Are there documented cases of poisoning from horse paste ivermectin and when were they reported?
Executive summary
Public-health reports and peer-reviewed case series document multiple human poisonings tied to ivermectin misuse, including exposures to veterinary (horse) formulations; a retrospective series from an Oregon poison center found 37 ivermectin toxicity cases Aug 14, 2021–Jan 31, 2022 with 17 linked to veterinary products and one death [1]. Federal agencies and major medical organizations warned of rising poison‑center calls and hospitalizations for ivermectin overdoses in mid‑2021 as demand surged during the COVID‑19 pandemic [2].
1. The documented cases: poison centers and a clinical case series
Health authorities and clinicians recorded concrete cases of ivermectin toxicity from both human and veterinary formulations. A retrospective analysis of Oregon Poison Center cases over a 24‑week period (14 August 2021–31 January 2022) identified 37 patients who required a healthcare visit for ivermectin toxicity; 17 of those patients had taken veterinary formulations and most were hospitalized or treated in emergency departments, and one patient died [1]. National reporting from the CDC and summaries by medical groups noted increased poison‑center calls tied to ivermectin misuse as prescriptions and interest climbed [2].
2. When the reports appeared: mid‑2021 surge and formal advisories
The spike in reports and formal warnings corresponded with mid‑2021. The AMA summarized a CDC health advisory noting a rapid rise in ivermectin prescribing through August 2021 and a concurrent increase in poison‑center calls and severe illness associated with misuse [2]. The Oregon study’s exposure window covers August 2021 through January 2022, capturing that surge in documented cases [1].
3. Veterinary “horse paste” as a specific hazard
U.S. and clinical reporting emphasized that animal formulations are highly concentrated and not intended for humans; the FDA and clinicians warned that people self‑medicating with animal ivermectin required medical attention and some were hospitalized [2] [3]. The Oregon case series explicitly separates veterinary versus human formulations and reports that many veterinary‑product exposures involved large single or repeated high doses leading to neurologic symptoms and rapid deterioration [1].
4. Clinical picture and outcomes reported in the literature
The Oregon series reports that affected patients were typically older (median age 64) and mostly male; many required hospitalization or emergency‑department care , with a range of neurologic symptoms after taking higher‑than‑recommended doses or veterinary products; one death occurred in the cohort [1]. The American Medical Association and CDC advisory linked the broader rise in ivermectin use for COVID‑19 to increases in poison‑center calls and severe illness [2].
5. What the product labels and veterinary sources say
Manufacturers’ and veterinary information explicitly state ivermectin pastes are for use in horses only, warn “Not for use in humans,” and note the high per‑syringe doses intended to treat animals weighing up to 1,250 lb — a dosing scale far above human prescriptions [4] [5]. Clinical and consumer guidance reiterates those label warnings and highlights the concentration difference between animal and human formulations [3].
6. Competing narratives and the information ecosystem
Some commentary and partisan outlets have contested the scale or interpretation of “horse paste” stories, suggesting media exaggeration or suppression of pro‑ivermectin evidence [6]. That perspective disputes mainstream public‑health messaging; however, peer‑reviewed case data and CDC/AMA advisories document increased exposures and clinical harm during mid‑2021 [1] [2]. Available sources do not mention broader claims about systematic censorship of ivermectin efficacy beyond opinion pieces [6] [1] [2].
7. Limitations, open questions, and what the sources don’t say
Published sources here quantify cases from one poison center and summarize national advisories, but do not provide a complete national count of all hospitalizations or long‑term outcomes from veterinary‑product ingestion beyond the cited period [1] [2]. Available sources do not mention detailed demographic breakdowns beyond median age/sex for the Oregon series, nor do they provide systematic toxicology data for all exposures [1]. Broader assertions about the total national toll or every individual incident are not supported by the provided materials.
8. Practical takeaway for readers
Regulatory and clinical sources agree: animal formulations of ivermectin are not approved for humans and have caused documented poisonings, especially during the mid‑2021 COVID‑related demand spike; clinicians treated dozens of severe cases in that study period and federal advisories warned the public about rising harms [1] [2] [3]. If you encounter claims minimizing those harms, compare them against peer‑reviewed case series and official advisories cited above [1] [2].