What counted as cured in the strongyloidiasis studies
The DailyMed Stromectol clinical studies (setid 681888c9-af79-4b7d-ae80-c3f4f6f1effd) define strongyloidiasis cure as the absence of larvae on at least two follow-up stool examinations, three to four weeks after treatment. Concentration methods matter, because the number of larvae per gram of stool can be very low. A Baermann apparatus is the example they give.
Two controlled studies used albendazole as the comparator, at international sites where albendazole is approved for gastrointestinal strongyloidiasis. Three controlled studies, in the US and internationally, used thiabendazole. The ivermectin dose in this block was a single 170 to 200 mcg/kg. Against thiabendazole the text specifies 200 mcg/kg for one day.
The indication itself rests on comparative and open studies in which 64% to 100% of infected patients were cured after a single 200 mcg/kg dose. That range is the spread across studies. It describes those cohorts.
Activity is limited to intestinal stages of Strongyloides stercoralis. The indication is intestinal, nondisseminated disease. Feeling well the next week is not the endpoint they used.
Cure counts versus albendazole and thiabendazole
| Comparison | Ivermectin cured | Comparator cured |
|---|---|---|
| Albendazole, international | 24/26 (92%) | 12/22 (55%) |
| Albendazole, WHO study | 126/152 (83%) | 67/149 (45%) |
| Thiabendazole, international | 9/14 (64%) | 13/15 (87%) |
| Thiabendazole, US studies | 14/14 (100%) | 16/17 (94%) |
Read the cells before the summary sentence. Versus albendazole 200 mg twice daily for three days, ivermectin cured 24 of 26 patients (92%) in the international comparative study against 12 of 22 (55%), and 126 of 152 (83%) in the WHO study against 67 of 149 (45%). DailyMed calls efficacy significantly greater for Stromectol in that comparison.
Versus thiabendazole 25 mg/kg twice daily for three days, the summary says a single 200 mcg/kg ivermectin dose was as efficacious. The cells are uneven. The international study cured 9 of 14 (64%) with ivermectin and 13 of 15 (87%) with thiabendazole. The US studies cured 14 of 14 (100%) and 16 of 17 (94%). Small denominators move a percentage fast. Tolerability leaned the other way: Stromectol was better tolerated than thiabendazole in comparative work that included 37 patients on thiabendazole, and patients on Stromectol had more abdominal distention and chest discomfort than patients on albendazole.
Among 109 patients given one or two doses of 170 to 200 mcg/kg, reactions judged possibly related included dizziness and pruritus at 2.8% each, and diarrhea and nausea at 1.8% each. Mazzotti-type reactions and eye findings tied to onchocerciasis are not expected in strongyloidiasis.
Larvae that returned as late as day 106
One study in France, a non-endemic area where reinfection was not the explanation, found Strongyloides larvae in stool as long as 106 days after ivermectin. The practical instruction is at least three stool examinations spread over the three months after treatment. If larvae return, retreatment is indicated.
A single clear sample at week three can sit inside that window and still be early. The cure definition used for the table above (two exams at three to four weeks) and the French follow-up (three months) answer different worries. Week-four silence is encouraging. It does not close the file.
In immunocompromised patients, including those with HIV, adequate controlled trials have not settled an optimal repeat schedule. Several treatments about two weeks apart may be required, and cure may not be achievable. Extra-intestinal strongyloidiasis is difficult to control. Suppressive dosing about once a month has been described as sometimes helpful. Those repeats are clinical judgments on top of the single-dose chart. The chart itself is on the weight guide.
Onchocerciasis: skin counts after 150 mcg/kg
The onchocerciasis evaluation draws on clinical studies of 1,278 patients. In a double-blind, placebo-controlled study of adults with moderate to severe infection, one 150 mcg/kg dose produced an 83.2% drop in skin microfilariae at 3 days and a 99.5% drop at 3 months, geometric means. A reduction above 90% was still there at 12 months.
The indication statement points to randomized, double-blind, placebo-controlled and comparative studies in 1,427 patients in onchocerciasis-endemic parts of West Africa. The comparative drug in that program was diethylcarbamazine citrate (DEC-C). Stromectol has no activity against adult Onchocerca volvulus. Those adults live in nodules that are infrequently palpable. Surgical removal of nodules can be considered because it takes out the worms that keep making microfilariae.
Some patients showed more microfilariae in the anterior chamber of the eye at day 3, a pattern also seen with other microfilaricidal drugs. At 3 and 6 months, a larger share of Stromectol-treated patients had a fall in that eye count than patients on placebo. An open study in children ages 6 to 13 (103 patients, 17 to 41 kg) saw similar skin-count drops out to 12 months.
Skin counts can fall while the adult worms remain in nodules. Mass programs usually repeat at 12 months. An individual retreatment interval can be as short as 3 months. Weight bands for that 150 mcg/kg dose are on the parasite guide, not repeated here.
The first four days after a microfilaria kill
In 963 adults treated with 100 to 200 mcg/kg, Mazzotti reactions worsened during the first four days at these rates: pruritus 27.5%, fever 22.6%, skin involvement (edema, papular, pustular, or urticarial rash) 22.7%, inguinal lymph-node enlargement 12.6% and tenderness 13.9%, axillary enlargement 11.0% and tenderness 4.4%. DailyMed treats these as responses to dying microfilariae, the same family of reactions long described with DEC-C, plus reactions that may be from the drug itself.
Ophthalmology checks in those 963 adults looked at baseline, day 3, and months 3 and 6. Most day-3 worsening drifted back toward baseline or better by the later visits. Headache and myalgia were common during the trials regardless of whether investigators tied them to the drug (22.3% and 19.7%). Drug-related rates for those two were under 1%.
A heavy Loa loa co-infection changes the meaning of a bad few days. Serious or fatal encephalopathy has occurred, rarely, in people with onchocerciasis who also carry a lot of Loa loa, either spontaneously or after a microfilaricidal drug. Significant time in endemic parts of West or Central Africa belongs in the history taken before the tablet.
Post-marketing reports across indications include hypotension (often on standing), worsening of asthma, toxic epidermal necrolysis, Stevens-Johnson syndrome, seizures, and liver-enzyme or bilirubin rises. Neurotoxicity, including coma and death, is in the warnings even outside onchocerciasis. A bad reaction is a clinical event. The warnings do not identify a counterfeit tablet by themselves.
Shop ratings, and the virus row that is not there
Search pages titled as ivermectin reviews often mix star counts, telehealth ads, and argument threads. The studies above scored stool larvae and skin microfilariae under a protocol. A star rating does not record a Baermann exam or a 12-month skin count. A rank beside a price is a shopping placement. This review quotes no cash figure.
If the click was really about a seller, use the FDA guide to buying medicines safely from an online pharmacy and the prescription path. A licensed pharmacy and a prescription are the US frame. A no-prescription offer is a warning sign on that FDA page.
COVID-19 and other viruses do not appear in the Stromectol clinical-studies section. There is no viral cure rate, no viral dose, and no placebo arm for a respiratory virus to quote from this document. Filling that blank with a home regimen is not what these trials tested. Parasite numbers above are the evidence this URL can stand on.
Questions people ask next
What did cure mean for strongyloidiasis? No larvae on at least two stool exams, three to four weeks after the dose. Later French follow-up still asks for three exams across three months because larvae have returned as late as day 106.
Did ivermectin win every comparator cell? No. Albendazole cells favored ivermectin (92% vs 55%, 83% vs 45%). The international thiabendazole cell was 9/14 versus 13/15. The US thiabendazole cell was 14/14 versus 16/17. The summary still calls the single 200 mcg/kg dose as efficacious as the three-day thiabendazole course.
Does the onchocerciasis dose kill adult worms? No. It reduces microfilariae. Adults remain in nodules. Nodule removal can be considered for that reason. Skin counts in the placebo-controlled adult study fell 83.2% by day 3 and 99.5% by month 3 after 150 mcg/kg.
Why did some eyes look worse at day 3? Microfilariae in the anterior chamber increased in some patients at day 3, then more Stromectol patients than placebo patients showed a decrease at months 3 and 6.
What if the patient is immunocompromised? Repeated courses may be needed for intestinal strongyloidiasis, cure may be out of reach, and extra-intestinal disease is hard to control. Controlled trials have not defined one best repeat schedule.
Where is the COVID result? It is not in these studies. There is no virus efficacy row on the Stromectol clinical-studies section to review.
Are 5,000 shop ratings the same endpoint? No. Those ratings are not paired stool exams or geometric-mean skin counts. Trial figures above are the ones tied to a method.