Ivermectin dosage, forms, and strengths

Medically reviewed by Gerardo Sison, Pharm.D.
Licensed Pharmacist
Updated Jan 23, 2026  •  Published Jan 27, 2022
Datos Verificados
In this article:

Key takeaways

  • Ivermectin is a crucial oral medication for treating parasitic infections, including strongyloidiasis and onchocerciasis, and is often effective in a single dose or with repeated doses.

  • It remains a potential option for treating scabies and lice, although it’s not typically the first choice and isn't officially FDA-approved for these purposes.

  • Oral ivermectin is available in 3 mg tablets and is usually dosed based on body weight, never using veterinary formulations for humans.

  • Ivermectin is not approved or recommended for treating COVID-19.

  • Topical ivermectin is useful for managing rosacea and lice in cream and lotion formulations.

Ivermectin (brand name Stromectol) is an antiparasitic medication approved to treat certain parasitic infections, mainly strongyloidiasis and onchocerciasis. It is also available as a topical treatment for head lice (brand name Sklice) and rosacea (brand name Soolantra).

The standard ivermectin dosage depends on the condition being treated and a person’s weight. Most adult doses range from 0.15 to 0.25 mg/kg taken as oral tablets on an empty stomach. While the medication is labeled to be taken on an empty stomach, oral ivermectin is often taken with food for scabies.

Ivermectin forms and strengths

Ivermectin is available in the following forms and strengths:

  • Tablet: 3 mg

  • Lotion: 0.5% 

  • Cream: 1%

Check our best Ivermectin prices

Ivermectin dosage chart for humans
Indication Standard dosage
Strongyloidiasis 0.2 mg/kg in tablet form as a single dose 
Onchocerciasis 0.15 mg/kg in tablet form as a single dose
Scabies, non-crusted (off-label) 0.2 mg/kg in tablet form once, followed by a second dose 7 to 14 days later
Scabies,  crusted (off-label) 0.2 mg/kg in tablet form for 3, 5, or 7 doses, depending on the severity of symptoms
Head lice (oral therapy off-label) 0.2 mg/kg in tablet form once, followed by a second dose 9 to 10 days later, OR 0.5% lotion applied once for 10 minutes, then rinsed off 
Pubic lice (off-label) 0.2 mg/kg in tablet form once, followed by a second dose in 1 to 2 weeks
Rosacea inflammatory lesions  1% cream applied once daily to the affected area

Ivermectin dosage for adults

Oral ivermectin has been approved by the Food and Drug Administration (FDA) to treat parasitic nematode infections caused by Strongyloides and Onchocerca species. Topical ivermectin is approved for the treatment of head lice and inflammatory pustules in rosacea. Oral ivermectin is sometimes used off-label for treating other parasitic intestinal infections, scabies, and scalp or pubic lice, particularly in people who have failed or are not candidates for standard treatments. Adult dosing varies by indication.

Ivermectin dosage for strongyloidiasis 

Strongyloidiasis is an infection caused by the parasitic roundworm Strongyloides stercoralis. Infective larvae in contaminated soil can penetrate human skin and migrate to the lungs via the bloodstream. They can then travel up the airways to be swallowed down into the small intestines. There, the larvae mature into adult female worms, which lay eggs while embedded in the intestinal submucosa. Once these eggs hatch, the larvae can be passed in the stool or cause autoinfection by penetrating the intestines or the skin around the anus. 

Timely treatment is important, as an ongoing autoinfection can lead to a hyperinfection syndrome and increased spread throughout the body. Hyperinfection and dissemination can be fatal, with a mortality rate up to 90%, and are more likely to occur in people on high-dose corticosteroids. Ivermectin paralyzes the worms by blocking chloride channels in their nerve and muscle cell membranes. 

For the treatment of strongyloidiasis in adults, oral ivermectin is administered as a single 0.2 mg/kg dose, taken on an empty stomach. 

Ivermectin dosage for onchocerciasis

Onchocerciasis, more commonly known as river blindness, is a parasitic disease caused by the filarial worm Onchocerca volvulus. It is transmitted through repeated bites of infected blackflies. Once in the blood, these worms migrate to the skin, eyes, and lymphatic system, causing severe itching, skin nodules, swollen lymph nodes, and visual impairment, including permanent blindness. Ivermectin is a treatment option that may help prevent blindness and reduce the severity of skin symptoms when taken early. 

It is not uncommon for individuals with onchocerciasis to have a co-infection with the eye worm known as Loa loa. However, ivermectin should not be used for the treatment of onchocerciasis in these individuals due to a risk of fatal encephalopathy. In addition, medications used to treat filarial infections, including ivermectin, may cause a Mazzotti reaction, characterized by fever, itching, rash, and eye inflammation.

In treating onchocerciasis in adults, oral ivermectin is administered as a single 0.15 mg/kg dose, taken on an empty stomach. For resistant disease, this treatment may be repeated after three months. 

Ivermectin dosage for scabies 

Human scabies is a contagious skin condition caused by the human itch mite, Sarcoptes scabiei. These microscopic mites burrow into the upper layer of the skin, where they live and lay eggs. Scabies infestations are usually very itchy and accompanied by a pimple-like skin rash. A severe form of scabies, known as crusted scabies, occurs most often in people with weakened immune systems. Crusted scabies can develop with thick crusts of skin that contain large numbers of scabies mites and eggs. 

Scabies is spread through prolonged, direct contact with another person who has scabies, with infestations being common in crowded places such as prisons and nursing homes. Ivermectin is effective due to its ability to attack the mite’s nervous system, leading to paralysis and death of the mite. 

For non-crusted scabies in adults, ivermectin is given as a single 0.2 mg/kg dose with food. This treatment may be repeated in two weeks if symptoms persist. 

For crusted scabies in adults, ivermectin is given as a 0.2 mg/kg dose on days 1, 2, and 8, with doses on days 9 and 15 sometimes added. It is to be taken with food and used along with a topical scabicide. For severe cases, this course may continue through days 22 and 29 and be used in combination with a topical scabicide. 

RELATED: More scabies treatments and medications

Ivermectin dosage for lice 

Head lice are very common, with an estimated 6 to 12 million cases occurring each year in the United States among children ages 3 to 11, according to the Centers for Disease Control and Prevention (CDC). Pediculus humanus capitis causes head lice infestations, while pubic lice infestations (also known as phthiriasis pubis) are caused by Pthirus pubis. 

These parasitic insects pierce human skin and feed on human blood. Unlike body lice, head and pubic lice live directly on the body, where they attach to hair shafts to live, feed, and lay eggs. Head lice are spread through close head contact, while pubic lice are typically transmitted through close physical or sexual contact.

In most adult cases of head lice, topical ivermectin 0.5% lotion is applied to the scalp and left on for 10 minutes. The medication can then be rinsed off.

In adult cases of refractory head or pubic lice, oral ivermectin may be used off-label. A common dosage is 0.2 mg/kg by mouth once, followed by a second dose seven to 14 days later. Oral therapy is generally reserved for cases that have not responded to topical treatments.

RELATED: FDA approves Rx-to-OTC switch for head lice lotion

Ivermectin dosage for rosacea

Rosacea is a chronic inflammatory condition that causes facial redness, acne-like lesions, and flushing. Although there’s no cure, treatments are available to help control it. 

Ivermectin is safe and effective for treating rosacea, as demonstrated in randomized, double-blind clinical trials. Side effects were usually mild and included skin burning and skin irritation. Although the exact mechanism of action is not fully known, ivermectin is thought to have anti-inflammatory effects.

For the treatment of rosacea in adults, ivermectin 1% cream is applied to the affected areas once per day before bedtime. 

Ivermectin dosage for children

Ivermectin can be used in children for certain parasitic infections and for head lice. Oral ivermectin is dosed by body weight and is generally used in children who weigh at least 15 kg (33 lb). For head lice, topical ivermectin 0.5% lotion is approved for children 6 months of age and older.

Ivermectin dosage chart for adults and children
Indication Weight Recommended dosage
Strongyloidiasis 15-24 kg 1, 3 mg tablet as a single 3 mg dose 
25-35 kg 2, 3 mg tablets as a single 6 mg dose
36-50 kg 3, 3 mg tablets as a single 9 mg dose 
51-65 kg 4, 3 mg tablet as a single 12 mg dose
66-79 kg 5, 3 mg tablets as a single 15 mg dose
≥80 kg 0.2 mg/kg as a single dose
Onchocerciasis 15-25 kg 1, 3 mg tablet as a single 3 mg dose
26-44 kg 2, 3 mg tablets as a single 6 mg dose
45-64 kg 3, 3 mg tablets as a single 9 mg dose
65-84 kg 4, 3 mg tablets as a single 12 mg dose
≥85 kg  0.15 mg/kg as a single dose 
Pediculosis capitis  6 months of age and older, all weights  0.5% lotion applied once for 10 minutes and then rinsed off

Ivermectin dosage restrictions

Ivermectin is contraindicated in people with a known hypersensitivity or previous allergic reaction to the drug. It should also be avoided or used with caution in people with Loa loa (loiasis) co-infection, due to potential neurologic effects.

Ivermectin is not approved to treat COVID-19. Clinical trials have not shown a clear benefit, and both the Infectious Diseases Society of America and the National Institutes of Health recommend against using ivermectin for COVID-19 outside of clinical trials.

How to take ivermectin

When treating worms, an ivermectin dose should be taken on the day(s) recommended on an empty stomach with water. For scabies and other off-label uses, such as lice, oral ivermectin is often taken with food to improve absorption.

  • Take your medicine as directed. Do not take medicine that was not prescribed to you or that was prescribed for veterinary use. 

  • This medication is often administered as a single oral dose. Your healthcare provider may prescribe additional ivermectin tablets depending on the condition being treated.

  • Read and follow the instructions for this medication. Consult your healthcare provider if you have any questions about the use of ivermectin, including its dosage, contraindications, and adverse effects.

What to do if you miss a dose or take too much

If you miss a dose of ivermectin, take it as soon as you remember unless it’s almost time for your next dose. If it’s close to the next scheduled dose, skip the missed dose and take the next one on schedule. Don’t take an extra dose to make up for a missed dose unless instructed by a healthcare provider. 

If you take more ivermectin than prescribed, contact your healthcare provider or seek medical attention right away. Signs and symptoms of ivermectin overdose may include:

  • Nausea

  • Vomiting

  • Diarrhea

  • Weakness

  • Dizziness 

  • Seizures

  • Shortness of breath

  • Stomach pain 

  • Tremors

A severe overdose may cause a loss of consciousness or coma. If you suspect an overdose, call Poison Control at 1-800-222-1222 or seek emergency medical care, especially if symptoms are severe or worsening.

Ivermectin dosage FAQs

How long does it take ivermectin to work?

The effects of ivermectin work relatively quickly. For the treatment of strongyloidiasis and onchocerciasis, ivermectin is typically taken on an empty stomach. Conversely, for scabies and lice, it is typically taken with food to improve drug absorption.

How long does ivermectin stay in your system?

The half-life of ivermectin in humans is about 18 hours in adults, meaning it takes about that long for half of the drug to be cleared from the bloodstream. However, its metabolites may be detectable for up to 12 days after a dose. 

What happens if I miss a dose of ivermectin?

Typically, ivermectin is only dosed once. However, it may need to be taken multiple times in severe cases. Missing one of these doses could lead to parasitic resistance to the medication or to inadequate reduction in the parasitic load. 

What interacts with ivermectin?

Generally, ivermectin is extremely safe and well-tolerated. There is some evidence of a drug interaction when it’s taken with warfarin, as the combination may cause an increased risk of bleeding. Discuss all medications you’re taking with a healthcare provider before starting ivermectin.

Is it safe to take ivermectin during pregnancy?

Animal studies have shown that ivermectin can cause birth defects at very high doses. While there are no adequate and well-controlled trials in pregnant women, the drug's label states that it should not be used during pregnancy. 

Ivermectin is excreted in human breast milk in low concentrations. Treatment during breastfeeding should only be considered when the risks of delaying treatment are greater than the risks of harm to a newborn. 

What is the dosage of ivermectin for pets?

In cats and dogs, ivermectin is most commonly used to prevent heartworm and treat internal or external parasites, including ear mites and some forms of mange or scabies. It is typically given as a tablet, liquid, or injectable, with the dosage prescribed by a veterinarian. 

Ivermectin treatment dosing for pets:

Many veterinary uses of ivermectin are off-label, and the dosing can vary by species, breed, and condition. Always follow a veterinarian’s instructions when using ivermectin in pets.

Sources

Medically reviewed by Gerardo Sison, Pharm.D.
Licensed Pharmacist

Gerardo Sison, Pharm.D., graduated from the University of Florida. He has worked in both community and hospital settings, providing drug information and medication therapy management services. As a medical writer, he hopes to educate and empower patients to better manage their health and navigate their treatment plans.

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