or energy-metabolism statement in the label sections retrieved [1].

Population evidence

None in humans. CLASS EXTRAPOLATION: Moreno-Sanchez 1999 [11]: ATP synthesis was one of three endpoints for seven NSAIDs that did not include etodolac (magnitudes and concentrations not read). A PubMed listing for etodolac with ATP returned four records that concern ATP release as a signaling molecule or cancer cell studies (listing text only, not opened), not cellular ATP production by etodolac.

Mechanism

Uncoupling lowers the proton gradient that drives ATP synthase in isolated preparations [11]; not shown for etodolac, and intact-cell ATP was not measured for it.

Class cohort test

Etodolac was not in the cohort of [11]; Tier C, capped at yellow.

Counter-evidence held on record

Counter-evidence Cells compensate for modest uncoupling, and the evidence is not independent of the Mitochondrial burden entry (see Overlap map). Framing caution Do not translate this into a fatigue or low-energy claim for etodolac users. No supplement is implied.