Ivermectin (Stromectol) is an oral antiparasitic medication that works by paralyzing and killing parasites. It is FDA-approved to treat specific internal infections like strongyloidiasis (gut worms) and onchocerciasis (river blindness), but doctors also commonly prescribe it off-label for skin infestations like scabies and lice.
The Wellness Collective
What to Know About Ivermectin (Stromectol)
Reviewed by Ashley Robinson, PharmD, Pharmacy Manager for TelyRx
Table of Contents
How it works
Ivermectin works by specifically targeting the nervous system of the parasites. It attaches to special “gates” found only on the nerve and muscle cells of invertebrates.
This attachment floods the parasite’s cells with chloride ions and overloads their system, effectively shutting down their ability to send electrical signals. This process paralyzes the parasites, making them unable to move, feed, or multiply.
Because humans do not have these specific types of channels in their nerves and muscles, the medication can target the parasites with a high margin of safety.
drug facts
| Common Brands | Stromectol |
|---|---|
| Drug Class | Anthelmintic, Antiparasitic agent |
| Generic Status | Generic version of Stromectol |
| Availability | Prescription Only |
dosing
Note: Dosing information below is educational only. Your prescribing physician will determine your specific dose based on your individual health needs.
Dosing for ivermectin is typically calculated based on body weight. The dose is usually taken once with food, then repeated in 7 to 14 days. In general, the following dosing is recommended:
- 79 to 110 lbs, 9mg, 3 tablets
- 112 to 143 lbs, 12mg, 4 tablets
- 145 to 174 lbs, 15mg, 5 tablets
- 176 lbs or more, 200 mcg per kg
FDA-approved uses
- Strongyloidiasis – An infection of the intestinal tract caused by a parasitic roundworm.
- Onchocerciasis (River Blindness) – A parasitic infection of the skin and eyes caused by a worm.
common off-label uses
You may see ivermectin prescribed for uses that are not “FDA-approved.” This is a common and legal practice called “off-label” prescribing, where a doctor uses their clinical judgment to prescribe a drug for a different (but well-researched) purpose.
- Scabies – The CDC considers oral ivermectin an essential treatment for this itchy skin infestation caused by mites. It’s especially useful for severe or crusted scabies.
- Head Lice – It is also often used for difficult-to-treat cases of head lice.
side effects
Most people tolerate ivermectin well. When side effects do occur, they are usually mild.
common side effects
- Dizziness
- Nausea or diarrhea
- Mild skin rash or itching
- Fatigue
serious side effects and reactions
Serious side effects are rare, but it’s important to know what to look for if they do occur.
- Serious Neurological Effects – Severe drowsiness, confusion, loss of balance, or seizures.
- Severe Allergic Reaction (Mazzotti Reaction) – When treating river blindness, the death of parasites can cause a body-wide inflammatory reaction. Symptoms include fever, severe rash, joint pain, and swollen, tender lymph nodes.
- Signs of Drug-Induced Allergic Reaction – Hives, swelling of your face, lips, or throat, or difficulty breathing.
Call your doctor immediately if you experience any concerning or prolonged symptoms.
pharmacist tips
- Follow Dosing Instructions – Pay close attention to whether you should take your dose on an empty stomach (for gut worms) or with food (often for scabies).
- Human Use Only Doses – Never use ivermectin products intended for animals. Veterinary formulas are highly concentrated and can lead to severe poisoning, overdose, or death in humans.
- Don’t Drive Until You Know – Ivermectin can make some people feel dizzy or drowsy. Don’t drive, operate machinery, or do anything requiring full alertness until you know how the medication affects you.
- Dosing – If you are being treated for scabies, taking the second dose (1-2 weeks later) should not be skipped. It is essential to cure the infestation by killing the newly hatched mites.
- Talk About Pregnancy – Ivermectin is generally not recommended for pregnant or breastfeeding women. If you are or may become pregnant, discuss the risks and benefits thoroughly with your doctor.
drug interactions
- Warfarin (Coumadin, Jantoven) – When taking Ivermectin with warfarin, bleeding risk can increase and requires close monitoring.
- Sedatives – Ivermectin can increase the effects of other medications that cause drowsiness, such as benzodiazepines (Valium, Xanax), barbiturates, or sleep aids.
Always give your doctor and pharmacist a complete list of all your medications, vitamins, and supplements to check for potential interactions.
FAQs
What’s the difference between ivermectin pills and ivermectin cream?
Ivermectin pills (Stromectol) are an anti-parasitic taken internally to kill parasites inside your body (like worms) or under your skin (like scabies). Ivermectin cream (Soolantra) is a topical anti-inflammatory used to treat the skin condition rosacea. They are not interchangeable.
Why are there two doses for scabies?
Ivermectin is effective at killing live scabies mites, but it does not kill their eggs. The first dose kills the live mites. The second dose, taken 1-2 weeks later, is timed to kill the new mites that have hatched from the eggs in the meantime. Skipping the second dose will likely cause the infestation to return.
Is ivermectin safe?
When prescribed by a licensed provider for its intended use (parasitic infections) and taken at the correct human dose, ivermectin is generally considered safe and effective. The dangers you hear about are often linked to people taking unprescribed, high-dose veterinary formulations.
Can I drink alcohol while taking ivermectin?
It is best to avoid alcohol. Alcohol can increase the side effects of ivermectin, especially dizziness, drowsiness, or loss of coordination.
How long does ivermectin take to work?
It begins killing parasites within hours. With scabies, you may still feel itchy for 2-4 weeks after treatment, even if the mites are gone. This is a normal reaction as your body sheds the dead mites.
What happens if I miss a dose?
If you are on a multi-dose regimen (like for scabies) and you miss your second dose, contact your doctor. They will likely have you take it as soon as you remember, or they may restart the 2-dose clock to ensure the infestation is fully treated. Do not “double up” on your own.
Do I need to treat my family for scabies, even if they aren’t itchy?
Scabies is extremely contagious. The CDC recommends that all household members and other close contacts (like sexual partners) be treated at the same time as the person who has been diagnosed. It can take 4-6 weeks for symptoms (itching) to appear, so people can spread scabies before they even know they have it. Treating everyone at once prevents a cycle of re-infestation.
What cleaning do I need to do for scabies?
On the day you take your first dose, you should machine-wash all bedding, towels, and clothing you’ve used in the last 3 days in hot water and dry them on high heat. Items that can’t be washed should be sealed in a plastic bag for at least 72 hours, as the mites cannot survive that long off a human host.
Which is better for scabies: ivermectin pills or permethrin cream?
Both are excellent first-line treatments. Permethrin cream, which is applied from the neck down and left on for 8-14 hours, is effective and often tried first. Oral ivermectin is also effective and is usually preferred for widespread outbreaks, for severe (crusted) scabies, or for people who may have difficulty applying the cream thoroughly.
compare medications
Ivermectin is often a first-line treatment, but it’s not the only option. The best choice depends on your specific infection and preference.
Compared: Ivermectin, Permethrin, or Spinosad?
Ivermectin is one of several options, which differ in their form (oral vs. topical) and how they are administered.
- Ivermectin (Stromectol) – This is an oral medication taken by mouth as a tablet. When prescribed for scabies, the standard treatment is typically two doses, spaced one to two weeks apart. As an oral medication, it works systemically, circulating through the bloodstream to kill the mites.
- Permethrin 5% Cream – This is a topical medication applied directly to the skin. The standard treatment involves applying a layer of cream to the entire body from the neck down. This cream is left on the skin for a specific duration, typically 8 to 14 hours, before it is washed off.
- Spinosad (Natroba) – This is a topical suspension that is also used to treat scabies. It is applied to the entire body, from the neck down, and left on for 10 minutes before being rinsed off.
Disclaimer
Important: Information on this page is for educational purposes only. Prescribing decisions are made by independent, licensed providers. TelyRx operates technology-enabled pharmacies and a telehealth platform that connects patients with board-certified licensed providers. Prescriptions, when provider-approved and issued, are filled and shipped by TelyRx-affiliated pharmacies. We do not employ physicians or make prescribing decisions. Learn more about our editorial standards here.