Have there been documented adverse events from humans taking veterinary ivermectin?
This fact-check may be outdated. Consider refreshing it to get the most current information.
Executive summary
Published case series and reports document human adverse events after people took veterinary ivermectin, especially when doses exceeded human recommendations or non‑oral (parenteral) veterinary formulations were used; one review identified 37 toxicity cases with one death and many hospitalizations, and a case report links intravenous veterinary ivermectin plus high oral doses to neurotoxicity (median age 64; many hospitalized) [1] [2] [3].
1. Documented cases: hospitalizations, neurologic injury, and at least one death
Several peer‑reviewed summaries and reports describe real patients harmed after taking veterinary formulations or excessive doses of ivermectin for COVID‑19 prevention/treatment. A PubMed analysis identified 37 cases of ivermectin toxicity (most older men), with the majority hospitalized and one death noted; 17 of those patients had taken veterinary products [1]. An NEJM report described 21 people who used ivermectin for COVID‑19 prevention or treatment, six of whom were hospitalized for toxic effects; some of those hospitalized had obtained veterinary formulations or ingested high doses [3].
2. Severe neurologic toxicity tied to route and excessive dosing
Case literature makes clear that neurologic signs — ataxia, confusion, seizures, coma — are the dominant severe adverse events and occur particularly when dosing exceeds recommended human regimens or when non‑oral veterinary administration is used. A published case report concluded an intravenous bolus of a veterinary ivermectin product combined with oral doses >0.4 mg/kg/day produced neurotoxicity in a COVID‑19 patient, and the authors emphasized that parenteral veterinary formulations are not designed or tested for humans [2].
3. Veterinary products: different formulations, higher concentrations, and added risks
Sources emphasize that veterinary ivermectin comes in formulations and concentrations intended for animals (including injectable and paste forms) and may contain excipients not evaluated for humans; those features increase overdose risk when people self‑medicate. Extension and veterinary faculty statements note that veterinary formulations are not designed for humans and that use in people can produce nausea, vomiting, neurologic adverse events and even death [4] [5] [6].
4. Patterns in reported misuse: older males, higher or repeated doses, and social drivers
Analyses of cases show a pattern: predominantly older males ingesting larger‑than‑recommended amounts, sometimes repeatedly, often for COVID‑19 prevention. The mixed‑methods BMJ Open study of community use in the context of Chagas disease and the pandemic documented social and economic drivers for veterinary ivermectin use and reported participant concerns and some self‑reported adverse outcomes, though that study noted follow‑up and causality were often unclear [7] [8].
5. Limits of the public record and causality assessments
Available reports document adverse events temporally associated with veterinary ivermectin ingestion, but several sources caution that determining direct causality is complex: doses vary, co‑medications and comorbidities are common, and many veterinary formulations and dosing practices are heterogeneous. The BMJ Open authors explicitly state that some reported adverse outcomes lacked clear linkage to vet‑IVM because of inadequate follow‑up [7]. Systematic reviews cited in these reports warn serious events cannot be ruled out at high doses, but definitive incidence rates in the general population are not established in the provided sources [8].
6. Regulatory warnings and clinical guidance
Regulatory and clinical commentaries repeatedly warned against using veterinary ivermectin in humans. FDA and clinical guidance referenced in extension and news sources list possible side effects including dermatologic, gastrointestinal, hepatic and serious neurologic events, and explicitly advise against animal formulations for human COVID‑19 treatment [4] [5]. The case literature reinforces that parenteral veterinary administration poses special danger because human ivermectin is only approved as oral tablets in standard practice [2].
7. Competing interpretations and practical takeaways
Some communications framed ivermectin as a hopeful repurposed drug early in the pandemic, but randomized trials did not show benefit for COVID‑19; in that context, off‑label use of veterinary products exposed people to avoidable harm [2] [3]. Public‑health messaging therefore balances two facts from the cited sources: ivermectin has an established human therapeutic window for certain parasitic diseases, but veterinary formulations and supratherapeutic dosing have produced documented toxicity in humans [5] [1].
Limitations: these sources document cases and warnings but do not provide a comprehensive population incidence of vet‑ivermectin harms or exhaustive causal proof for every reported symptom; available sources do not mention long‑term outcomes beyond acute hospital reports except where case authors followed individual patients [7] [1].