What is the use of ivermectin (antiparasitic medication)?

From the Guidelines

Ivermectin should be used with caution and only for its approved indications, such as strongyloidiasis and onchocerciasis, due to potential side effects and lack of evidence for other uses. Ivermectin is an antiparasitic medication that works by paralyzing and killing parasites by affecting their nervous system through enhancing inhibitory neurotransmission 1. For human use, it's FDA-approved for treating conditions like strongyloidiasis (intestinal infection caused by roundworms) and onchocerciasis (river blindness). The typical oral dose for adults with these approved conditions ranges from 150-200 micrograms per kilogram of body weight, usually as a single dose. For strongyloidiasis, one dose is often sufficient, while river blindness may require retreatment every 6-12 months.

Some key points to consider when using ivermectin include:

• It should not be used for children who weigh less than 15 kg due to the risk of adverse drug reactions 1
• It can be used to treat crusted scabies, but combination treatment with a topical scabicide is recommended 1
• The recommended regimen for scabies treatment is ivermectin 200ug/kg orally, repeated in 2 weeks, or permethrin 5% cream applied to all areas of the body from the neck down and washed off after 8–14 hours 1
• Infants and young children should be treated with permethrin, and those aged <10 years should not be treated with lindane 1

It's essential to follow the healthcare provider's specific instructions regarding dosing and duration of treatment, and to be aware of potential side effects, which can include dizziness, nausea, diarrhea, and skin rash. Despite widespread interest in ivermectin for COVID-19 during the pandemic, major health organizations do not recommend it for this purpose due to insufficient evidence of benefit.

From the FDA Drug Label

Following oral administration of ivermectin, plasma concentrations are approximately proportional to the dose. Ivermectin is metabolized in the liver, and ivermectin and/or its metabolites are excreted almost exclusively in the feces over an estimated 12 days, with less than 1% of the administered dose excreted in the urine. The plasma half-life of ivermectin in man is approximately 18 hours following oral administration The ivermectin drug label provides information on its pharmacokinetics and pharmacodynamics.

• Key points about ivermectin include:
  • It is metabolized in the liver
  • It has a plasma half-life of approximately 18 hours
  • It is excreted almost exclusively in the feces 2

From the Research

Ivermectin Overview

• Ivermectin is a highly effective drug against animal intestinal nematodes and is used in the treatment of onchocerciasis in humans 3.
• It has been shown to be effective in the treatment of strongyloidiasis, with a parasitological cure rate of 83% compared to 38% for albendazole 3.

Treatment of Strongyloidiasis

• A study comparing the efficacy of ivermectin and albendazole in the treatment of uncomplicated strongyloidiasis found that ivermectin was significantly more effective than albendazole (P < 0.01) 3.
• Another study found that a single dose of ivermectin was as effective as multiple doses in the treatment of non-disseminated strongyloidiasis, with a response rate of 86% compared to 85% for multiple doses 4.
• The optimal dosage of ivermectin for treating strongyloidiasis ranges from 150 to 200 μg/kg 5.

Mass Administration of Ivermectin

• Mass administration of ivermectin has been shown to significantly reduce the prevalence of strongyloidiasis in endemic areas, with a reduction from 6.8% to zero in one study 6.
• The distribution of ivermectin also had a significant impact on the prevalence of trichuriasis, but not on ascariasis and hookworm infections 6.

Ivermectin in COVID-19 Treatment

• The approved dose of ivermectin alone is not the ideal dose for the treatment of COVID-19, as the concentration of ivermectin required to inhibit SARS-CoV-2 in vitro is higher than the maximum plasma concentration achieved with the approved dose 7.
• Simulations suggest that even with a high lung:plasma ratio, ivermectin is unlikely to reach the IC50 in the lungs after single oral administration of the approved dose 7.