What are the approved uses and typical dosing guidelines for ivermectin in humans?
Executive summary
Ivermectin is an antiparasitic drug approved for a limited set of human indications — chiefly onchocerciasis, strongyloidiasis and other helminth infections — and is available as oral tablets and topical formulations; typical single-dose oral regimens used in many indications are about 0.15–0.2 mg/kg (for example, single doses often rounded to 3, 6, 9 or 12 mg by weight) [1] [2] [3]. Regulatory agencies do not authorize ivermectin for COVID-19, and clinical reviews and agencies say available trial data do not prove it works for that indication [3] [4].
1. What ivermectin is and the approved human uses — a short primer
Ivermectin is an antiparasitic agent discovered in the 1970s and approved for human use in the 1980s; approved human uses include treatment of infestations such as onchocerciasis (river blindness), strongyloidiasis and certain soil‑transmitted helminths, and it exists in oral and topical forms for conditions like head lice and rosacea [1] [3]. The European Medicines Agency’s CHMP has recently given a positive opinion for ivermectin combined with albendazole for several helminth infections, reflecting its continuing role in tropical neglected‑disease programs [1].
2. Typical dosing patterns used in approved parasitic indications
Standard human dosing is weight‑based and typically low relative to experimental antiviral doses: many guidance summaries cite single oral doses around 0.15 mg/kg (often operationalized as 3 mg for 15–25 kg, 6 mg for 26–44 kg, 9 mg for 45–64 kg, 12 mg for 65–84 kg, and ~0.15 mg/kg for ≥85 kg) or dosing repeated at long intervals for mass‑treatment programs [2]. For onchocerciasis, programmes commonly use a single oral dose of ~0.15 mg/kg administered every 6–12 months depending on clinical context [2].
3. Safety, pharmacology and dosing rationale
Ivermectin works by binding parasite glutamate‑gated chloride channels, causing paralysis of the parasite; it has limited central nervous‑system penetration in mammals at therapeutic doses, which underpins its safety margin in approved uses [1]. Clinical references emphasize that the approved human single doses (about 0.150–0.200 mg/kg) are far below doses that produced toxicity in animal LD50 studies, and that human regimens reflect that therapeutic window [1].
4. What regulators say about off‑label and COVID‑19 use
U.S. and other regulators state that ivermectin tablets are approved for specific parasitic infections and topical formulations for some skin conditions, but that ivermectin is not authorized or approved to prevent or treat COVID‑19; the FDA says available clinical trial data do not demonstrate efficacy against COVID‑19 [3]. Authorities warn against using veterinary formulations or taking large, unprescribed doses because of risk of harm [3].
5. The pandemic controversy and evidence context
Laboratory studies showed ivermectin inhibited SARS‑CoV‑2 in vitro at concentrations far higher than those achievable with approved human dosing, and some small clinical trials have reported mixed or limited signals — for example, a pilot trial found a 5‑day ivermectin course (12 mg once daily) shortened time to viral clearance versus placebo in one hospitalized cohort, but other evidence and regulatory reviews do not support routine use for COVID‑19 [5] [6] [4]. Reporting and reviews note that doses required to reproduce in‑vitro antiviral effects would be “much higher than the maximum approved or safely achievable” in humans [4].
6. Practical dosing guidance and cautions — what clinicians and patients should know
Authoritative dosing references provide weight‑based single‑dose charts for parasitic diseases (examples above), advise administration instructions (often taken on an empty stomach in some references), and flag repeat dosing intervals only for specific diseases and programmatic needs [2] [7]. Regulatory statements emphasize that clinicians can prescribe approved drugs off‑label in individual cases when judged appropriate, but regulators have not endorsed ivermectin for COVID‑19 and caution about overdose and veterinary product misuse [3].
7. Competing viewpoints and the politics behind demand
While many clinical and regulatory authorities reject ivermectin for COVID‑19, advocacy groups and some clinicians have promoted it as a repurposed therapy; reporting connects political and advocacy movements to surges in prescribing and recent state‑level legislative action that seeks broader access — developments that medical societies and regulators have criticized or warned about [8] [9] [4]. The divergence reflects a mix of scientific disagreement over low‑quality trial data, activism for “medical freedom,” and misinformation about veterinary versus human products [8] [9].
Limitations: This briefing relies only on the supplied sources; dosing specifics for every approved indication, pregnancy guidance, and some detailed regimen variations are covered unevenly across those documents, and additional primary regulatory labeling (package inserts) are not in the current set and therefore not cited. Available sources do not mention some granular regimen details (for example, all formulation strengths marketed in every country).