Key takeaways

  • Alecensa can cause a wide range of side effects. These include mild issues such as fatigue, constipation, swelling, and muscle problems to serious conditions such as liver damage, lung problems, kidney problems, and a slow heart rate.
  • This medication frequently causes changes in blood test results, including alterations in blood sugar, electrolytes, and increased creatinine or creatine phosphokinase (CPK) levels. Because of this, doctors will order frequent blood tests to monitor these levels.
  • Before starting Alecensa, be sure to talk with your doctor about any heart, lung, liver, or kidney problems you have or have had. This drug is not recommended for patients who are pregnant or breastfeeding due to potential risks to the fetus or breastfed child.

Alecensa (alectinib) is a prescription drug used in adults to:

The active ingredient in Alecensa is alectinib. The drug comes as a capsule that you swallow and should always be taken with food.

Keep reading to learn about the common, mild, and serious side effects Alecensa can cause.

Some people may experience mild to serious side effects during Alecensa treatment.

Examples of Alecensa’s commonly reported side effects include:

Mild side effects have been reported with Alecensa. These include:

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

Alecensa may cause mild side effects other than those listed here. See the drug’s prescribing information for details.

Serious side effects have been reported with Alecensa. These include:

If you develop serious side effects while taking Alecensa, 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.

Note: After the Food and Drug Administration (FDA) approves a drug, it tracks and reviews 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 Alecensa and want to tell the FDA about it, visit MedWatch or call 800-FDA-1088.

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

Changes in certain blood tests

It’s common for Alecensa to cause changes in certain blood tests. This includes tests that check your levels of:

Alecensa may cause any of the following changes:

Alecensa may also cause changes in blood tests that check your kidney function or liver function. Changes in these tests can be a sign of a kidney or liver problem which are possible serious side effects of Alecensa.

What might help

Your doctor will likely give you blood tests before you start Alecensa, every 2 weeks during the first 3 months of treatment, then once per month.

If you have symptoms of the conditions above while taking Alecensa, tell your doctor right away. They’ll likely check your blood test results and suggest ways to ease your symptoms. They’ll advise whether it’s safe for you to keep taking Alecensa or if you need a lower dosage of the drug.

Vision problems

Vision problems are a less common side effect of Alecensa. Examples of vision problems this drug may cause include:

What might help

If you’re concerned about vision problems with Alecensa, talk with your doctor. They can suggest ways to manage these side effects. They’ll also advise if it’s safe for you to keep taking Alecensa.

Allergic reaction

Like most drugs, Alecensa may cause an allergic reaction in some people, but this side effect wasn’t reported in the drug’s studies.

Symptoms can be mild or serious and can include:

  • skin rash
  • itchiness
  • 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. They may suggest a treatment to manage your symptoms. Examples include:

  • an antihistamine you swallow, such as diphenhydramine (Benadryl)
  • a product you apply to your skin, such as hydrocortisone cream

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

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 Alecensa, they may have you switch to a different treatment.

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

Does Alecensa cause hair loss?

It’s not likely. Hair loss wasn’t reported as a side effect in studies of Alecensa.

But cancer treatments other than Alecensa may cause this side effect. For example, chemotherapy drugs are known to cause hair loss.

If you’re concerned about hair loss with Alecensa or other cancer treatments you may be receiving, talk with your doctor. They can advise you on your risk of this side effect and recommend ways to manage hair loss if it happens.

Does Alecensa cause nerve damage?

It’s not likely. Nerve damage wasn’t reported as a side effect in studies of Alecensa.

But other cancer therapies are known to cause nerve damage. For example, chemotherapy may cause peripheral neuropathy. This refers to nerve damage that leads to weakness, numbness, or pain. These symptoms typically affect the arms, hands, legs, or feet.

Tell your doctor if you’re concerned about nerve damage with Alecensa or other cancer treatments. They can talk with you about your risk of this side effect and what to do if you have any symptoms of nerve damage.

Alecensa 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 starting this medication. The following items are some of the factors to consider.

Lung problems: Before taking Alecensa, be sure to tell your doctor about any lung or breathing problems you have. Alecensa may cause certain lung problems, such as swelling in your lungs or pneumonia, and these side effects could worsen your condition.

Severe muscle pain and CPK elevation: Tell your doctor if you have unexplained muscle pain, tenderness, or weakness. Alecensa commonly causes muscle pain and an increase in a blood enzyme called creatine phosphokinase (CPK). High CPK levels can be a sign of muscle damage. Because of this risk, your doctor will check your CPK levels with blood tests at least every 2 weeks for your first month of treatment and anytime you report any new muscle symptoms to them.

Breakdown of red blood cells (hemolytic anemia): Alecensa can cause hemolytic anemia. This is a serious condition where your red blood cells are destroyed faster than your body can replace them. Call your doctor right away if you develop jaundice (yellowing of your skin or the whites of your eyes), weakness, dizziness, or shortness of breath. If you have hemolytic anemia, your doctor may pause your treatment or lower your dose.

Severe liver or kidney problems: Before starting Alecensa, tell your doctor about any severe liver or kidney problems you have. Alecensa hasn’t been studied in people with these conditions, so it’s not known if this drug is safe for them. However, this drug can cause liver or kidney problems as a side effect, which may worsen an existing liver or kidney condition. Your doctor will advise you on whether Alecensa is safe for you.

Slow heart rate: Tell your doctor if you have a slow heart rate before starting Alecensa. This drug may cause a slow heart rate as a side effect, which could worsen your condition. While you’re taking this medication, your doctor will monitor your heart rate from time to time. If you have a severely slow heart rate, they may have you stop taking the drug until your heart rate increases. Or they may prescribe a drug other than Alecensa for you.

Allergic reaction. If you’ve had an allergic reaction to Alecensa or any of its ingredients, your doctor will likely not prescribe it for you. Ask them about other treatments that might be better options for you.

Alcohol and Alecensa

There aren’t any known safety issues with drinking alcohol in moderation while taking Alecensa.

But keep in mind that drinking large amounts of alcohol can damage your liver. It isn’t known whether Alecensa is safe for people with liver damage. And Alecensa may cause liver problems as a side effect, which could worsen liver damage.

If you drink alcohol, talk with your doctor about the amount that’s safe for you to drink while taking Alecensa.

Pregnancy and breastfeeding while taking Alecensa

Note: The use of binary terms such as “male” and “female” in this section reflects the language of the sources we’ve used. Unless otherwise noted, it’s unclear whether the research we reference included participants with expansive gender identities.

Alecensa and pregnancy

It’s recommended that you avoid taking Alecensa while pregnant. This drug may cause harm to a fetus if taken during pregnancy.

If you or your partner can become pregnant, you should use an effective form of birth control while taking Alecensa. Females should continue to use birth control for at least 5 weeks after their last dose of the drug. And males should continue to use birth control for at least 3 months after their last dose.

If you’re pregnant or planning a pregnancy, talk with your doctor before starting Alecensa. They may recommend a different drug for your condition.

Alecensa and breastfeeding

It’s recommended that you avoid breastfeeding while taking Alecensa. If taken while breastfeeding, the drug may pass into your breast milk and could cause side effects in a child who’s breastfed.

To be safe, you should avoid breastfeeding while taking Alecensa and for at least 1 week after your last dose.

Before starting Alecensa, tell your doctor if you’re breastfeeding or planning to breastfeed. They may discuss other treatment options with you or suggest other healthy ways to feed your child.

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.