Oral Ivermectin Side Effects You Should Know About

Ivermectin (Stromectol) is a life-saving medication for millions of people around the world. It’s considered an essential medication by the World Health Organization because it treats infections caused by parasites. Ivermectin also gained attention as a possible treatment for COVID-19. But it isn’t FDA-approved or recommended for this use.  

You’ll typically only take one or two doses of ivermectin for a parasitic infection. But there are still some side effects to be aware of while you’re taking it.

Ivermectin side effects at a glance

Below are mild and serious ivermectin side effects reported in clinical trials. Some side effects are more common when using ivermectin for certain types of infections.

Keep in mind that this isn’t a complete list of all possible side effects. So reach out to your healthcare team if you experience any side effects that are concerning while taking ivermectin, even if they aren’t listed below.

Mild ivermectin side effects include:

• Itchy skin

• Dizziness

• Orthostatic hypotension (low blood pressure after standing up)

• Nausea and vomiting

• Diarrhea

• Fatigue

• Constipation

• Stomach pain

• Loss of appetite

• Muscle or joint pain

• Swollen lymph nodes

• Swollen hands, feet, or lower legs

• Tremor

• Rapid heartbeat

• Increased liver enzymes

  Rare but potentially serious ivermectin side effects include:

  • Eye swelling or pain

  • Worsening of existing asthma

  • Seizures

  • Severe skin reactions

  • Neurotoxicity (symptoms can include confusion, disorientation, and coma)

  Let’s take a closer look at seven ivermectin side effects and how to manage them.

  1. Itchy skin

  In clinical trials for ivermectin, itchy skin was the most common side effect. But itchy skin is also a common symptom of the infections that ivermectin treats.

  Your itchy skin should get better once you stop taking ivermectin and your infection is fully treated. If it becomes bothersome, talk to your healthcare team. They may recommend over-the-counter (OTC) treatments, such as loratadine (Claritin) tablets or hydrocortisone cream.

  2. Dizziness

  Dizziness is also a possible ivermectin side effect. This can happen on its own, but it may also happen due to orthostatic hypotension. This is a drop in your blood pressure when changing positions, such as sitting up or standing.

  It’s best not to drive or operate machinery until you know how ivermectin affects you. If you only need one dose, you may want to take it on a day when you can stay home. Use caution when sitting up or standing, and use a wall or furniture for support if you feel dizzy when walking, to help avoid falls.

  Dizziness can also be a sign of dehydration, so be sure you’re getting enough fluids while taking ivermectin. In most cases, dizziness should resolve on its own. But if it worsens or doesn’t go away, let your prescriber know. There could be something else causing it that requires a closer look.

  3. Nausea and vomiting

  Many people experience nausea after taking ivermectin. It’s best to take ivermectin on an empty stomach, since food can affect how it’s absorbed. So you shouldn’t take it with food to lessen nausea. But it’s OK to try an OTC nausea medication, such as bismuth subsalicylate (Pepto-Bismol), to help settle your stomach. Peppermint tea, ginger lozenges, and staying hydrated can also help.

  If you throw up after taking ivermectin, contact your prescriber for guidance. You may need another dose of medication. You can also reach out if your nausea doesn’t go away or gets worse after you take ivermectin.

  4. Diarrhea

  Diarrhea is another possible ivermectin side effect. But it’s also a common symptom of the infections that ivermectin treats. Your diarrhea should resolve on its own, but it’s a good idea to drink plenty of fluids to prevent dehydration. Check with your prescriber before taking any OTC medications to manage it. 

  If your diarrhea is severe or lasts longer than 48 hours (2 days), you should seek medical care. You should also contact your healthcare team if you develop a fever or have severe abdominal pain.

  5. Constipation

  While some people develop diarrhea from ivermectin, others experience constipation. As with diarrhea, constipation should get better after your treatment is finished and your infection has been treated.

  Staying hydrated and exercising regularly can help prevent constipation. Increasing your fiber intake can also help. If needed, an OTC treatment such as polyethylene glycol (Miralax) or docusate (Colace) may help. Seek medical care if your constipation persists or you also have severe stomach pain or rectal bleeding.

  6. Swelling and joint pain

  Ivermectin may cause edema (swelling caused by excess fluid) of your face or extremities (arms, legs, and feet). You may also experience swollen lymph nodes or achy joints. These side effects are more likely if you’re taking ivermectin for onchocerciasis (river blindness).

  It’s best to let your prescriber know about any pain or swelling that occurs while you’re taking ivermectin. In some cases, these symptoms can be an early sign of a serious allergic response known as a Mazotti reaction. This reaction happens when the death of the parasites in your body over-activates your immune system. And it can be life-threatening if it isn’t treated. Your prescriber can evaluate your symptoms to help determine what’s causing them and the best treatment option for you.

  7. Severe skin reactions

  Severe skin reactions are a rare, but serious ivermectin side effect. They include:

  • Stevens-Johnson Syndrome (SJS)

  • Toxic epidermal necrolysis (TEN)

  • Drug Reaction with Eosinophilia and Systemic Symptoms (DRESS)

  One of the most common symptoms of these conditions is a sudden rash, often along with a fever and flu-like symptoms. With SJS and TENS, the skin will blister and peel, turning red or purple. With DRESS, the rash is usually red and itchy, with small bumps on the skin.

  These reactions can happen within days of taking ivermectin or weeks after taking it. Regardless of when they occur, these skin reactions require immediate medical attention. Seek emergency care for a severe skin rash that develops after taking ivermectin. It’s also a good idea to have a healthcare professional look at any skin rash that appears, in case it’s an early sign of a more severe reaction.

  Frequently asked questions

  Does ivermectin cause liver damage?

  Liver damage isn’t a likely ivermectin side effect. In some cases, ivermectin may cause an increase in liver enzymes. But this isn’t usually harmful, and levels typically return to normal once treatment is finished. There have also been reports of people developing liver damage after taking ivermectin for COVID, which isn’t an approved use of the medication.

  Does ivermectin cause weight gain?

  Weight gain wasn’t a reported ivermectin side effect in clinical studies. But keep in mind that the infections ivermectin treats can upset your stomach and cause weight loss. So once your infection has been treated, your appetite may improve, which could lead to some weight gain. In many cases, you’ll likely be regaining weight you lost while you were sick. Regular exercise and good nutrition can help prevent unwanted weight gain. But if you’re concerned about any weight changes that occur, reach out to your healthcare team for guidance.

  The bottom line

  Ivermectin (Stromectol) is a prescription tablet that treats certain parasitic infections. Common ivermectin side effects include itchy skin and dizziness. You may also experience stomach-related side effects, such as nausea, diarrhea, or constipation. When taken as prescribed for FDA-approved infections, most ivermectin side effects are mild and resolve on their own after treatment is complete.

  Rare but serious ivermectin side effects include swelling, joint pain, and severe skin reactions. Contact your prescriber if you notice these symptoms. Seek emergency care if your symptoms are severe or seem life-threatening.