Generic Name: ivermectin

Brand Name: Stromectol

Drug Class: Anthelmintics

What is ivermectin, and what is it used for?

Ivermectin is an antiworm (anthelmintic) medication used to treat intestinal strongyloidiasis and river blindness (onchocerciasis), types of diseases caused by parasitic roundworm (nematode) infestations. Ivermectin belongs to the drug class avermectins, a group of broad-spectrum antiparasitic agents, and is used off-label in the treatment of many types of worm and mite infections.

Intestinal strongyloidiasis is caused by the larvae of Strongyloides stercoralis, which are present in the soil in free form, and penetrate the skin when people come into contact with them. The larvae migrate through the bloodstream into the lungs from where they get coughed up and swallowed, and reach the intestines, to grow into adult worms and lay eggs. The eggs hatch and the newly hatched larvae are shed in the stools, but some of the larvae reenter the colon and cause auto reinfection. Strongyloidiasis is prevalent in tropical and subtropical regions of the world and is also reported during the summer months in temperate regions.

River blindness is caused by Onchocerca volvulus species of nematodes, and is transmitted by the bite of infected blackflies, a type of biting insect found near fast-flowing streams in tropical regions in Africa, a few countries in South America, and Yemen. When a blackfly bites an infected human, the larvae get into the fly, develop inside, migrate to its proboscis, and get into the next human the infected blackfly bites. The larvae mature into adults, live in fibrous nodules under the skin, mate and reproduce, and can cause blindness if they get into the eyes.

Ivermectin binds to the parasite’s nerve and muscle cell membranes and increases their permeability to chloride ions, leading to paralysis and death of the parasites. Ivermectin can kill only the intestinal stages of the Strongyloides stercoralis worms, and the larvae stage of Onchocerca volvulus, but not the adult Onchocerca worms, which have to be surgically removed from the subcutaneous tissue.

Ivermectin was developed as a veterinary anthelmintic, but is also used to treat humans as well. The two formulations are different and humans should not use the veterinary formulation, the dosage can be highly toxic to humans. The FDA has not authorized or approved ivermectin for the treatment or prevention of COVID-19 in people or animals. Current data do not show evidence of safety and efficacy of ivermectin for these indications.

Uses of ivermectin include:

FDA-approved:

Intestinal strongyloidiasis caused by Strongyloides stercoralis

Onchocerciasis/river blindness caused by Onchocerca volvulus

Off-label uses include:

Warnings

What are the side effects of ivermectin?

Common side effects of ivermectin include:

Ophthalmic reactions including:

Less common side effects of ivermectin include:

Rare side effects of ivermectin include:

Conjunctival hemorrhage (with onchocerciasis)

Loss of vision

Low blood pressure (hypotension)

Worsening of bronchial asthma

Severe skin reactions such as:

Toxic epidermal necrolysis

Stevens-Johnson syndrome

Seizures

Depression of central nervous system

Impaired coordination, balance, and speech (ataxia)

Disorientation

Confusion

Stupor

Coma

Brain damage (encephalopathy)

Liver inflammation (hepatitis)

Elevation of bilirubin

This is not a complete list of all side effects or adverse reactions that may occur from the use of this drug.

Call your doctor for medical advice about serious side effects or adverse reactions. You may also report side effects or health problems to the FDA at 1-800-FDA-1088.

Health News

What are the dosages of ivermectin?

Tablet

3 g

Adult and pediatric:

Strongyloidiasis of the Intestinal Tract

Under 15 kg: Safety and efficacy not established

15-24 kg: 3 mg orally once

25-35 kg: 6 mg orally once

36-50 kg: 9 mg orally once

51-65 kg: 12 mg orally once

66-79 kg: 15 mg orally once

Over 80 kg: 200 mcg/kg orally once

Dosing considerations

In general repeat doses are not necessary. Perform stool examinations to verify eradication of infection.

River Blindness (Onchocerciasis)

Under 15 kg: Safety and efficacy not established

15-25 kg: 3 mg orally; may repeat in 3-12 months

26-44 kg: 6 mg orally; may repeat in 3-12 months

45-64 kg: 9 mg orally; may repeat in 3-12 months

65-84 kg: 12 mg orally; may repeat in 3-12 months

85 kg and greater: 150 mcg/kg orally; may repeat in 3-12 months

Dosing considerations

Note: Does not treat adult worms (must be surgically excised)

Off-label uses

Adult:

Head Lice (Pediculosis capitis)

200 mcg/kg orally once; may require 1-2 additional doses repeated after 7 days

Blepharitis (Demodex folliculorum)

200 mcg/kg orally once as a single dose, THEN repeat dose once in 7 days

Filariasis Due to Mansonella ozzardi

6 mg orally as a single dose

Filariasis Due to Mansonella streptocera

150 mcg/kg as single dose

Scabies Due to Sarcoptes scabiel

Immunocompromised patients: 200 mcg/kg as a single dose; may repeat in 14 days if necessary

Gnathostomiasis Due to Gnathostoma spinigerum

200 mcg/kg as a single dose

Administration

Take on an empty stomach

Monitor: Stool exams (strongyloidiasis)

Overdose

What drugs interact with ivermectin?

Inform your doctor of all medications you are currently taking, who can advise you on any possible drug interactions. Never begin taking, suddenly discontinue, or change the dosage of any medication without your doctor’s recommendation.

Ivermectin has moderate interactions with at least 50 different drugs.

Ivermectin has no known mild interactions with other drugs.

The drug interactions listed above are not all of the possible interactions or adverse effects. For more information on drug interactions, visit the RxList Drug Interaction Checker.

It is important to always tell your doctor, pharmacist, or health care provider of all prescription and over-the-counter medications you use, as well as the dosage for each, and keep a list of the information. Check with your doctor or health care provider if you have any questions about the medication.

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What else should I know about ivermectin?

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Summary

Ivermectin is an antiworm (anthelmintic) medication used to treat intestinal strongyloidiasis and river blindness (onchocerciasis), types of diseases caused by parasitic roundworm (nematode) infestations. The FDA has not authorized or approved ivermectin for the treatment or prevention of COVID-19. Common side effects of ivermectin include itching, rash, hives (urticaria), skin (swelling) edema, fever, joint pain (arthralgia), inflammation of the synovial membrane on joints (synovitis), enlargement and tenderness of lymph nodes, and eye inflammation. Avoid use or use with caution if pregnant or breastfeeding.

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