Tinidazole

Direction

Drug toxicity in a genetic subgroup (outcome), plus an unproven mitochondrial route by class extrapolation. Not a nutrient deficiency (Hard Rule 2).

Regulatory status

Current label [1]: contraindicated "in patients with Cockayne syndrome"; section 4 states severe irreversible hepatotoxicity or acute liver failure with fatal outcomes "have been reported after initiation of" a nitroimidazole (the summarizing tool reported the label cites metronidazole cases; the wording after "of" was not seen), and postmarketing section 6.2 lists severe irreversible hepatotoxicity with very rapid onset. LiverTox via PubChem [4]: likelihood score "E*" (suspected but unproven rare cause of clinically apparent liver injury); no rate of enzyme elevations; usually short courses. Label: no pharmacokinetic data in hepatic impairment; use cautiously [1].

Class evidence, CLASS EXTRAPOLATION (Tier C for tinidazole)

Hernandez Herrera 2025 [19] (ercc6-deficient zebrafish): metronidazole caused complete lethality in mutants while wild types survived; mutants had higher oxygen consumption; the SOD mimetic MnTBAP restored it; ATP not mentioned; reactive species proposed, not measured. Xiao 2019 [18] (primary human neurons and cell lines, six antibiotics): metronidazole induced apoptosis but, unlike tigecycline, azithromycin and clindamycin, did not raise ROS; the abstract attributes respiratory-complex dysfunction to tigecycline, azithromycin and clindamycin and not to metronidazole; tinidazole was not tested. Both abstracts read as OpenAlex records.

Cohort test

Tinidazole was not in either research cohort. The label Cockayne statement is regulatory text, not a mitochondrial measurement.

Search record

PubMed "tinidazole mitochondria" returned 1 record (a Giardia review; no ATP or mitochondrial data) [30].

Counter-evidence held on record

Counter-evidence and confounding No mitochondrial measurement with tinidazole exists in anything read, and the Xiao result for metronidazole ran away from a mitochondrial or oxidative mechanism. The label's Cockayne contraindication is a regulatory precaution derived largely from a sibling drug. Framing caution Cockayne syndrome is a rare genetic condition and this is a drug-safety contraindication, not evidence that tinidazole damages mitochondria in other people, and it implies no supplement.

Direction

Mechanistic and bacterial only; no host redox finding.

Regulatory status

No oxidative-stress statement. The older label copy reports tinidazole was positive for in vivo genotoxicity in the mouse micronucleus assay and mutagenic in some bacterial strains (older copy [2]), a DNA-damage finding and not a redox marker.

Tinidazole-specific evidence (Tier B)

Mol Med Rep 2020 [28]: H. pylori cultures treated in vitro with tinidazole for 6, 12 and 24 hours showed higher ROS and lower SOD activity (PubMed listing summary; bacterial cells, not host; numbers not retrieved). Green tea study [22]: 36 mice given metronidazole or tinidazole with or without green tea; mitotic index and micronucleus counts changed in bone marrow and spleen; the abstract reports no oxidative markers.

Human context (cohort unconfirmed)

Saudi J Gastroenterol 2012 [20]: 20 anemic H. pylori patients randomized to iron plus anti-H. pylori therapy or iron alone; protein carbonyls fell and total antioxidant status rose only in the combined group. Tinidazole is a MeSH index term, the abstract names no antibacterial; infection-linked improvement, not a drug-caused rise.

Class evidence (Tier C)

Hassan 2020 [16] (metronidazole in rats): higher oxidative markers in cerebellar and testicular tissue after 60 days at 400 mg/kg/day. Xiao 2019 [18]: metronidazole did not raise ROS in human neurons.

Cohort test

Tinidazole was in [28] (bacteria), [22] (mice, genotoxicity endpoints only) and, by index term only, [20]. It was not in [16] or [18].

Counter-evidence held on record

Counter-evidence and confounding The bacterial ROS finding is the drug's intended action on target microbes. The one human redox study measured improvement after treating infection. The class results conflict (rat markers up, human neurons no ROS). Framing caution A mechanistic note only. It does not show that tinidazole lowers antioxidant capacity in a person, and no antioxidant supplement is implied.

Limits on what this shows

• Counter-evidence: The iron-only arm did not improve, which implies the infection treatment, not the iron, drove the change; it says nothing about tinidazole causing iron loss. The metronidazole dossier's iron data (102 children with giardiasis on metronidazole alone) [33] were not carried: tinidazole was not in that cohort.

Direction

No depletion signal. Indication-linked improvement after infection treatment (context flag).

Regulatory status

No iron statement in either label; "ferric oxide yellow" appears only as a tablet colorant [1][2].

Human evidence (Tier A design, cohort unconfirmed)

Saudi J Gastroenterol 2012 [20]: 20 anemic, H. pylori-infected patients randomized to ferrous sulfate plus anti-H. pylori therapy (group I) or ferrous sulfate alone (group II); 15 healthy controls. After 1 month iron, hemoglobin and ferritin rose significantly in group I and did not change significantly in group II. Group sizes and values were not in the abstract record. The abstract names no antibacterial; the MeSH indexing lists tinidazole, clarithromycin and lansoprazole.

Search record

PubMed "tinidazole ferrous" returned 1 record (this one); "tinidazole iron" and "tinidazole hemoglobin OR ferritin" returned 429 and were not read; "tinidazole hemolytic" returned 1 hydroxyapatite materials study [30].

Counter-evidence held on record

Counter-evidence and confounding Combined iron plus antibacterial therapy against iron alone, with the antibacterial unnamed in the abstract; sample of 20; Hard Rule 6 applies (infection treatment improves iron handling). Framing caution Not an iron-loss claim. Unusual fatigue or pallor during a course is a clinical question, not a supplement signal.

Direction

Neutral in the one human measurement; chemistry runs nutrient-to-drug, not drug-to-nutrient.

Regulatory status

No copper statement in either label [1][2].

Human evidence (Tier A, mixed exposure, abstract level)

Olivares 2003 [12]: serum copper measured before and 3 months after treatment in 25 children with giardiasis given tinidazole and metronidazole; the abstract reports significant differences for copper only in the Enterobius group (pyrantel), and in the Giardia group only magnesium. Inferred from abstract wording; no values (Karger abstract page, full text paywalled).

Chemistry (Tier B)

Ramirez-Palma 2023 [21]: tetrahedral [Cu(II)(tnz)2X2] (X = Cl, Br) complexes and their DNA recognition; synthetic coordination chemistry with no physiological or copper-status claim. A second paper on copper complexes with norfloxacin and tinidazole (Acta Crystallogr B 2022) was seen as a title only [31] and not opened.

Mechanism

Absent as a drug effect on copper status.

Counter-evidence held on record

Counter-evidence and confounding The copper null is inferred from abstract wording of a mixed-drug, infection-linked cohort. Coordination chemistry in a flask does not show copper binding in the gut. Framing caution Not a copper deficiency claim and not a copper-excess claim. No copper product is implied.

Direction

Disturbance of the gut microbial community (a risk entry, expected pharmacology). Not a nutrient deficiency and no supplementation implication (Hard Rules 2 and 5).

Regulatory status

Neither label copy read contains a gut-flora, microbiome or C. difficile statement [1][2]. The current label says tinidazole "does not appear to have activity against most strains of vaginal lactobacilli" (microbiology section) [1], and the older copy records vaginal fungal infection in 4.7% of 235 women in a bacterial vaginosis trial [2].

Tinidazole-specific evidence (Tier B, in vitro)

Jokipii 1987 [8]: broth dilution against 38 Clostridioides difficile strains and 11 Peptostreptococcus anaerobius strains. Mean MICs were metronidazole 0.13 and 0.11 ug/mL and tinidazole 0.16 and 0.17 ug/mL; "on a molar basis" the two were equally active, and tinidazole's relative activity rose as susceptibility fell. This supports activity against gut anaerobes by the same class mechanism. It is not a stool study and no human gut measurement exists in it.

Tinidazole in human or animal studies at other sites (not gut)

Vaginal: in women with bacterial vaginosis, oral tinidazole plus two Lactobacillus probiotics raised indigenous L. iners or L. crispatus [24] (PubMed listing summary; numbers not retrieved). Penile: a phase 1/2 trial in 125 Ugandan men randomized to four antimicrobial arms, one of them oral tinidazole, found the antimicrobials reduced foreskin HIV-target CD4+ T cells and inflammation, tracking penile bacterial change [25] (listing summary; tinidazole-arm results not retrieved). Mouse: a liposomal silver-tinidazole formulation cleared tumor-associated bacteria in colorectal cancer models and was designed to avoid gut dysbiosis [23] (listing summary; the formulation is not oral tinidazole and gut data were not retrieved).

Class evidence, CLASS EXTRAPOLATION (Tier C for tinidazole)

Lewis 2005 [14] (metronidazole alone, healthy volunteers, randomized): in 16 SRB-positive volunteers fecal sulphate-reducing bacteria fell (95% CI 2.19 to 3.36, p < 0.0001), fecal anaerobes fell, and short-chain fatty acids fell (95% CI -103.7 to -19.6, p = 0.007). Gotfred-Rasmussen 2021 [15] (metronidazole n = 48 versus placebo n = 48 in children, 275 stool samples): Hungatella, Sutterella and Streptococcus rose at 2 weeks specific to metronidazole, and 7 of 8 changed genera were back to pretreatment levels by 8 weeks. Both are abstracts read as OpenAlex records. Tinidazole is not mentioned in either record.

Cohort test

Tinidazole was NOT in the cohort of Lewis [14] or Gotfred-Rasmussen [15]; the metronidazole dossier's red gut-microbiome grade [33] rests on those studies and was not carried over. Frontiers in Medicine 2021 [32] (H. pylori triple therapy and gut microbiota, 40 patients) was opened and its regimen (omeprazole, clarithromycin, amoxicillin) contains no tinidazole, so it fails the test too. Multi-drug H. pylori regimens that contain tinidazole exist in the registry literature (Hp-EuReg listing line [30]) but no microbiome endpoint was seen for them.

Search record

PubMed "tinidazole gut flora" returned 4 records and "tinidazole AND (microbiome OR microbiota OR dysbiosis OR 16S)" returned 15 (10 summarized): none was a human gut-microbiome study with tinidazole as the studied exposure [30]. Crossref title listing for "tinidazole" (208 records, 200 viewed) showed no gut-flora study [31]. Europe PMC, Semantic Scholar and OpenAlex search endpoints returned 429 or client errors.

Red hunt

Red needs two independent Tier A tinidazole sources measuring gut flora directly; none exists. Orange needs one; none exists. Yellow is the ceiling: Tier B in vitro activity plus a labeled class extrapolation. A tinidazole-alone stool study (16S or culture) with a comparator would move this entry.

Counter-evidence held on record

Counter-evidence and confounding Equal molar activity against anaerobes in a MIC test does not give a stool effect size, dose-response or recovery time for tinidazole, whose half-life (about 13 hours) and 2 g single-dose or 3 to 5 day schedules differ from metronidazole's. The label's adverse-reaction pools cover single 2 g doses and multi-day courses [2], so exposure per course varies. Competing explanations in any future study include the infection treated (giardiasis, bacterial vaginosis) and co-prescribed drugs. Framing caution This is a disturbance risk by class extrapolation, not a measured tinidazole finding and not a deficiency. It implies no probiotic, fiber or vitamin supplement. Do not read the metronidazole red grade as a tinidazole result.

Direction

Context flag only; no hemolysis or anemia signal for tinidazole in anything read. Not an intended pharmacologic effect on oxygen delivery.

Regulatory status

Current label: use with caution "in patients with evidence of or history of blood dyscrasia"; "may produce transient leukopenia and neutropenia", with no persistent abnormality in clinical studies; reversible thrombocytopenia is listed among rare reports [1][2]. No anemia, hemolysis, methemoglobin or hemoglobin statement.

Human evidence (cohort unconfirmed)

Saudi J Gastroenterol 2012 [20]: hemoglobin rose after iron plus anti-H. pylori therapy, not with iron alone (see Iron for design and limits); this is the same single source, not independent confirmation.

Search record

PubMed "tinidazole hemolytic" returned one hydroxyapatite-loaded materials study reporting no hemolytic activity in human red cells (not a drug-exposure study, not used) [30]. "tinidazole anemia" returned 429.

Counter-evidence held on record

Counter-evidence and confounding A single small trial with unnamed antibacterials; infection treatment and iron supplementation both explain a hemoglobin rise. Framing caution Not an oxygen-delivery deficiency. New pallor, dark urine or breathlessness during a course needs a clinical review and a blood count, not a supplement.

Limits on what this shows

• Why no grade: Dual condition met on the channels reachable: no Tier B or C source measures ATP, respiration or membrane potential for tinidazole or supports a yellow, and no circulating claim was found to rebut as white. Kept independent of Mitochondrial burden and Oxygen delivery/utilization (Hard Rule 7). This is a disclosed gap, not a finding of safety; re-check with PubMed and Europe PMC access.

What was searched

PubMed "tinidazole mitochondria": 1 record (a Giardia review; no ATP data) [30]. PubMed "tinidazole oxidative stress": 6 records (bacterial ROS, degradation chemistry, an H. pylori anemia trial, a fungal gene study); none reports ATP [30]. Crossref title listing "tinidazole" (208 records, 200 viewed): no energy-metabolism study [31]. Label and PubChem reference sections: no ATP or mitochondrial pharmacology beyond the Cockayne contraindication [1][4][5]. Metronidazole zebrafish work [19] reports oxygen consumption but not ATP and is class evidence for a different drug.

Channel outcomes

The open-web search budget was exhausted before consumer-claim searches for energy or ATP could run, so absence of a circulating claim is tooling-limited. PubMed phrasings "tinidazole ATP" and "tinidazole respiration" were not run (listing rate limits, 429), so the evidence-side gap is partly tooling-limited and partly genuine.