Ivermectin Tablets: Complete Guide to Uses, Dosage, and Safety
What is Ivermectin?
Ivermectin is a drug that has changed global health since it was found in the late 1970s. It is part of a class called avermectins, which come from a natural compound made by the bacteria Streptomyces avermitilis. The discovery of ivermectin was so important that William C. Campbell and Satoshi Ōmura won the Nobel Prize in Physiology or Medicine in 2015.
This drug is mainly used to treat parasite infections in people and animals. In humans, ivermectin is approved to treat infections caused by roundworms, threadworms, and other parasites. The World Health Organization has listed ivermectin on its list of essential medicines since the 1980s, showing its key role in health care around the world.
Ivermectin comes in different forms: tablets for oral use, creams and lotions for the skin, and shots for animals. For people, the most common form is the oral tablet, often in 3mg doses. For more details on different forms, see our comparison of ivermectin forms.
The drug has been used safely in hundreds of millions of people all over the world. It has been part of large programs that give the medicine to fight river blindness and lymphatic filariasis in tropical areas. For more on this topic, read our guide on ivermectin's history and Nobel Prize.
FDA-Approved Uses
The U.S. Food and Drug Administration has approved ivermectin for several parasite diseases. For a complete overview, visit our Medical Uses category.
Intestinal Strongyloidiasis
Strongyloidiasis is an infection caused by the roundworm Strongyloides stercoralis. This parasite is common in tropical and subtropical areas. Ivermectin is the best treatment for this condition, with cure rates over 80% after one dose. Learn more about parasites treated by ivermectin.
Onchocerciasis (River Blindness)
Onchocerciasis is caused by the worm Onchocerca volvulus. Without treatment, it can cause permanent blindness. Ivermectin kills the microfilariae, or young worms, that are made by the adult worms. Treatment is usually given every 6 to 12 months.
Scabies
Oral ivermectin is approved for treating scabies, especially if people can't use creams or lotions. For detailed treatment protocols, see our scabies treatment guide.
Head Lice
Ivermectin is also approved for head lice. A single dose often works, but a second dose after 7 to 10 days may be needed.
How Ivermectin Works
Ivermectin works through a special way that targets the nervous systems of invertebrate animals. For a deep dive into the science, read our article on ivermectin's mechanism of action.
Mechanism of Action
The drug binds to channels called glutamate-gated chloride channels, which are found in nerves and muscles of worms and insects but not in humans. When ivermectin binds to these channels, they open and let in chloride ions. This causes paralysis and death of the parasite.
Pharmacokinetics
After taking it by mouth, ivermectin is well absorbed in the stomach and intestines. Its highest level in blood happens around 4 hours after taking it. For timing tips, see how to take ivermectin.
Proper Dosage Guidelines
Getting the right dose of ivermectin depends on what disease is being treated and the person's weight. For complete dosing charts, visit our Dosage & Administration category.
Weight-Based Dosing
For most parasite infections, ivermectin is given based on body weight. The usual dose is about 150 to 200 micrograms per kilogram. A 70 kg adult would get about 12 mg. See our detailed dosage guide by weight.
12mg Tablets
The standard tablet form comes in 3mg doses. For most adults, this means taking four tablets. Read more in our 12mg tablets guide.
Potential Side Effects
Like all drugs, ivermectin can cause side effects. For comprehensive safety information, visit our Safety & Side Effects category.
Common Side Effects
The most common side effects are mild: headache, dizziness, muscle ache, nausea, and diarrhea. For a complete list, see our side effects guide.
Mazzotti Reaction
When treating onchocerciasis, a reaction called the Mazzotti reaction can occur when parasites die. Symptoms include fever, headache, and joint pain.
Drug Interactions
Understanding potential drug interactions is essential for safe use. Read our complete guide on ivermectin drug interactions.
CYP3A4 Interactions
Because ivermectin is processed by the CYP3A4 enzyme, drugs that affect this enzyme can change ivermectin levels. CYP3A4 inhibitors like ketoconazole can increase levels, while inducers like rifampin can decrease them.
Special Populations
Pregnancy and Breastfeeding
Ivermectin is Pregnancy Category C. It should only be used when benefits clearly outweigh risks. For detailed information, see our guide on ivermectin in pregnancy.
Children
Ivermectin is generally not recommended for children weighing less than 15 kg. For pediatric dosing, see our pediatric safety guide.
Global Health Impact
Ivermectin has had a profound impact on global public health. Since the late 1980s, large-scale programs have distributed billions of doses in Africa, Latin America, and the Middle East. The Mectizan Donation Program has provided ivermectin free of charge since 1987.
The World Health Organization includes ivermectin on its Model List of Essential Medicines. Learn more about ivermectin's global impact.
