If you have a certain type of cancer, tumor, or seizure disorder, your doctor might suggest Afinitor (everolimus) as a treatment option for you. Along with other questions you may have about the drug, you could be wondering about its side effects.

Afinitor is a prescription medication that’s used to treat:

* In this article, we use the term ”female” to refer to someone’s sex assigned at birth. For information about the difference between sex and gender, see this article.

Another form of Afinitor, called Afinitor Disperz, is used to treat:

  • focal seizures (also called partial seizures) in adults and some children who have TSC

And both Afinitor and Afinitor Disperz are used to treat:

  • certain benign brain tumors in adults and some children

Afinitor comes as a tablet that you take by mouth. Afinitor Disperz comes as a tablet that you dissolve in water and then drink.

For more information about Afinitor, including details about its uses, see this in-depth article.

Like other drugs, Afinitor can cause mild or serious side effects. Keep reading to learn more.

Below are a few of the more common side effects reported by people who took Afinitor in studies. These side effects can vary depending on what condition the drug is treating.

Examples of Afinitor’s commonly reported side effects include:

* To learn more about this side effect, see the “Side effects explained” section below.

Keep reading to learn about Afinitor’s other possible mild and serious side effects.

Examples of mild side effects that have been reported with Afinitor include:

* To learn more about this side effect, see the “Side effects explained” section below.

In most cases, these side effects should be temporary. And some may be easily managed, too. But if you have any symptoms that are ongoing or that bother you, talk with your doctor or pharmacist. And don’t stop using Afinitor unless your doctor recommends it.

Afinitor may cause mild side effects other than the ones listed above. See the Afinitor prescribing information for details.

Note: After the Food and Drug Administration (FDA) approves a drug, it tracks side effects of the medication. If you’d like to notify the FDA about a side effect you’ve had with Afinitor, visit MedWatch.

Although rare, some people do experience serious side effects from taking Afinitor.

Serious side effects that have been reported with Afinitor include:

* To learn more about this side effect, see the “Side effects explained” section below.

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

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

Does Afinitor cause hair loss?

When taken alone, Afinitor doesn’t typically cause hair loss.

But when it’s taken together with the drug Aromasin (exemestane), hair loss has been reported as a side effect. In fact, hair loss is somewhat common in people who take these two drugs. Usually, it’s reversible once treatment ends.

If you’re concerned about hair loss while taking Afinitor, talk with your doctor.

Are side effects from Afinitor more likely with higher tablet strengths (such as 7.5 mg or 10 mg)?

It’s hard to say whether side effects from Afinitor are more likely with higher tablet strengths. Researchers in studies of Afinitor didn’t compare side effects across different tablet strengths.

But if you have side effects from taking Afinitor, lowering the dose may help treat them. It wasn’t uncommon for people taking Afinitor in studies to need a dose adjustment due to side effects.

If you’re concerned about side effects with Afinitor, talk with your doctor. Depending on the side effects you’re experiencing, your doctor may adjust your Afinitor dose. Or they may recommend you stop taking Afinitor and try a different treatment for your condition.

Do side effects of Afinitor depend on the condition I’m using it for (such as breast cancer or kidney cancer)?

Yes, side effects can vary depending on what condition Afinitor is being used to treat. But many of the drug’s side effects reported in studies were the same regardless of the condition it was used to treat.

For example, people who took Afinitor to treat certain benign brain tumors in these studies didn’t report dry mouth, nosebleeds, or swelling in their limbs. But these side effects were reported by people who took Afinitor to treat other conditions, such as advanced breast cancer or kidney cancer.

See Afinitor’s prescribing information for side effects the drug can cause listed by the condition it’s used to treat. You can also talk with your doctor or pharmacist to learn more.

Does Afinitor cause neuropathy?

No, Afinitor isn’t known to cause neuropathy (nerve damage).

Certain chemotherapy drugs, such as docetaxel (Taxotere) and vincristine, may cause nerve damage. (Chemotherapy is a type of treatment for cancer.) But this side effect hasn’t been reported with Afinitor.

If you’re concerned about nerve damage from your cancer treatment, talk with your doctor.

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

Mouth sores or swelling

Stomatitis (mouth sores or swelling) was the most commonly reported side effect in studies of Afinitor. It was reported regardless of the condition the drug was used to treat. In most cases, this side effect was mild. But it can be severe in some people.

Mouth sores or swelling are most likely to happen in the first 8 weeks of taking Afinitor.

What might help

When you start treatment with Afinitor, your doctor may also prescribe a steroid mouthwash that you’ll “swish and spit.” This helps lower your risk of sores or swelling in your mouth while taking Afinitor.

If you develop this side effect during Afinitor treatment, your doctor will likely have you stop taking Afinitor until your symptoms go away. It’s possible that they’ll prescribe a steroid mouthwash, if you haven’t already been using one, or another treatment for this side effect. They may also lower your Afinitor dose once you resume taking it.

But if your sores or swelling are severe, your doctor may have you permanently stop treatment with Afinitor.

It’s recommended that you avoid mouthwash containing alcohol, hydrogen peroxide, iodine, or thyme during Afinitor treatment. These types of mouthwash may worsen mouth sores or swelling.

Skin rash

Skin rash is a possible side effect of Afinitor. In studies, this was one of the most commonly reported side effects regardless of the condition Afinitor was used to treat. A rash that the drug causes can be severe in rare cases, though it’s mild for most people.

A rash can also be a symptom of more serious side effects that Afinitor causes, such as an infection or an allergic reaction.

What might help

If you develop a rash while taking Afinitor, contact your doctor right away. They’ll likely want to examine your rash to help determine possible causes. Once your doctor has found the cause of the rash, they’ll recommend the best ways to treat it.

Infection

Afinitor may increase your risk of infection. This was among the most common side effects reported in studies of the drug, regardless of the condition being treated. In rare cases, the infections can be serious or even fatal.

If you’ve previously had hepatitis B, taking Afinitor may reactive the virus that causes it. This can result in the return of symptoms for this condition.

Symptoms of an infection can include:

What might help

If you develop symptoms of an infection while taking Afinitor, contact your doctor right away. Because Afinitor can raise your risk of serious infection, they’ll likely want to examine your symptoms further.

If your doctor confirms that you have an infection, they may have you temporarily or permanently stop taking Afinitor. They’ll also likely prescribe treatment for your infection.

Decrease in bone marrow activity

A decrease in bone marrow activity, known as myelosuppression, is a serious potential side effect from treatment with Afinitor. With this condition, bone marrow makes fewer blood cells than usual.

In studies of Afinitor, myelosuppression affected levels of red blood cells, white blood cells, and platelets. This side effect was commonly reported in these studies, and it can be severe in rare cases.

Symptoms can differ depending on the type of blood cell affected, but common symptoms include:

  • feeling weak or tired
  • bruising or bleeding more easily than usual
  • infections that don’t go away

What might help

Before starting treatment with Afinitor, your doctor will order lab tests to check your blood cell levels. They’ll have you repeat these tests at least every 6 months during your first year of treatment with Afinitor. After that, you’ll repeat these tests at least once every year.

If they notice your blood cell levels are low, they’ll likely recommend that you either temporarily or permanently stop taking Afinitor.

Allergic reaction

Like most drugs, Afinitor can cause an allergic reaction in some people. But this wasn’t common in studies of the drug.

Symptoms can be mild or serious and can include:

  • skin rash
  • Itchiness
  • chest pain
  • flushing (temporary warmth, redness, or deepening of skin color)
  • swelling under your skin, typically in your eyelids, lips, hands, or feet
  • swelling of your mouth, tongue, or throat, which can make it hard to breathe

What might help

If you have mild symptoms of an allergic reaction, such as a mild rash, call your doctor right away. To manage your symptoms, they may suggest an over-the-counter antihistamine you take by mouth, such as Benadryl (diphenhydramine). Or they may recommend a product you apply to your skin, such as hydrocortisone cream.

If your doctor confirms you had a mild allergic reaction to Afinitor, they’ll decide if you should continue using it.

If you have symptoms of a severe allergic reaction, such as swelling or trouble 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 had a serious allergic reaction to Afinitor, they will likely have you switch to a different treatment.

Keeping track of side effects

During your Afinitor treatment, consider keeping notes on any side effects you’re having. Then, you can share this information with your doctor. This is especially helpful to do 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 drug you were taking when you had the side effect
  • how soon after starting that dose you had the side effect
  • what your symptoms were from the side effect
  • how it affected your daily activities
  • what other medications you were also taking
  • any other information you feel is important

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

Afinitor may not be right for you if you have certain medical conditions or other factors that affect your health. Talk with your doctor about your health history before you take Afinitor. The list below includes factors to consider.

Active infection. If you have an active infection before you start taking Afinitor, be sure to let your doctor know. Afinitor can weaken your immune system, which may make your infection harder to treat. Your doctor may want you to wait until your infection clears to start taking Afinitor.

Diabetes or high cholesterol. Treatment with Afinitor can cause side effects such as high blood sugar and high cholesterol. If you have diabetes or you already have high cholesterol, these conditions may worsen during Afinitor treatment. Your doctor can determine whether Afinitor is safe for you to take. If they prescribe Afinitor to you, they may monitor your blood sugar and cholesterol levels closely during treatment. This may involve getting blood drawn for lab tests.

Hepatitis B. If you’ve previously had hepatitis B, taking Afinitor may reactivate the virus that causes it. This can result in the return of symptoms for this condition. If your doctor decides to prescribe Afinitor to you, they may monitor you closely for reactivation of the hepatitis B virus.

Kidney problems. Although rare, taking Afinitor can lead to kidney problems, including kidney failure. If you already have kidney problems, you have a higher risk of this side effect. Your doctor will let you know if Afinitor is safe for you based on your kidney problems.

Liver problems. Your liver helps your body break down certain medications, including Afinitor. If you have liver problems, your body may have trouble breaking down the drug. This could increase your risk of side effects. If your doctor determines that Afinitor is safe for you to take, they’ll likely prescribe a lower dose of the drug.

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

Alcohol use and Afinitor

Alcohol isn’t known to interact with Afinitor. But alcohol could worsen certain side effects of Afinitor, including mouth sores or swelling, nausea, and diarrhea.

If you consume alcohol, ask your doctor how much is safe for you to drink while you’re taking Afinitor.

Pregnancy and breastfeeding while taking Afinitor

Your doctor will likely recommend not taking Afinitor while pregnant. This is because the drug may cause harm to a fetus.

If you’re a female* who can become pregnant, your doctor will have you take a pregnancy test before prescribing Afinitor. During Afinitor treatment, you should use an effective form of birth control. And you should continue to use birth control for 8 weeks after ending treatment.

If you’re a male* whose partner can become pregnant, you should also use an effective form of birth control during Afinitor treatment. And you should continue to use birth control for 4 weeks after ending treatment.

It’s not known whether the drug passes into human breast milk or causes side effects in a breastfed child. Your doctor will likely recommend that you avoid breastfeeding while taking Afinitor and for 2 weeks after your last dose.

If you have additional questions about Afinitor and pregnancy or breastfeeding, talk with your doctor.

* In this article, we use the terms “male” and “female” to refer to someone’s sex assigned at birth. For information about the difference between sex and gender, see this article.

Afinitor can cause side effects, but they’re usually mild in most people. While Afinitor can also cause some serious side effects, these aren’t common.

If you have questions about Afinitor’s side effects, talk with your doctor or pharmacist. Asking questions can help you get the answers you need to feel confident about your treatment. Here are a few to get you started:

  • Can other medications I take increase my risk of side effects from Afinitor?
  • How often will I need to have lab tests to check for Afinitor’s side effects?
  • Does my age increase my risk of side effects with Afinitor?

If you have breast cancer, sign up for Healthline’s online newsletter to get the latest information on treatments and advice for managing your condition.

Q:

Can treatment with Afinitor cause long-term side effects?

Anonymous

A:

Afinitor isn’t known to cause long-term side effects.

But some serious side effects of Afinitor can cause long-term problems if they aren’t quickly treated. For example, sudden kidney failure and pneumonitis (swelling in your lungs that isn’t caused by infection) can cause long-term damage. But it’s possible to prevent this damage with quick treatment of these side effects.

If you have concerns about long-term side effects from taking Afinitor, talk with your doctor.

Elizabeth Scheffel, PharmDAnswers represent the opinions of our medical experts. All content is strictly informational and should not be considered medical advice.

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.