Oseltamivir

Limits on what this shows

• Null findings: The rat study had no oseltamivir-alone arm, so it cannot show absence of harm [12]. A rat study with intraperitoneal oseltamivir 100 mg/kg did not measure mitochondrial parameters [13].
• At-risk subgroups: Not definable from animal data. The fish result concerns early development, which is a reason the authors raise for caution about overuse, not a human finding.

Direction

Mixed. Adverse in a developing-fish exposure model; protective in an adult rat cardiotoxicity model. Neither is a nutrient deficiency.

Regulatory status

No mitochondrial statement in the Tamiflu label sections read [1].

Population evidence

None in humans. Wang 2024 [11] (Tier B, oseltamivir phosphate specific; abstract read via a PubMed record through a summarizer): zebrafish larvae at doses the authors call environmentally and therapeutically relevant showed higher expression of oxidative-phosphorylation genes, altered respiratory chain complex activity, lower mitochondrial membrane potential and hyperactive behavior; co-treatment with acetyl-L-carnitine or nicotinamide riboside reduced the behavioral effects. Sample sizes and doses were not in the abstract. Qin 2021 [12] (Tier B, summarized from the Frontiers article page): 36 male rats in control, doxorubicin and doxorubicin plus oseltamivir (20 mg/kg oral) groups; oseltamivir lowered Drp1, PINK1 and Parkin, improved mitochondrial ultrastructure on electron microscopy and preserved ejection fraction. There was no oseltamivir-only group and membrane potential and ATP were not measured.

Mechanism

Proposed in both papers (mitochondrial dysfunction in the fish; neuraminidase-1 to Drp1 mitophagy in the rat) and not demonstrated in humans. The rat paper itself notes the NEU1 mechanism is unclear [12].

Counter-evidence held on record

Counter-evidence The two animal sources point in opposite directions. Exposure in fish is waterborne and chronic during development, which differs from a short human oral course with a half-life of 6 to 10 hours for the carboxylate [1]. Human mitochondrial function (respirometry, lactate, mtDNA) was not measured in any oseltamivir study found. Framing caution Not a claim of human mitochondrial toxicity. The carnitine and nicotinamide riboside rescue in the fish does not imply that people taking oseltamivir need those supplements.

Limits on what this shows

• Null findings: Most oseltamivir-alone comparisons in the rat study were non-significant [13]. A mouse combination paper [15] reports a triple-combination TBARS and glutathione reductase effect, but oseltamivir-alone values were not available in the abstract.

Direction

Reverse or neutral. No depletion signal.

Regulatory status

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

Population evidence

None in humans on oseltamivir. Guzmán 2016 [13] (rats, intraperitoneal 100 mg/kg for 5 days, full text read through a summarizer): stomach GSH was higher with oseltamivir in uninfected rats (33.94 versus 31.80), cortex H2O2 was lower in Salmonella-infected rats (0.121 versus 0.142, p < 0.04), most other GSH, H2O2 and calcium comparisons were not significant; MDA and SOD were not measured. Qin 2021 [12]: in doxorubicin-treated rats, oseltamivir attenuated falls in serum SOD, GSH and total antioxidant capacity and the rise in H2O2. Mileva 2020 [14] (mice; abstract read via OpenAlex): oseltamivir 2.5 mg/kg with S-adenosylmethionine improved lung oxidative stress markers; oseltamivir-alone marker values were not in the abstract and were not retrieved. In humans, Nikam 2010 [16] found higher MDA and lower GSH, SOD and GPx in 30 untreated H1N1 patients than in 30 controls, measured before treatment, so it describes the disease and not the drug.

Mechanism

No oseltamivir-specific redox mechanism is established. Reduced viral load and inflammation, or Neu1 inhibition, are suggested in the papers and are not tested in humans.

Counter-evidence held on record

Counter-evidence and confounding The rat dose (100 mg/kg intraperitoneal) is far above human oral exposure and is not a clinical route. All redox changes in infection models are confounded by viral load. Human influenza oxidative stress [16] is an indication effect. Framing caution Not an antioxidant-benefit claim and not an antioxidant-depletion claim. No supplement is suggested.

Limits on what this shows

• Why no grade: Dual condition met: no Tier B or C evidence supports even a yellow grade, and no circulating consumer claim about oseltamivir and copper was found to rebut. This is a disclosed gap, not a finding of safety. Kept independent of Iron (Hard Rule 7).

What was searched

PubMed listing "oseltamivir AND (copper OR iron OR zinc OR ferritin)" (10 records returned, none measuring copper in treated people or animals). The listing included a 2026 Neuro-oncology paper on NEU1, lysosomal Cu2+ and mitochondrial lysis in glioblastoma (PMID 42015369), which uses oseltamivir only as a known NEU1 inhibitor; only its listing title was read, it is not opened and is not copper status evidence [21]. A Giardia Raman study showing iron redox changes in parasite cells (PMID 38787210) is irrelevant to human copper. Web search "oseltamivir nutrient depletion vitamin mineral Tamiflu depletes" returned only news and product pages. The label sections read contain no copper statement [1]. Drugs.com lists no nutrient interactions [20].

Channel outcomes

PubMed listing: worked for 6 queries with 429 responses between them. PubMed and PMC article pages: reCAPTCHA bot check (PMC11768443, PMC8233933), so no article was read there. Crossref, OpenAlex keyword search, Europe PMC: not reachable (OpenAlex keyword search returned a fetch error; Crossref returned 429 with a do-not-retry notice). WebSearch budget was exhausted before the last two planned queries. Repair pass: the dedicated copper-only PubMed query "oseltamivir copper" was run and returned 6 records (PMIDs 42015369, 35839640, 38955298, 23517385, 34795865, 26686050): the glioblastoma NEU1/lysosomal copper paper [21] (oseltamivir used as a NEU1 inhibitor with elesclomol in xenografts; outcomes were tumor growth and survival, not copper levels; listing-level read only, not opened) and five chemistry papers in which copper is a catalyst or click-chemistry reagent. None measured copper, ceruloplasmin or copper status in people or animals given oseltamivir. A broader query for oseltamivir carboxylate with copper, mitochondria or iron terms did not parse as intended (it returned unrelated copper literature with no oseltamivir content) and a cleaner "oseltamivir carboxylate cytotoxicity" query (18 records, 10 read) returned only neuraminidase-inhibitor chemistry papers with no copper, mitochondrial, redox, red-cell or iron measurement. The DailyMed label was re-read in full for copper and ceruloplasmin: absent [1]. PubChem toxicity data: no copper or hematologic statement. WebSearch for oseltamivir with serum copper or ceruloplasmin could not run (shared search budget exhausted). Genuine gap; the remaining tooling limit is that PubMed article pages, Europe PMC and Crossref were not usable.

Limits on what this shows

• Why no grade: Dual condition met: no Tier B or C source for iron status and no circulating claim to rebut. Hyperferritinemia in severe influenza is a disease effect (Hard Rule 6), not a drug-iron finding. Not a finding of safety.

What was searched

The same PubMed mineral listing as Copper. Hits that mention iron-related labs were all inflammation or hemolysis context: two case reports with markedly raised ferritin in oseltamivir-treated patients (an adult with influenza B hemophagocytic lymphohistiocytosis, PMID 41583267, and a pediatric H5N1 case, PMID 42515601), identified from listing text only and not opened, and a hemolytic anemia case with ferritin 6,016 ng/mL and iron saturation 60% attributed by the authors to post-viral immune dysregulation [17]. Ferritin in these cases is an acute-phase marker. Label sections read give no iron statement; antacid and calcium carbonate co-administration needs no adjustment [1]. PubMed "oseltamivir AND (vitamin OR carnitine OR folate)" (32 records, 10 read) flagged no measured micronutrient levels. Repair pass: PubMed "oseltamivir AND (ferritin OR iron deficiency OR serum iron OR hepcidin)" (11 hits, 10 listed and read at abstract or listing level): ferritin was recorded as an acute-phase or admission marker in influenza, H5N1, HLH and COVID-19 reports, one retracted trial listing (PMID 33790308) with no ferritin result, and Legionnaires' disease reports (PMIDs 20457347, 20457348) where patients were not an oseltamivir-treated group; in no record was an iron or ferritin change attributed to oseltamivir, no hepcidin or iron-absorption study was returned, and the label's only iron mention is iron oxide capsule-shell colorant [1].

Channel outcomes

Same as Copper. The label describes no acid-dependent or transporter-dependent absorption step [1], and it reports GI bleeding and hemorrhagic colitis as postmarketing events [1], which would be a blood-loss pathway rather than an absorption one, though no iron measure accompanies them. No cohort relating oseltamivir to iron deficiency was found. Genuine gap with a tooling-limited component (WebSearch budget exhausted; PubMed article pages not usable).

Limits on what this shows

• Null findings: The in vitro study reported little overall effect [7]. Al Khatib 2021 [10] profiled stool microbiota in 38 influenza patients and 11 controls but the record read does not state whether oseltamivir was considered, so it supplies no drug data.
• At-risk subgroups: Not defined. Hospitalized patients receiving antibiotics, probiotics and enteral feeding are heavily confounded [9].

Direction

Compositional change of uncertain direction; small in the cleanest model.

Regulatory status

No microbiome statement. The label lists hemorrhagic colitis and GI bleeding as postmarketing events, notes under 20% fecal excretion, and warns that the sorbitol-containing suspension may cause diarrhea in hereditary fructose intolerance [1].

Population evidence

Zhao 2022 [7] (in vitro fermentation of human fecal communities; Chinese-language abstract page read through a summarizer, n not stated): Bacteroidaceae and some other taxa fell, a few taxa rose, short-chain fatty acid production and metabolic pathways were not clearly affected, and the authors concluded the effect on the community was small; drug degradation varied from 8.6% to 88.4% between donors. Cui 2023 [8] (ICR mice with influenza; oseltamivir 27.5 mg/kg/day for 3 days before infection; 10 mice per group): oseltamivir samples clustered near controls on PCoA and showed enrichment of Lactobacillus-related taxa, Bacillales and Staphylococcus; influenza infection itself changed the microbiota. There was no uninfected oseltamivir-only arm. Qin 2015 [9] (Scientific Reports; 26 H7N9 patients all receiving oseltamivir, 17 also on antibiotics, versus 31 healthy controls): diversity was lower, with E. coli and Enterococcus faecium enriched and Faecalibacterium prausnitzii and Roseburia reduced. All patients received oseltamivir, so no drug-free comparison exists.

Mechanism

Oseltamivir inhibits viral neuraminidase and may inhibit some bacterial sialidases, but no source opened tested sialidase inhibition in gut commensals; the sialidase search result was not opened. Treat the mechanism as unestablished.

Counter-evidence held on record

Counter-evidence and confounding Influenza changes the gut microbiota by itself [8][9][10], which is the main confounder. The human series used no oseltamivir-free patient arm, and mouse feces were taken on day 4 after infection only. Effects of a 5 day oral course on human stool communities have not been tested in a controlled study that was found. Framing caution This is not a dysbiosis claim. Do not extend antibiotic microbiome findings to oseltamivir, which is an antiviral without antibacterial activity in the sources read.

Limits on what this shows

• Null findings: The rat doxorubicin paper did not measure ATP [12]. No human ATP, phosphocreatine, lactate or exercise-capacity data in oseltamivir users were found.

Direction

Reduced ATP content in a fish larval model. Not a nutrient deficiency.

Regulatory status

No energy-metabolism statement in the label sections read [1].

Population evidence

None in humans. Wang 2024 [11] reports reduced ATP content with lower mitochondrial membrane potential in zebrafish larvae (abstract level only; magnitude, doses and n not retrieved). Guzmán 2016 [13] measured Ca2+/Mg2+ ATPase activity in rat brain regions and stomach after intraperitoneal oseltamivir 100 mg/kg for 5 days (cortex 356.89 versus 272.04, higher, p < 0.02; stomach lower, p value not stated). Hydrolytic enzyme activity does not measure ATP synthesis, so that result is context only and is not used to support this grade.

Mechanism

Inferred in the fish from impaired respiratory chain complex activity and membrane potential [11]. Not demonstrated for humans.

Counter-evidence held on record

Counter-evidence One abstract-level animal source supports this entry, and it is the same source as the adverse arm of the Mitochondrial burden entry (see Overlap map). It should not be counted as a second line of evidence. "Low energy" with influenza is a disease symptom. Framing caution Do not present as a human energy-production deficit. Kept separate from Mitochondrial burden and Oxygen delivery/utilization per Hard Rule 7.

Limits on what this shows

• Why no grade: Dual condition met: no drug-attributable Tier B or C evidence and no circulating claim about oseltamivir and oxygen-carrying capacity. Anemia would be an outcome, not a nutrient (Hard Rule 2). Kept independent of ATP production (Hard Rule 7). The influenza-attributed hemolysis case is disease context and is not filed as a drug effect. Oseltamivir-associated thrombocytopenia [26] is a platelet event and an adverse-event outcome (Hard Rule 2), so it is not graded under this category.

What was searched

Web search "oseltamivir anemia OR hemolysis OR hemoglobin OR methemoglobinemia OR thrombocytopenia case report adverse hematologic" and PubMed listing "oseltamivir AND (anemia OR hemolysis OR hemoglobin OR methemoglobinemia)" (10 records, sorted by date): none attributed a red-cell effect to oseltamivir. Closest hits were an influenza A hemolytic anemia in a 22-year-old man (Hb 11.7 g/dL, LDH 1,991 U/L, haptoglobin under 30 mg/dL, schistocytes) who received oseltamivir and dexamethasone, attributed by the authors to post-viral immune dysregulation [17], and a toddler with influenza B anemia and thrombocytopenia (listing only, not opened). The only consistent hematologic signal is platelets: a 2024 Haematologica letter reported higher platelet counts after oseltamivir in hospitalized patients (mean fold change 1.14) with no hemoglobin or hemolysis data [18], and a Malaysian regulator alert (January 2021) cites thrombocytopenia from four Swiss reports and 61 WHO database cases [19]. Platelets are not oxygen delivery. Repair pass: PubMed "oseltamivir AND (hemoglobin OR anemia OR hemolysis OR thrombocytopenia)" (10 records read) found one drug-attributed hematologic event, thrombocytopenia in a 68-year-old woman about 2 weeks after starting oseltamivir plus probenecid in a pharmacokinetic study (Naranjo 7, probable), with 93 FAERS reports of thrombocytopenia or decreased platelets and a significant disproportionality signal for oseltamivir but not probenecid [26] (read as an OpenAlex record summary; the PubMed page returned a bot check). All other records were immune thrombocytopenia treatment papers (oseltamivir used as a possible therapy, "well tolerated") or unrelated. PubMed "oseltamivir AND (methemoglobinemia OR hemolytic anemia OR aplastic anemia OR G6PD)" (10 records): none attributed hemolysis, anemia or methemoglobin to oseltamivir; influenza-associated hemolytic uremic syndrome and toddler anemia cases had the anemia present before or independent of oseltamivir. Two 2010 Turkish Journal of Haematology letters address G6PD deficiency: a 5-year-old boy with known G6PD deficiency received oseltamivir 45 mg twice daily for 5 days with "no hemolytic anemia" (hemoglobin and LDH values not reported) [24], and a follow-up exchange in which the author notes that G6PD-deficient subjects were excluded from the pharmacokinetic studies and that "further studies are needed" [25]. Together these are a null case report and an open question, not a hemolysis signal. A triple-antiviral critical care trial listing states no antiviral toxicity occurred in either group (PMID 21968371; abstract level, not separately cited). The label re-read found no anemia, hemoglobin, hemolysis, thrombocytopenia or platelet term [1].

Channel outcomes

The Tamiflu label sections read list no anemia or hematologic adverse reaction [1]. PubMed listing worked; PubMed article pages and PMC returned bot checks. A Cochrane and a Lancet IPD meta-analysis of oseltamivir exist, but the Lancet abstract could not be reconstructed (OpenAlex abstract null) and no hemoglobin outcome was reported in the Cochrane abstract read [3]. Repair pass channels: PubMed listings worked for 4 further queries with 429 responses between them (waits of 2 to 3 minutes helped); OpenAlex single-record lookups worked (PMIDs 19637952, 27263461, 27265800); the Turkish journal PDFs and the PubChem toxicity record opened; OpenAlex keyword search failed again; WebSearch was out of budget. Genuine gap with a tooling-limited component. The null G6PD case report is counter-evidence, not a Tier B basis for a yellow grade.