What are the licensed milligram strengths and labeled dosing regimens for prescription human ivermectin tablets in different countries?
Executive summary
Prescription human ivermectin tablets are marketed in low-milligram strengths—most commonly 3 mg per tablet—with labeled dosing regimens that are weight‑based and indication‑specific, usually expressed in micrograms per kilogram (mcg/kg) with single‑dose administration for many parasitic infections and occasional repeat or mass‑campaign schedules such as annual 0.4 mg/kg for filariasis in some programs [1] [2] [3].
1. Tablet strengths on the market: small‑dose human tablets, not livestock syringes
The standard, licensed human oral formulation in the U.S. is Stromectol, supplied as 3 mg tablets, a strength repeatedly noted in product information and clinical references (each tablet contains 3 mg) [1] [4] [5], while some manufacturers and global suppliers list 6 mg and 12 mg human tablet presentations for certain markets and bulk supply, particularly from Indian manufacturers and private label exporters [6]. Public clinical resources and prescribing guides emphasize human tablet dosing by body weight and explicitly warn against veterinary formulations [2] [7].
2. Typical labeled regimens: 150–200 mcg/kg as the clinical default
For common human parasitic infections the labeled and routinely recommended single‑dose regimens fall in the 150–200 mcg/kg range: regulatory labeling and clinic guides cite 150 mcg/kg to 200 mcg/kg as standard single‑dose options depending on the indication [8] [1] [9]. Authoritative product labeling for Stromectol documents that a single 200 mcg/kg dose is efficacious for strongyloidiasis in clinical trials and is used in practice [4], while dermatology and prescribing cheat‑sheets commonly reference 150–250 mcg/kg with repeats for scabies or strongyloidiasis if needed [10].
3. Repeat dosing and indication‑specific schedules: scabies, strongyloidiasis, onchocerciasis
Some conditions call for repeat dosing: scabies and strongyloidiasis are often treated with an initial single weight‑based dose (typically around 150–250 mcg/kg) with a repeat dose at day 7 or day 14 when indicated [10]. Onchocerciasis (river blindness) campaigns use approximately 150 mcg/kg dosing in single administration strategies as the standard for community distribution [8] [7], but ivermectin does not kill adult Onchocerca worms and repeated community treatments are part of control strategies [9].
4. Public‑health and mass‑treatment regimens vary: higher annual doses in some programs
Mass‑drug‑administration programs sometimes adopt different schedules: a large field study cited mass treatment for bancroftian filariasis in Papua New Guinea using 0.4 mg/kg (400 mcg/kg) given once yearly alongside other agents as part of multi‑year control efforts [3]. Such regimens are specific to public‑health programs and differ from routine clinical single‑dose prescriptions for individual patients [3].
5. Experimental and higher‑dose research: dose‑finding trials extend beyond labeled doses
Clinical research has explored substantially higher or multi‑day regimens for novel uses such as reducing malaria transmission; randomized dose‑finding trials have tested regimens like 300–600 mcg/kg/day for 3 days or single doses up to 800 mcg/kg in modeling, which exceed standard labeled doses and remain investigational [8]. These trials demonstrate that dosing beyond the licensed single 150–200 mcg/kg framework is being evaluated but should not be conflated with approved labeled use [8].
6. Practical translation: how tablet strengths map to weight‑based doses and real‑world limits
Because standard tablets are 3 mg, clinicians calculate the number of tablets needed to reach the weight‑based mcg/kg dose (for example, 200 mcg/kg for a 60 kg adult approximates 12 mg or four 3 mg tablets) and many prescribing guides offer tables to convert weight to tablet counts [2] [7]. Clinical references stress taking ivermectin on an empty stomach and caution about liver disease, elderly patients, and the need to avoid veterinary products; product labels and drug information pages provide these safety caveats [1] [9].
Limitations and divergent sources: the provided reporting robustly documents tablet strengths (notably 3 mg) and weight‑based labeled regimens in clinical and public‑health contexts, but does not produce a comprehensive country‑by‑country licensing matrix; specific marketed tablet strengths and exact label language vary by regulator and manufacturer beyond the U.S. Stromectol label and Indian supplier listings cited here [4] [6]. Where alternative regimens exist (mass 0.4 mg/kg, trial 600 mcg/kg/day), they are programmatic or investigational and explicitly differ from standard single‑dose labeled therapy [3] [8].