Ivermectin is an antiparasitic medicine that works by paralyzing and promoting the elimination of various types of parasites. It is mainly indicated for the treatment of onchocerciasis, lice, roundworm and scabies, but can also be prescribed in topical forms for roseacea.

This medication is recommended for adults and children over 5 years of age and can be found in pharmacies with a prescription (although ivermectin topical cream for lice is available over-the-counter). Dosing varies depending on the infection being treated and body weight.

Common uses

Ivermectin oral and topical formulations are approved for the treatment of:

Intestinal strongyloidiasis, which is an infection caused by the parasite Strongyloides stercoralis;
Onchocerciasis, which is an infection caused by Onchocerca volvulus, transmitted through black flies
Lice infestation, also known as pediculosis
Rosacea, a chronic skin condition associated with facial redness

Off-label uses of ivermectin also include the treatment of parasitic infections like roundworm and scabies.

How to take

The way to use ivermectin varies depending on the condition being treated.

1. Ivermectin oral tablets

Oral ivermectin tablets are available in 3 mg (also known as brand name Stromectal), 6 mg and 12 mg strengths. Dosing varies depending on the conditions to be treated:

Strongyloidiasis: 200 mcg (0,2 mg) per kilogram of weight, taken as a single oral dose with water on an empty stomach.
Onchocerciasis: 150 mcg (0,15 mg) per kilogram of weight, taken as a single oral dose with water on an empty stomach, although the doctor may reconsider another dose in 3 months.

Although it is not FDA-approved, off-label use of ivermectin can be considered for the treatment of scabies, as follows:

Classic scabies: 200 mcg (0,2 mg) per kilogram of weight, administered in two doses 7 to 14 days apart, taken with food.
Crusted scabies: 200 mcg (0,2 mg) per kilogram of weight, with total number of doses depending on infection severity (three doses can be given on days 1, 2, and 8; five doses can be given on days 1, 2, 8, 9, and 15; or seven doses can be given on days 1, 2, 8, 9, 15, 22, and 29).

The use of oral ivermectin is not recommended in children less than 15 kg or in pregnant women, as safety in these populations has not been studied.

2. Topical ivermectin

Topical forms of ivermectin are also available for the direct application on the skin or scalp. These can be used as follows:

Rosacea: 1% ivermectin cream (brand name Soolantra) is available with a prescription, and a pea-size amount is applied to affected areas of the face once a day.
Lice: 0.5% ivermectin lotion (brand name Sklice) is available over-the-counter as a single-use tube. It is applied to dried hair until the hair and scalp are fully coated, left for 10 minutes, then rinsed off with water.

When using ivermectin lotion for scalp, you should wait 24 hours before washing your hair again with shampoo.

Possible side effects

Some of the most common side effects that may occur during treatment with ivermectin are diarrhea, nausea, vomiting, generalized weakness, lack of energy, abdominal pain, loss of appetite or constipation. These reactions are generally mild and short-lived.

Allergic reactions may also occur, especially when taking ivermectin for onchocerciasis. This may present as abdominal pain, fever, itching all over the body, red spots on the skin, swelling in the eyes or eyelids and conjunctivitis.

If symptoms of allergic reactions appear, discontinue the medication immediately and seek urgent medical help or proceed to the nearest emergency room.

Can Ivermectin cause medicinal hepatitis?

Medication leaflets for ivermectin does not mention any serious side effects related to liver problems nor drug-induced hepatitis, however it is known that this medication can increase liver enzyme levels.

This medicine is only indicated in acute cases for short-term treatment. Taking this medication in high doses or for prolonged periods has not been studied, and the effects are unknown.

It is possible that prolonged, very frequent use or in doses higher than those indicated may cause liver problems, including drug-induced hepatitis. Ideally, you should only take ivermectin as prescribed by a doctor.

Contraindications for use

This medication is contraindicated for pregnant women, women who are breastfeeding, children under 5 years old, children weighing less than 15 kg and people with meningitis or asthma.

It should also not be used in people who are allergic to ivermectin or any other of the components present in the formula.

Ivermectin is contraindicated for people using barbiturates, benzodiazepines, valproic acid or sodium oxybate.