If you have a certain thyroid or lung cancer, your doctor may prescribe Retevmo for you.

It’s a prescription drug that’s used to treat the following cancers in specific situations:

With advanced cancer, the cancer has spread near the location where it started. And with metastatic cancer, the cancer has spread to areas farther away.

To learn more about these conditions and how Retevmo is used for them, see the “What is Retevmo used for?” section below.

Retevmo basics

Retevmo comes as capsules that you’ll take by mouth.

It’s a type of drug called a RET inhibitor. Retevmo contains the active drug selpercatinib. It’s not available in a generic form.

Read on to learn about Retevmo’s side effects, uses, and more.

Costs of prescription drugs can vary depending on many factors. These factors include what your insurance plan covers and which pharmacy you use. To find current prices for Retevmo in your area, visit GoodRx.com.

If you have questions about how to pay for your prescription, talk with your doctor or pharmacist. You can also visit the Retevmo manufacturer’s website to see if it has support options.

Like most drugs, Retevmo may cause mild or serious side effects. The lists below describe some of the more common side effects that Retevmo may cause. These lists don’t include all possible side effects.

Keep in mind that side effects of a drug can depend on:

  • your age
  • other health conditions you have
  • other medications you take

Your doctor or pharmacist can tell you more about the potential side effects of Retevmo. They can also suggest ways to help reduce side effects.

Mild side effects

Here’s a short list of some of the mild side effects that Retevmo can cause. To learn about other mild side effects, talk with your doctor or pharmacist, or read Retevmo’s patient information.

Mild side effects of Retevmo that have been reported include:

Mild side effects of many drugs may go away within a few days or a couple of weeks. But if they become bothersome, talk with your doctor or pharmacist.

Serious side effects

Serious side effects from Retevmo can occur, but they aren’t common. If you have serious side effects from Retevmo, call your doctor right away. But if you think you’re having a medical emergency, call 911 or your local emergency number.

Serious side effects of Retevmo that have been reported include:

Note: Because of this risk, Retevmo is only approved to treat certain conditions in children ages 12 years and older. This is the age when bones typically stop growing. For more information about Retevmo’s uses in children, see the “What is Retevmo used for?” section below.

* For more information about this side effect, see the “Side effect focus” section just below.

Side effect focus

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

Bleeding

You may have problems with bleeding while you’re taking Retevmo. In some cases, this side effect can be life threatening. Bleeding problems were a rare but serious side effect in studies of the drug.

Keep in mind that Retevmo may cause a low level of platelets in your blood. This can increase your risk of bleeding. (Platelets are a type of blood cell that helps your blood to form clots.)

Symptoms of bleeding problems that may happen with Retevmo include:

What might help

If you have problems with bleeding while you’re taking Retevmo, tell your doctor right away. They may check the level of platelets in your blood.

If you have severe bleeding or think you’re having a medical emergency, call 911 or your local emergency number.

If you have mild bleeding, your doctor may have you stop taking Retevmo temporarily until the bleeding stops. But if you have severe bleeding, they may prescribe a drug other than Retevmo for you.

High blood pressure

You may have high blood pressure while you’re taking Retevmo. This was a common side effect in studies of the drug.

High blood pressure doesn’t usually cause symptoms unless it’s severe. You can watch for the following symptoms of severe high blood pressure while you’re taking Retevmo:

What might help

Your doctor will check your blood pressure before you start treatment with Retevmo. If your blood pressure is high, they may treat it before you start taking this drug.

Your doctor will continue to monitor your blood pressure while you’re taking Retevmo. They may have you come into their office sometimes for a blood pressure check. Or, they may have you check your blood pressure at home using a home monitor.

If you have high blood pressure while you’re taking Retevmo, your doctor may have you stop taking the drug. They’ll likely wait until your blood pressure is well-managed before having you start the drug again. Or, they may prescribe a drug other than Retevmo for you.

Tumor lysis syndrome

Tumor lysis syndrome (TLS) can occur while you’re taking Retevmo. TLS is a condition that happens when cancer cells release harmful substances into your blood.

This side effect was rare in studies of the drug.

You may have a higher risk of TLS if your tumor is large or grows quickly. You can also have an increased risk if you’re dehydrated (have a low fluid level in your body) or have kidney problems.

Symptoms of TLS can include:

What might help

If it’s not treated, TLS can cause serious heart and kidney problems. Be sure to tell your doctor right away if you have symptoms of TLS.

Before you start taking Retevmo, your doctor may order kidney function tests for you. The results of these tests will show your doctor if you have kidney problems, which can increase your risk of TLS.

To help prevent TLS, it’s important to stay hydrated while you’re taking Retevmo. Drinking plenty of water or sports drinks, such as Gatorade, can help.

Allergic reaction

Some people may have an allergic reaction to Retevmo.

Symptoms of a mild allergic reaction can include:

  • skin rash
  • itchiness
  • flushing (temporary warmth, redness, or deepening of skin color)

A more severe allergic reaction is rare but possible. Symptoms of a severe allergic reaction can include swelling under your skin, typically in your eyelids, lips, hands, or feet. They can also include swelling of your tongue, mouth, or throat, which can cause trouble breathing.

Call your doctor right away if you have an allergic reaction to Retevmo. But if you think you’re having a medical emergency, call 911 or your local emergency number.

Find answers to some commonly asked questions about Retevmo.

How does Retevmo work?

Retevmo is used to treat certain thyroid and lung cancers. It’s used to treat these cancers when they’re caused by abnormal changes in the RET gene. (For other factors that affect Retevmo’s use, see the “How is Retevmo taken?” section below.)

Cancer happens when cells in your body rapidly multiply (make more cells) and spread. Healthy cells in your body will stop multiplying when your body no longer needs them. But cancer cells keep multiplying even when your body doesn’t need them.

The RET gene is found naturally in your body. In some cases, an abnormal change in this gene may occur, causing the gene to be overactive. An overactive RET gene can cause cells to rapidly multiply, leading to cancer.

Retevmo’s mechanism of action (how it works) is to block the RET gene. So when it’s used to treat cancer caused by changes in the RET gene, Retevmo helps keep the cancer cells from growing.

For more details about how Retevmo works, visit the drug manufacturer’s website. You can also talk with your doctor or pharmacist.

Are any reviews available from people who’ve taken Retevmo?

No, the manufacturer of Retevmo hasn’t provided reviews from people who’ve taken its drug.

If you’d like to share your experience with Retevmo, visit this page. Or, call the Lilly Oncology Support Center at 866-472-8663.

Is it safe to have surgery while I’m taking Retevmo?

You may need to temporarily stop taking Retevmo if you have a planned surgery. This is because Retevmo can cause slow healing of surgical wounds (incisions or cuts that are made during surgery).

If you have an upcoming surgery, it’s important to talk with your doctor. They may suggest that you stop taking Retevmo for at least 1 week before your surgery. They may also have you stop taking the drug for at least 2 weeks after you have a major surgery.

Temporarily stopping Retevmo gives your surgical wounds time to heal. But don’t stop taking this drug unless your doctor tells you it’s safe to do so.

Your doctor will recommend the dosage of Retevmo that’s right for you. Below are commonly used dosages, but always take the dosage your doctor prescribes.

Form

Retevmo comes as capsules that you’ll take by mouth.

Recommended dosages

Your Retevmo dosage will be based on:

  • other health conditions you have, such as liver disease
  • other medications you take
  • side effects that you have
  • your body weight

You’ll take Retevmo twice a day, with 12 hours between each dose.

Questions about Retevmo’s dosage

Here are answers to a few questions about Retevmo’s dosage.

  • What if I miss a dose of Retevmo? You’ll take your missed dose of Retevmo as soon as you remember. But if it’s less than 6 hours until your next dose is scheduled, just skip the missed dose. Then take your next dose at its usual time. Don’t take any extra doses of Retevmo to make up for a missed dose. Doing so can increase your risk of side effects from the drug.
  • Will I need to take Retevmo long term? Yes, most likely. If Retevmo is working for you without causing bothersome side effects, your doctor may prescribe it long term.
  • How long does Retevmo take to work? Retevmo starts working in your body as soon as you take it. But your tumor may not stop growing until several weeks after you’ve started the drug. You likely won’t notice that Retevmo is working in your body. Your doctor will order certain tests to make sure Retevmo is working to treat your condition.

Your doctor will explain how you should take Retevmo. They’ll also explain how much to take and how often. Be sure to follow your doctor’s instructions.

Taking Retevmo

You’ll take Retevmo capsules by mouth.

Questions about taking Retevmo

Below are answers to two important questions about taking Retevmo.

  • Can Retevmo be chewed, crushed, or split? No, you shouldn’t chew, crush, or split Retevmo capsules. They should be swallowed whole. If you have trouble swallowing Retevmo, talk with your doctor or pharmacist. Also, you can try these tips for swallowing pills.
  • Should I take Retevmo with food? In most cases, you can take Retevmo with food or without it. But if you take Retevmo with a proton pump inhibitor (PPI), you’ll need to take Retevmo with food. (PPIs are drugs used to treat conditions such as acid reflux and heartburn.)
Questions for your doctor

You may have questions about Retevmo and your treatment plan. It’s important to discuss all your concerns with your doctor.

Here are a few tips that might help guide your discussion:

  • Before your appointment, write down questions such as:
    • How will Retevmo affect my body, mood, or lifestyle?
  • Bring someone with you to your appointment if doing so will help you feel more comfortable.
  • If you don’t understand something related to your condition or treatment, ask your doctor to explain it to you.

Remember, your doctor and other healthcare professionals are available to help you. And they want you to get the best care possible. So don’t be afraid to ask questions or offer feedback on treatment of your condition.

If you have a certain thyroid or lung cancer, your doctor may prescribe Retevmo for you. It’s used to treat these cancers when they’re caused by abnormal changes in the RET gene.

Thyroid and lung cancer each occur when cells in these areas grow rapidly and out of control. These cancer cells may form a tumor in the thyroid or lungs, and then spread to other areas of the body.

The RET gene is found naturally in your body. In some cases, an abnormal change in this gene happens. This change can cause the gene to be overactive, leading to cancer. Retevmo helps keep cancer cells from growing by blocking the RET gene.

Here’s a brief description of the types of cancer with changes in the RET gene that Retevmo treats:*

  • Advanced or metastatic thyroid cancer. With advanced thyroid cancer, the cancer has spread to areas of your body near your thyroid or the lymph nodes in your neck. With metastatic thyroid cancer, the cancer has spread outside of areas near your thyroid or the lymph nodes in your neck. For this purpose, Retevmo is prescribed for adults and children ages 12 years and older who:
    • need a systemic therapy (a drug that treats your whole body)
    • have thyroid cancer that didn’t get better after it was treated with radioactive iodine therapy
  • Advanced or metastatic medullary thyroid cancer (MTC). MTC is a rare type of cancer that affects certain cells in the thyroid. Retevmo is used to treat advanced or metastatic MTC in adults and children ages 12 years and older who need a systemic therapy.
  • Metastatic non-small cell lung cancer (NSCLC). With metastatic NSCLC, the cancer has spread outside of areas near your lungs or the lymph nodes near your lungs. For this purpose, Retevmo is used in adults.

* Retevmo received accelerated approval from the Food and Drug Administration (FDA) for these uses. Accelerated approval is based on information from early clinical trials. The FDA’s decision for full approval will be made after additional studies are completed.

When considering treatment with Retevmo, you should discuss a few things with your doctor. These include:

  • your overall health
  • other medical conditions you have
  • other medications you take

These factors and others are described in more detail below.

Interactions

Taking medications, vaccines, foods, and other things with a certain drug can affect how the drug works. These effects are called interactions.

Before taking Retevmo, be sure to tell your doctor about all medications you take, including prescription and over-the-counter types. Also describe any vitamins, herbs, or supplements you use. Your doctor or pharmacist can tell you about any interactions these items may cause with Retevmo.

Interactions with drugs or supplements

Retevmo can interact with several types of drugs. These drugs include:

This list does not contain all types of drugs that may interact with Retevmo. Your doctor or pharmacist can tell you more about these interactions and any others that may occur with Retevmo treatment.

Other interactions

In addition to the drugs and supplements listed above, you may need to avoid certain foods with Retevmo.

Grapefruit and grapefruit juice haven’t specifically been reported to interact with Retevmo. But it may be best to avoid them while you’re taking this drug.

This is because grapefruit can prevent your body from breaking down Retevmo as it should. This can increase the level of Retevmo in your body, making your risk of side effects from the drug higher.

To learn more about how grapefruit may interact with certain medications, read this article. Talk with your doctor if you have questions about eating certain foods with Retevmo.

Warnings

Retevmo 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 Retevmo. Factors to consider include those in the list below.

  • Blood pressure or heart problems. Tell your doctor about any blood pressure or heart problems you have before taking Retevmo. This drug can cause high blood pressure and long QT syndrome (a type of abnormal heart rhythm). If you already have blood pressure or heart conditions, you may have an increased risk of these side effects. Your doctor may prescribe treatment for long QT syndrome or high blood pressure before you take Retevmo.
  • Liver problems. Taking Retevmo can cause liver damage as a side effect. You may have a higher risk of this if you already have liver problems. Depending on how severe your liver problems are, your doctor may prescribe a dosage of Retevmo that’s lower than usual. They may also monitor you more closely than usual during Retevmo treatment. If your liver problems worsen while you’re taking Retevmo, your doctor will likely have you stop taking the medication.
  • Allergic reaction. If you’ve had an allergic reaction to Retevmo or any of its ingredients, you shouldn’t take Retevmo. Ask your doctor what other medications are better options for you.
  • Planned surgery. Retevmo can cause slow healing of surgical wounds. If you have a surgery planned, your doctor may have you stop taking Retevmo for at least 1 week before the surgery. And they may have you not take Retevmo for at least 2 weeks after a major surgery. Your doctor can recommend what you should do if you have a planned surgery while taking this drug.

Retevmo and alcohol

There aren’t any known issues with drinking alcohol while taking Retevmo. But if you drink alcohol, it’s best to talk with your doctor about an amount that’s safe for you to drink with Retevmo.

Pregnancy and breastfeeding

It may not be safe to take Retevmo during pregnancy.

To help prevent pregnancy:

  • Females* taking Retevmo should use an effective form of birth control during treatment. And they should continue using birth control for at least 1 week after their last dose of Retevmo.
  • Males* with a sexual partner who’s able to become pregnant should also use effective birth control during treatment. And they should keep using it for at least 1 week after their last dose of the drug.

It isn’t known for sure if Retevmo passes into breast milk. To be safe, you shouldn’t breastfeed while taking Retevmo or for at least 1 week after your last dose.

If you’re pregnant, breastfeeding, or planning either, talk with your doctor. They may prescribe a drug other than Retevmo for you.

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

Don’t take more Retevmo than your doctor prescribes. Taking more than this may cause serious side effects.

What to do in case you take too much Retevmo

Call your doctor if you think you’ve taken too much Retevmo. You can also call 800-222-1222 to reach the American Association of Poison Control Centers, or use its online resource. But if you have severe symptoms, immediately call 911 (or your local emergency number) or go to the nearest emergency room.

If you have a certain thyroid or lung cancer, your doctor may prescribe Retevmo for you.

Talk with your doctor or pharmacist if you have questions about taking this drug.

You may also want to ask your doctor about other lung cancer treatments. These articles may be helpful for you:

Additionally, here’s a list of questions you may want to ask your doctor about Retevmo:

  • Will Retevmo keep working to treat my cancer after I stop taking it?
  • Will Retevmo interact with any other medications I take?
  • Should I have other cancer treatments while I take Retevmo?

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.