What are the exact FDA‑label dosing instructions (mcg/kg) and retreatment intervals listed in the Stromectol prescribing information?
Executive summary
The FDA‑label prescribing information for STROMECTOL (ivermectin) specifies dosing by indication: a single oral dose of approximately 200 mcg/kg for intestinal strongyloidiasis and approximately 150 mcg/kg for onchocerciasis (river blindness) [1] [2]. The label also notes that mass‑distribution programs typically use a 12‑month dosing interval, while retreatment for individual patients may be considered at intervals as short as 3 months; additional, more frequent or suppressive regimens are discussed for complicated or extra‑intestinal disease [3] [2] [4].
1. What the label says about dose per kilogram
STROMECTOL’s FDA label presents indication‑specific, weight‑based single doses: for intestinal (nondisseminated) strongyloidiasis the evidence cited in the label is based on clinical studies in which a single ≈200 micrograms per kilogram dose cured 64–100% of infected patients [1] [4], while for onchocerciasis the recommended single dose is ≈150 mcg/kg — a dose shown in trials to markedly reduce skin microfilariae counts [1] [2]. Multiple authoritative summaries and drug references that derive from the FDA labeling echo the same numeric doses and emphasize administration as a single oral dose calculated by body weight [5] [6].
2. Retreatment intervals described on the label
The label distinguishes public‑health mass‑distribution practice from individual clinical care: in mass treatment programs the most commonly used dose interval is 12 months, whereas for individual patients retreatment may be considered at intervals as short as 3 months [3] [2]. The prescribing information further advises that repeated follow‑up and retreatment are often required for onchocerciasis because ivermectin does not kill adult Onchocerca parasites — necessitating repeated courses over time rather than a single curative shot for the adult worms [1] [2].
3. Situations where the label recommends additional or different retreatment
For complicated presentations the label does not limit clinicians to a single fixed schedule: it notes that if recrudescence of larvae is observed in strongyloidiasis, retreatment with ivermectin is indicated and that control of extra‑intestinal strongyloidiasis may be difficult, sometimes requiring several treatments at 2‑week intervals or even suppressive monthly therapy in immunocompromised patients [4] [3]. Thus, while the standard label doses are single 150 mcg/kg or 200 mcg/kg administrations, the label permits and documents shorter retreatment spacing when clinically indicated [4] [2].
4. How public‑health practice and secondary references frame those intervals
Multiple drug information sources and the label itself align: professional monographs and compendia reiterate the label’s 12‑month interval for mass programs and the possibility of individual retreatment after as little as 3 months, reflecting programmatic experience and clinical judgment rather than a single prescriptive timetable [5] [7] [8]. Clinical trial language quoted in the label underpins the dosing claims (e.g., studies of 170–200 mcg/kg showing efficacy for strongyloidiasis and trials showing microfilarial reductions after 150 mcg/kg for onchocerciasis) but also underscores that follow‑up testing is required to verify eradication [1] [9] [2].
5. What the record does not assert and where caution is required
The FDA label and supporting sources provide explicit mcg/kg figures and programmatic intervals but do not prescribe a single universal retreatment schedule for every clinical scenario; they defer to clinical follow‑up and programmatic norms for timing decisions [2] [4]. If a specific off‑label regimen (for example, particular repeated daily dosing for scabies or ivermectin for viral illnesses) is sought, that is outside the FDA STROMECTOL label summarized here and therefore not asserted in this reporting [10] [4].