What are the approved medical indications for ivermectin in humans and their dosing schedules?
Executive summary
Ivermectin is an antiparasitic medicine approved in humans for a small set of parasitic infections (oral formulations) and for certain topical dermatologic uses; dosing is weight‑based and usually given as a single oral dose for most indications, with occasional repeat dosing depending on the infection and clinical response (Drugs.com [1]; FDA [2]; Mayo Clinic p1_s5). It is not FDA‑approved for COVID‑19 or other viral illnesses, and veterinary formulations are different and potentially dangerous if self‑administered by people (FDA [2]; MedlinePlus p1_s9).
1. Approved human indications — oral antiparasitic uses
Oral ivermectin tablets are approved to treat intestinal strongyloidiasis and onchocerciasis (river blindness) in humans, and are used in many public‑health programs and clinical settings for a range of helminth (worm) infections; international agencies and some regulators endorse broader parasitic uses such as soil‑transmitted helminths and lymphatic filariasis in combination regimens (Drugs.com [1]; Wikipedia [3]; MedlinePlus p1_s9).
2. Approved dermatologic/topical indications
Topical ivermectin formulations are approved for dermatologic uses including rosacea and head‑lice or lice infestations, with specific commercial products and concentrations licensed for skin or scalp application rather than oral consumption (Drugs.com [1]; FDA p1_s3).
3. How dosing is determined — weight‑based single doses are standard
Oral ivermectin dosing is typically weight‑based and most commonly administered as a single dose of roughly 150–200 micrograms per kilogram (mcg/kg) of body weight (examples: 150 mcg/kg cited and 200 mcg/kg in prescribing references), with tablets most often supplied as 3 mg units that are combined to reach the calculated dose (Mayo Clinic [4]; Wikipedia [3]; Medical News Today p1_s6).
4. Repeat dosing and condition‑specific schedules
Some conditions require repeat dosing: clinical guidance and specialist sources note that for scabies and strongyloidiasis clinicians may give a single dose and then repeat at about day 7–14 or at intervals of months for persistent or reinfection risk; public‑health mass‑drug administrations for onchocerciasis or soil‑transmitted helminths use programmatic schedules that differ from single‑patient therapy (Next Steps in Dermatology [5]; Mayo Clinic [4]; Wikipedia p1_s2). Precise timing and the need for retreatment should be guided by diagnostic testing and clinical response, as regulatory labeling and local protocols vary (MedlinePlus p1_s9).
5. Safety, limitations, and misuses to note
Regulators including the U.S. Food and Drug Administration emphasize that ivermectin is not authorized for COVID‑19 and that self‑medication—especially with veterinary formulations—has led to hospitalizations; approved human doses can interact with other drugs and require medical oversight, and toxic or untested high doses are dangerous (FDA [2]; MedlinePlus [6]; Drugs.com p1_s1). Available literature and drug monographs also note pediatric, geriatric, pregnancy and lactation considerations, and that dosing is adjusted for weight and clinical context (Medscape [7]; Mayo Clinic p1_s5).
6. Where guidance diverges and why agendas matter
Clinical reviews and specialty guidance sometimes recommend broader or repeat dosing ranges (e.g., 150–250 mcg/kg or repeating at 7–14 days for cutaneous infestations) that are informed by practice and small studies rather than uniform regulatory labeling, creating variation between product inserts, dermatology cheat‑sheets, and public‑health programs; this gap has been amplified in public debates around off‑label and politicized uses (Next Steps [5]; Medical News Today [8]; FDA p1_s3). Reporting and advocacy that focus on unproven antiviral claims or promote animal‑product use reflect implicit agendas and risk public harm; regulatory and evidence‑based sources should guide individual dosing decisions (FDA [2]; MedlinePlus p1_s9).