Are there any reported cases of ivermectin toxicity in humans at high dosages?
Executive summary
Reported human ivermectin toxicity at high doses has been documented in poison-control and public-health reporting, with symptoms ranging from nausea and dizziness to seizures, coma and death; U.S. poison-control centers and federal agencies have recorded spikes in exposure calls during periods of misuse [1] and the FDA warns that overdoses can cause seizures, coma and death [2]. Medical references and drug guides note that veterinary formulations and high-dose regimens pose particular overdose risks and that adverse events have been reported when people take non‑prescription or animal products [3] [4] [5].
1. What the surveillance data show: poison centers and public-health warnings
During the COVID-era surge in interest in ivermectin, U.S. poison-control centers reported large increases in calls about ivermectin exposures—one report described a 163–245% rise in exposure reports in 2021—and public reporting tied that rise to people taking veterinary products or higher-than‑recommended doses [1] [6]. Federal agencies such as the FDA and CDC have repeatedly warned that misuse and overdose reports increased and that overdoses can cause serious neurologic and systemic effects including ataxia, seizures, coma and death [2] [7].
2. Clinical manifestations recorded or warned about by regulators and clinicians
Authoritative sources list a wide spectrum of overdose effects: gastrointestinal upset (nausea, vomiting, diarrhea), hypotension, allergic reactions, dizziness, problems with balance, seizures, coma and death; these are explicitly cited by the FDA and echoed in mainstream coverage and medical guidance [2] [8]. Drugs.com and other drug‑information resources similarly note that misuse—especially of veterinary products—may result in overdoses and adverse effects, and clinical reactions may also include inflammatory responses when used in parasitic infections with heavy microfilarial loads [3] [9].
3. How “high dose” is defined—and where toxicity concerns come from
Approved human dosing is weight‑based and typically about 200 micrograms per kilogram as a single dose for approved parasitic indications; most safety guidance and case reports reference harms when people take doses far above this, or use veterinary formulations intended for much larger animals [10] [3]. Laboratory and pharmacokinetic analyses have also warned that antiviral in‑vitro effects would require oral doses many times higher than approved human doses—levels “high enough to be considered ivermectin poisoning” in some summaries—flagging a gap between experimental antiviral targets and safe human exposure [11].
4. Documented clinical cases vs. aggregate exposure reports
Available reporting includes aggregate poison‑control exposure increases and regulatory warnings; individual case reports of severe outcomes (seizure, coma, death) tied to ivermectin overdose are referenced in regulatory language and news coverage, and some media and hospital reports have described individual overdose admissions, but systematic, peer‑reviewed case-series quantifying lethal overdoses from ivermectin in humans are not prominent in the provided sources [1] [2] [12]. Some commentators dispute the frequency of fatal overdoses—citing pharmacovigilance reviews that argue serious events are uncommon when ivermectin is used in approved ways—but that view does not negate the recorded poisoning reports tied to misuse [13].
5. Special clinical situations: veterinary products and underlying infections
Multiple sources emphasize that the greatest hazard has been people ingesting veterinary ivermectin formulations meant for horses or livestock; these products are more concentrated and may contain non‑pharmaceutical excipients, increasing overdose risk when used by humans [3] [4]. Separately, in endemic settings, very high parasite loads (for example, Loa loa) can produce serious neurologic adverse events after standard ivermectin dosing—an important nuance showing that toxicity may arise both from overdose and from drug–parasite interactions [11].
6. Competing perspectives and limitations in the record
Some proponents and clinicians argue ivermectin has a wide safety margin and contend deaths from overdose are rare or unproven in systematic reviews; one commentator quoted an expert saying no single death from ivermectin overdose had been identified in his review [13]. That position contrasts with FDA, CDC and poison‑control data documenting overdose exposures and listing severe potential outcomes [2] [1]. Available sources do not mention a comprehensive, peer‑reviewed national-level mortality tally specifically attributing deaths solely to ivermectin overdose between 2021–2025—so precise incidence and mortality rates remain unclear in the materials provided (not found in current reporting).
7. Practical takeaways for readers
Regulatory agencies and mainstream medical references consistently advise: use prescription ivermectin only for approved indications at recommended weight‑based doses, avoid veterinary products, and seek urgent care for signs of neurologic or systemic toxicity; these are the consistent safety messages across the FDA and drug‑information guides cited [2] [3] [4]. If you are following experimental or off‑label regimens reported online, be aware that anecdotal “protocols” and high‑dose cancer claims exist but carry documented overdose risks and are not supported by established efficacy data in cancer or COVID‑19 [14] [5] [15].
If you want, I can compile specific reported exposure numbers and cited headlines from poison‑control and news reports, or search academic databases for peer‑reviewed case reports of severe human ivermectin toxicity.