Key takeaways

  • Ivermectin is a prescription medication used to treat certain parasitic infections, but it is not approved for treating or preventing COVID-19.
  • Common side effects of ivermectin include diarrhea, nausea, dizziness, and swelling. Serious side effects can include neurological problems, severe skin reactions, and liver damage.
  • It’s important to follow your doctor’s dosage instructions for ivermectin and be aware of potential overdose symptoms, which can range from confusion and disorientation to seizures and coma.

Ivermectin is a generic prescription drug used to treat the following kinds of parasitic infections in adults and some children:

Ivermectin comes as an oral tablet. It also comes as a cream and a lotion, both of which you apply to your skin. This article only discusses side effects of the tablet form of ivermectin.

Read on to find out more about ivermectin’s side effects, also known as adverse effects.


Note: The Food and Drug Administration (FDA) has not approved ivermectin to treat or prevent COVID-19. The FDA has issued a warning statement about the dangers of taking this drug in large doses or for unapproved uses, as it may even lead to death. If you have questions about the use of ivermectin for COVID-19, talk with your doctor.

These are just a few of the more common side effects reported by people who took ivermectin in studies. These side effects can vary depending on what condition the drug is being used to treat. Talk with your doctor if side effects do not go away, get worse, or become too difficult to tolerate.

More common side effects in people taking ivermectin for strongyloidiasis include:

  • diarrhea
  • nausea
  • dizziness
  • itchiness (see “Tips for managing side effects”)

More common side effects in people taking ivermectin for onchocerciasis include:

Mild side effects have been reported with ivermectin oral tablet.

Examples of mild side effects that have been reported in people taking ivermectin for strongyloidiasis include:

  • fatigue (low energy)
  • abdominal pain
  • nausea or vomiting
  • diarrhea
  • dizziness
  • sleepiness
  • tremor
  • decreased appetite
  • constipation
  • skin rash
  • itchiness

Examples of mild side effects that have been reported in people taking ivermectin for onchocerciasis include:

  • swelling of the arms, legs, or face
  • headache
  • muscle pain
  • mild eye problems, such as swelling of the eye
  • fever
  • swollen lymph nodes
  • joint pain or swelling
  • skin rash
  • itchiness

In most cases, these side effects should be temporary. And some may be easily managed. But if you have any symptoms that are ongoing or bother you, talk with your doctor or pharmacist. Do not stop taking ivermectin unless your doctor recommends it.

Ivermectin may cause mild side effects other than the ones listed previously. See the drug’s prescribing information for details.

For more information about some of these side effects, see the “Tips for managing side effects” section.

Although most side effects of ivermectin are mild, it’s possible to develop serious side effects from this drug. The following list may not include all possible serious side effects of ivermectin. For more information, you can refer to the drug’s prescribing information.

If you develop serious side effects while taking ivermectin, call your doctor right away. If the side effects seem life threatening or you think you’re having a medical emergency, immediately call 911 or your local emergency number.

Serious side effects that have been reported include:

Note: After the FDA approves a drug, it tracks side effects of the medication. Sharing your experience helps make medication safer for everyone by giving doctors and researchers more information about how the drug works in real life. If you develop a side effect while taking ivermectin oral tablets and want to tell the FDA about it, visit MedWatch or call 800-FDA-1088.

Allergic reaction

For some people, ivermectin can cause an allergic reaction. But this side effect wasn’t reported in the drug’s studies.

In general, symptoms of an allergic reaction can be mild or serious.

What might help

If you have mild symptoms of an allergic reaction, such as a mild rash, call your doctor right away. They may suggest a treatment to manage your symptoms and can determine whether you should continue ivermectin treatment.

If you have symptoms of a severe allergic reaction, such as swelling or difficulty breathing, call 911 or your local emergency number right away. These symptoms could be life threatening and require immediate medical care.

If your doctor confirms you’ve had a serious allergic reaction to ivermectin, they may have you switch to a different treatment.

Get answers to some frequently asked questions about ivermectin’s side effects.

Does ivermectin cause kidney or cardiac side effects?

Ivermectin isn’t known to cause kidney side effects. It can cause some cardiac (heart-related) side effects, such as low blood pressure or increased heart rate. But it’s not known to cause serious cardiac-related conditions.

Note that the parasitic infections that ivermectin is used to treat can cause kidney or heart problems.

If you notice any symptoms of kidney problems, such as changes in how often you urinate, low energy, nausea, or vomiting, contact your doctor right away. They can determine what may be causing your symptoms and the best way to treat them.

Get emergency medical support right away — call 911 or a local emergency number — if you develop any symptoms of heart problems, including chest pain, difficulty breathing, or dizziness.

Can ivermectin cause long-term side effects?

Although rare, it’s possible for ivermectin to cause long-term side effects. Examples include:

  • liver damage (to learn more, see “Tips for managing side effects”)
  • neurological problems (which involve the brain or nerves), such as confusion or sleepiness
  • serious eye problems, such as loss of vision
  • joint pain or swelling

If you’re concerned about developing long-term side effects from taking ivermectin, talk with your doctor. They’ll discuss with you the benefits and risks of taking ivermectin for your condition.

Will taking too much ivermectin result in overdose symptoms?

Yes, taking too much ivermectin can cause overdose symptoms, which can be serious or even fatal.

Do not take any prescription drug, including ivermectin, unless your doctor recommends it. If your doctor prescribes this drug, be sure to follow their dosage instructions.

Also, you should not take ivermectin forms meant for animals. Ivermectin prescribed for animals is very different from ivermectin prescribed for humans. It is not safe for humans to take medications meant for animals.

Taking too much ivermectin can cause the following symptoms of overdose:

If you take too much ivermectin, contact a doctor right away. They can treat any overdose symptoms that you experience.

If you have any concerns about ivermectin and overdose, talk with your doctor or pharmacist. If you have questions or concerns about ivermectin overdose or side effects in dogs or other animals, talk with your veterinarian.

Note: The FDA has issued a warning statement about the dangers of taking this drug in large doses or for unapproved uses, as it may even lead to death.

Learn more about some of the side effects ivermectin may cause.

Liver damage

Although rare, it’s possible to develop liver damage from taking ivermectin.

In studies of people taking ivermectin for strongyloidiasis, increased levels of liver enzymes were reported. Increased liver enzyme levels may indicate liver damage.

Symptoms of liver damage include:

What might help

If you experience any symptoms of liver problems while taking ivermectin, contact your doctor. They’ll order blood tests to check whether your symptoms may be caused by liver problems. In addition, they can determine how to best treat your symptoms. In some cases, they may recommend switching from ivermectin to a different medication for your condition.

Skin rash

It’s possible to develop a skin rash from taking ivermectin. In studies of the drug, this was one of the more common side effects. In some cases, a severe rash can develop.

Symptoms of mild rash include:

  • itchiness
  • discolored skin

Symptoms of severe rash include:

What might help

If you develop a rash during your treatment with ivermectin, contact your doctor. They’ll likely want to see your rash to be sure it’s not serious. Serious skin reactions, such as toxic epidermal necrolysis and Stevens-Johnson syndrome, can also be a side effect of ivermectin.

If you have a rash from ivermectin, your doctor may be able to recommend a cream to help treat it. They’ll also monitor your rash to be sure that it doesn’t become severe.

Itchiness

You may experience itchiness during your treatment with ivermectin. Studies of the drug reported this as one of the more common side effects.

What might help

Itchiness isn’t a dangerous side effect, but it can be bothersome to some people. If you have itchiness while taking ivermectin and it’s difficult to tolerate, tell your doctor. They can recommend ways to ease this side effect. For example, they may suggest an over-the-counter treatment, such as a cream that you apply to your skin. Your doctor may also want to see the affected area(s) to be sure the itchiness is not due to a serious condition.

Keeping track of side effects

During your ivermectin treatment, consider taking notes on any side effects you’re having. You can then share this information with your doctor. This is especially helpful when you first start taking new drugs or using a combination of treatments.

Your side effect notes can include things such as:

  • what dose of the drug you were taking when you had the side effect
  • how soon you had the side effect after starting that dose
  • what your symptoms were
  • how it affected your daily activities
  • what other medications you were taking
  • any other information you feel is important

Keeping notes and sharing them with your doctor will help them learn more about how ivermectin affects you. They can then use this information to adjust your treatment plan if needed.

Before starting ivermectin, discuss your health history with your doctor. Ivermectin may not be right for you if you have certain medical conditions. Other factors may also affect whether ivermectin is a good treatment option for you. Be sure to talk with your doctor if any of the following apply to you.

Immune system conditions: Ivermectin may not work as well as it should in people with immune system problems. Before you start taking this drug, tell your doctor about any conditions you have that may affect your immune system. An example is HIV. Your doctor may recommend more doses of ivermectin to treat your condition in this case.

Allergic reaction: If you’ve had an allergic reaction to ivermectin or any of its ingredients, your doctor will likely not prescribe ivermectin. Ask them what other medications are better options for you.

Liver problems: In rare cases, ivermectin can cause liver damage or may worsen liver problems in people who have them. If you have any liver problems, tell your doctor before starting ivermectin treatment. This will help them determine whether ivermectin is a safe treatment option for you.

Loa loa infection: Rarely, people with onchocerciasis who also have loiasis (an infection caused by the parasite Loa loa) develop serious and life threatening brain inflammation following ivermectin treatment. For this reason, tell your doctor if you’ve been to areas where Loa loa is present. They’ll test whether you have Loa loa before prescribing ivermectin.

Alcohol and ivermectin

There aren’t any known interactions between ivermectin and alcohol. But drinking alcohol while taking ivermectin may increase your risk of certain side effects. Examples include:

  • nausea or vomiting
  • dizziness
  • sleepiness

If you drink alcohol, talk with your doctor about how much alcohol may be safe to consume during ivermectin treatment.

Pregnancy and breastfeeding while taking ivermectin

It’s not known whether ivermectin is safe to take during pregnancy. If you’re pregnant or planning to become pregnant, tell your doctor. They may recommend a different treatment option for your infection.

In addition, ivermectin can pass into breast milk and may cause side effects in a child who is breastfed. If you’re breastfeeding or planning to breastfeed, let your doctor know. Your doctor will determine whether ivermectin is safe for you to take during this time.

If you have any questions about the side effects that ivermectin can cause, talk with your doctor.

Disclaimer: Healthline has made every effort to make certain that all information is factually correct, comprehensive, and up to date. However, this article should not be used as a substitute for the knowledge and expertise of a licensed healthcare professional. You should always consult your doctor or another healthcare professional before taking any medication. The drug information contained herein is subject to change and is not intended to cover all possible uses, directions, precautions, warnings, drug interactions, allergic reactions, or adverse effects. The absence of warnings or other information for a given drug does not indicate that the drug or drug combination is safe, effective, or appropriate for all patients or all specific uses.