What dose ranges of ivermectin are safe for different medical conditions?

1. Approved, routine dosing: the 150–200 mcg/kg standard

For the conditions for which ivermectin is FDA‑approved and widely used (onchocerciasis, strongyloidiasis and several helminth infections), standard oral dosing is weight‑based and usually around 150–200 micrograms (mcg) per kilogram taken as a single dose; treatment may be repeated every 3–12 months depending on the disease and clinical response ^{[1] [5] [6]}. Sources such as Mayo Clinic and Medical News Today describe this single‑dose, weight‑based approach as the baseline for routine human use ^{[1] [5]}.

2. Situation‑specific higher and repeated dosing: scabies, filariasis, mass campaigns

Some diseases require different schedules: mass drug administration for bancroftian filariasis has used 0.4 mg/kg (400 mcg/kg) orally once yearly in large field studies, sometimes combined with other drugs ^[2]. Patients with crusted scabies or immunosuppression often require multiple doses spaced days to weeks apart; guidance and trials note repeat dosing is common in refractory or severe cases ^{[2] [6]}.

3. Experimental and high‑dose research: tolerance vs. approval

Clinical pharmacology studies have deliberately escalated ivermectin dosing to explore safety. A dose‑finding protocol and older human trials report tolerance of single doses as high as 800 mcg/kg and, in experimental contexts, exposures scaled up to 2000 mcg/kg have been discussed as “well tolerated” in some studies—these are investigational dose ranges, not standard of care ^{[3] [4]}. The NIH COVID‑19 treatment guidance emphasizes that achieving in‑vitro antiviral concentrations would require doses far above approved regimens and that ivermectin is not FDA‑approved for COVID‑19 ^[7].

4. Safety profile and limits: what the studies show

Controlled human studies of escalating doses found ivermectin generally well tolerated up to several times the usual dose, with no clear central nervous system toxicity at tested higher levels, but those trials were small and carefully monitored ^[4]. Animal toxicity data and pharmacokinetic modeling provide context that toxic thresholds are much higher than routine doses, but translating animal LD50s to human safety is complex and not a basis to recommend very high doses ^{[3] [8]}.

5. Common misuses and misinformation: antiviral claims and overdose risk

Multiple authoritative reviews state ivermectin is not approved for viral infections, including COVID‑19; cell‑culture antiviral activity does not translate to safe, effective human dosing because required plasma levels exceed approved doses by large margins—up to an estimated 100‑fold according to NIH summaries ^[7]. Reports and guidance warn that taking far‑higher doses has caused severe adverse events in some cases; sources note serious toxicity can include neurologic and systemic effects although detailed clinical event lists are drawn from broader reporting ^{[8] [7]}.

6. Practical takeaway for patients and clinicians

For approved parasitic indications, follow weight‑based prescribing: commonly 150–200 mcg/kg as a single oral dose, with condition‑specific repeats as advised by guidelines or specialist sources ^{[1] [6]}. Higher dosing regimens exist in research and mass‑treatment programs (e.g., 400 mcg/kg yearly for filariasis), but these are programmatic or investigational and require medical oversight ^{[2] [3]}. Ivermectin is not approved for COVID‑19 and available sources caution against using unapproved, high doses for viral diseases ^[7].

Limitations and conflicts in the record: trials testing high doses are small and context‑specific; programmatic mass‑treatment doses differ from individual therapeutic regimens ^{[3] [2]}. Some third‑party dosage summaries repeat standard ranges but are not authoritative ^[9]. Where sources do not specify pediatric cutoffs, note that safety in children under 15 kg is generally not established in reviewed materials ^[5].