What are the known risks and side effects of taking ivermectin at doses proposed for COVID-19 prevention?
Executive summary
Health authorities and clinical reviews report that ivermectin is not authorized or proven for COVID-19 and that doses used by people seeking prevention have produced serious adverse events including neurologic symptoms, gastrointestinal upset, hypotension, seizures, liver injury and even death; a poison‑center series found neurologic effects (confusion, seizures) and GI symptoms among 40 self‑treated patients with doses ranging 12–1,360 mg/day [1] [2]. Large clinical trials and regulators conclude ivermectin does not reduce COVID‑19 hospitalizations or progression at tested regimens, and major agencies warn against its use outside trials [3] [1] [4].
1. Why people tried high or off‑label ivermectin for COVID‑19 — and what regulators say
During the pandemic some laboratory and small clinical studies, plus prominent public figures, promoted ivermectin as a possible antiviral, which drove demand and even legislation easing access [5] [6] [7]. Major health agencies countered: the FDA has not authorized ivermectin for prevention or treatment of COVID‑19 and states available trial data do not show efficacy; the WHO likewise recommends against routine use outside clinical trials [1] [3] [8].
2. Known adverse effects reported when people self‑medicated
Reports collected by poison centers and hospitals describe acute adverse events after self‑treatment. A Tennessee Poison Center series of 40 cases (median age 53) found 28% with confusion, 20% with other central nervous system symptoms and four seizures; 33% had nausea/vomiting, several had hypotension and cases of lactic acidosis were reported, with daily doses from 12 to 1,360 mg cited [2]. Broader clinical and public health warnings list nausea, vomiting, diarrhea, hypotension, decreased level of consciousness, confusion, blurred vision, hallucinations, loss of coordination, seizures, coma and death as possible overdose or severe‑adverse outcomes [8] [1].
3. How proposed COVID‑19 doses compare with approved dosing — toxicity implications
In vitro antiviral activity against SARS‑CoV‑2 was observed only at concentrations that would require oral doses far above approved human dosing; one analysis estimated 50% inhibition would require roughly 7.0 mg/kg — many times the FDA‑approved maximum — which raises poisoning risk when people take high or repeated doses [8]. Clinical trials testing higher regimens (for example 400 µg/kg for 3 days) have not demonstrated clear benefit for preventing hospitalization, reinforcing that pushing doses higher to chase efficacy risks toxicity without proven benefit [4] [8].
4. Hospitalizations, organ injury and rare but serious outcomes
Multiple hospital and media reports warned that misuse — especially veterinary formulations or extreme doses — led to hospitalizations and, in some reporting, organ failure or death; public health messaging emphasized that animal ivermectin products are different and dangerous for people [3] [9] [10]. Academic and clinical outlets also describe liver injury, severe GI upset, seizures and coma in cases linked to misuse [11] [8].
5. Conflicting viewpoints in the literature and why they persist
Some reviews and smaller studies have argued for potential prophylactic or therapeutic effects and cite clinical series or docking/in vitro work supporting ivermectin’s antiviral potential [5]. However, regulators and larger randomized trials concluded there is no reliable evidence of clinical benefit for COVID‑19 at safe doses and that safety data are inadequate in many positive studies, a point raised by manufacturers and agencies [3] [1] [12]. The disagreement largely centers on study quality, dosing extrapolations from lab data, and selective reporting — not on the absence of harm when ivermectin is overdosed [5] [8] [12].
6. Practical takeaways and limitations of available reporting
Available reporting uniformly cautions against using ivermectin for COVID‑19 outside clinical trials because (a) efficacy is unproven in robust trials and (b) real‑world misuse has produced neurologic, gastrointestinal and cardiopulmonary adverse events and occasional severe outcomes [1] [2] [8]. Limitations: some pro‑ivermectin papers and local programs claim benefit [5] [12], and the dataset of adverse events is evolving; sources do not provide a definitive frequency estimate for all harms across populations and do not fully resolve whether narrowly controlled dosing regimens might be safe or effective — clinical trials cited found no clear benefit at tested doses [4] [1].
If you want, I can summarize the specific symptoms and typical timeframes reported after overdose, or list the official guidance text from FDA, WHO and CDC verbatim as cited in these sources.