Everolimus (Afinitor): Side Effects, Cost, and More

Everolimus (brand name: Afinitor) is used in combination with Aromasin (chemical name: exemestane) to treat postmenopausal women with advanced-stage, hormone receptor-positive, HER2-negative breast cancer. The medicine is prescribed after treatment with Femara (chemical name: letrozole) or Arimidex (chemical name: anastrozole) has stopped working.

See Afinitor prescribing information.

Everolimus is a medicine called an mTOR (mammalian target of rapamycin) inhibitor. It interferes with the protein mTOR, which helps healthy and cancer cells to divide and grow  By blocking these proteins, breast cancer cells have a harder time multiplying and surviving.  

Afinitor is prescribed with Aromasin, an aromatase inhibitor. Both medicines are pills taken by mouth. You take the pills at the same time every day, with or without food. The recommended dosage of Afinitor is 10 mg once daily, although your doctor may recommend a lower starting dose.

You keep taking Afinitor with Aromasin as long as you are getting benefits from the medicines.

Like almost all breast cancer medicines, everolimus can cause side effects, some of them serious.

The most common side effects of everolimus are:

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  mouth sores

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  infection

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  rash

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  fatigue

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  diarrhea

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  decreased appetite

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  pain in the bones, joints, and muscles

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  hot flashes

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  headache

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  insomnia

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  increased sweating

Many of our community members report mouth sores and joint pain as their most prominent side effects. Your doctor will probably prescribe a steroid mouth rinse when you start taking Afinitor in order to prevent mouth sores.

Everolimus also may cause serious side effects, including:

Lung and breathing problems: Afinitor may cause severe lung and breathing problems. Tell your doctor right away if you develop a cough, have trouble breathing or feel short of breath, or have chest pain.

Infections: Afinitor may increase the risk of bacterial, fungal, or viral infections. Afinitor may reactivate hepatitis B in some people who’ve had that disease in the past. Tell your doctor right away if you have a temperature higher than 100.5, chills, or don’t feel well.

Kidney failure: Afinitor may cause kidney failure. Your doctor will order tests to monitor your kidney function before, during, and after taking Afinitor. If you’ve had kidney or liver problems in the past or have been diagnosed with diabetes, it’s important to tell your doctor before you start taking Afinitor.

Because Afinitor is likely to be given with Aromasin, you may also experience side effects of Aromasin, such as bone and joint pain or bone weakening and breaking.

You shouldn’t take everolimus if you’re pregnant or trying to get pregnant. Exposure to everolimus could harm your unborn baby. You also should avoid breastfeeding while taking the medicine.

It is recommended that men and women who are sexually active use birth control during treatment with everolimus. Men should continue using birth control for 4 weeks after their last dose of the medicine and women should continue using birth control for 8 weeks.

Women should use birth control during treatment as well as for 8 weeks after treatment. 

 It’s important that you don’t get pregnant while you’re getting everolimus; you must use effective birth control while you’re taking it and for 8 more weeks after you stop taking it. 

Also, women who are breastfeeding or plan to breastfeed shouldn’t take everolimus. 

Members of our community discuss their experiences with Afinitor in the community forum. Here are some of their comments. Remember, it's very important to talk to your doctor about any side effects you're having and ask about ways to manage them.

“Started Afinitor and Aromasin about 8 weeks ago. Started with a cough then [sore lungs]. That seems to be better. A few days ago, I had mouth sores and joint pain in the hips. Brain fog and a bit of nausea. Trying to drink more water for the mouth sores and [get magic] mouthwash.” —perky2020

“I was on Afinitor for about 10 months and did very well. I did use the mouthwash four times a day for eight weeks and didn’t have a problem with mouth sores, so I would definitely recommend that. I did have some swelling in my feet and occasional scalp sores, but my counts were a lot better than on the Ibrance. My hair was a lot thicker and the leg cramps and neuropathy were better.” —nkb

“My rash was mostly under my arms where it was very itchy. There were also single spots on my forearms and my face.” —ForestDweller

Read more in our Afinitor discussion forum.

The cost of everolimus may vary. The price you’ll pay depends on the drug manufacturer, your health insurance provider and plan, where you live, and the pharmacy you use. 

Note: Your insurance company may require you to get prior authorization before covering Afinitor.

There are multiple copay assistance programs available for everolimus, including AmeriPharma and Teva.

Learn more about financial assistance and medicine cost-lowering tips.