What are the known side effects and risks of taking ivermectin for respiratory infections?

1. What ivermectin is and why this matters for respiratory uses

Ivermectin is an antiparasitic drug approved for conditions such as onchocerciasis and strongyloidiasis and used topically for some skin conditions; it was developed for livestock and later adapted for human parasitic disease ^[2][5]. Interest in using ivermectin for viral or other respiratory infections led to off‑label use and study, but safety data come mostly from its approved indications and short clinical trials rather than large randomized trials for respiratory diseases, so safety profiles applied to respiratory‑infection patients are extrapolated from existing human and toxicology data ^[4][1].

2. Common, usually transient side effects documented in humans

Across clinical studies and drug reference databases, the most frequently reported effects at standard doses are headache, dizziness, nausea, diarrhea, fatigue, and rash or pruritus; some trials report mild elevations in liver enzymes and peripheral edema in a small percent of patients ^[1][6][7]. These events are typically reversible and were reported at similar rates in ivermectin and placebo groups in some studies, indicating that mild adverse events are common but usually not dose‑limiting at approved regimens ^[1][8].

3. Respiratory and severe neurological risks that demand caution

Respiratory-specific adverse events described in drug safety summaries include worsening bronchial asthma, laryngeal edema, dyspnea, and, at high doses or in toxicity, respiratory depression and respiratory distress syndrome ^[3][2][9]. Serious neurological events—encephalopathy, ataxia, seizures and even coma—have been reported rarely in humans, particularly in contexts of high parasite loads (Loa loa) or suspected central nervous system vulnerability; such events can coincide with or contribute to respiratory compromise ^[3][4][2].

4. Who is at higher risk: interactions and vulnerable groups

People taking drugs that depress the central nervous system (opioids, benzodiazepines, barbiturates) or medications that inhibit metabolic pathways for ivermectin (certain antifungals, antivirals) may experience amplified CNS and respiratory depression or higher ivermectin levels, raising the risk of serious side effects ^[10]. Patients with pre‑existing respiratory disease, liver or kidney impairment, seizure disorders, or those exposed to veterinary formulations or overdoses also face elevated risks ^[11][12][9].

5. Overdose, animal products, and dose‑related harms

Toxicity is often a matter of dose and formulation: animal ivermectin preparations and large overdoses have produced profound CNS depression, coma, seizures, and respiratory collapse in both animals and humans who mistakenly ingest veterinary products ^[12][9][13]. Pharmacokinetic analyses show that antiviral effects seen in vitro require concentrations far above human therapeutic plasma levels, which underlies reports of people taking excessive doses and encountering dose‑related toxicity ^[1][8].

6. Practical takeaways and remaining uncertainties from the reporting

The documented safety record at approved doses shows mostly mild, transient side effects but also a clear set of rare, serious risks—notably neurological and respiratory—whose likelihood increases with overdose, drug interactions, certain infections (e.g., high Loa loa burden), or preexisting respiratory disease ^[3][4][10]. The evidence base specifically for treating respiratory infections remains limited and extrapolative, and efficacy questions affect risk–benefit calculus; available reports do not resolve whether off‑label use for respiratory disease yields net benefit sufficient to justify those risks ^[4][1].