What are the approved human indications and dose schedules for ivermectin in infectious diseases?

1. What ivermectin is approved to treat in people

Regulatory and clinical sources list ivermectin as approved for several neglected tropical and dermatologic conditions: onchocerciasis (river blindness), intestinal strongyloidiasis (threadworm), certain soil‑transmitted helminthiases, and as an option for scabies and parasitic arthropod infestations such as head lice; topical ivermectin formulations are also approved for rosacea in some jurisdictions ^{[2] [3] [1]}.

2. Standard dose schedules and common regimens

The canonical approved regimen for many adult parasitic infections is a single oral dose of roughly 150–200 mcg/kg, taken on an empty stomach, with most product labels and dosing guides using 200 mcg/kg as the typical target for strongyloidiasis and similar infections ^{[4] [5] [6]}. For onchocerciasis, pivotal trials and product labeling supported single‑dose regimens in the 150 mcg/kg range, while dermatology references commonly recommend 150–250 mcg/kg with a repeat dose at day 7 or 14 for scabies and strongyloidiasis when clinically indicated ^{[7] [8] [5]}.

3. Repeat, maintenance, and special‑population dosing

Repeat dosing is not universally required but is advised in situations such as immunosuppression, persistent infection, or community mass‑drug administrations; clinicians may repeat doses every 3–12 months or use monthly suppressive therapy for persistent strongyloidiasis in high‑risk patients, and follow‑up stool examinations are standard to document eradication ^{[9] [5] [6]}. Safety and efficacy data are limited in children under 15 kg and elderly patients may need dose caution due to comorbid hepatic, renal or cardiac disease ^{[6] [9]}.

4. Upper limits, off‑label high‑dose studies and pharmacology caveats

Regulatory labeling cites a maximum recommended human dose of 200 mcg/kg as the standard on a mg/m2 basis, though clinical research has explored much higher doses (in some trials up to 2,000 mcg/kg) for vector control or other experimental uses; these higher doses have been tolerated in specific study settings but are outside routine approved practice and raise pharmacokinetic and safety questions ^{[4] [10] [7]}. Food increases ivermectin bioavailability—high‑fat meals can raise exposure roughly 2.5‑fold—information relevant when considering off‑label dosing or toxicity risk ^[7].

5. Safety, interactions and neurotoxicity warnings

Ivermectin is generally well tolerated at approved doses but carries documented risks and drug interactions: clinicians are advised to monitor for neurotoxicity (ranging from somnolence to, rarely, severe central effects), interactions with P‑glycoprotein modulators and warfarin, and to assess for Loa loa exposure before treating patients from endemic regions because of serious adverse event risk ^{[11] [6]}.

6. The COVID‑19 controversy and guideline stance

Although in vitro data suggested ivermectin can inhibit SARS‑CoV‑2 replication, clinical guideline panels and regulators do not endorse ivermectin for COVID‑19 because randomized trials do not provide convincing evidence of benefit and pharmacokinetic modeling indicates antiviral concentrations seen in cell culture would require doses far above approved human regimens ^{[2] [12]}. Alternative viewpoints exist—small trials and observational reports have suggested possible signals—but major treatment guidelines emphasize lack of approval for viral infections and warn about self‑medication and dosing beyond labeled limits ^{[2] [12]}.