Alectinib

Say it: uh-LEK-tih-nib · Brand names: Alecensa

Alectinib is a targeted pill that blocks a growth signal in lung cancers with a change in the ALK gene.

What it is

Some lung cancers have a change in a gene called ALK. This change tells cancer cells to keep growing. Alectinib blocks the ALK signal and also works well in the brain.

Often used for

• non-small cell lung cancer with an ALK gene change
• after surgery to lower the chance the cancer comes back

How you get it

It is a capsule you take by mouth twice a day with food. After surgery, it is usually taken for up to 2 years. For advanced cancer, people take it as long as it works. Your schedule may be different.

Common side effects and what helps

• Constipation. Drink plenty of fluids, eat fiber, and ask your team about a stool softener.
• Feeling tired. Rest when you need to and take short walks when you can.
• Muscle aches. Tell your team, since this can sometimes be a sign of muscle damage.
• Swelling in the legs, feet, hands, or face. Raise your legs when sitting.
• Rash. Use gentle soap and fragrance-free moisturizer.
• Sunburn more easily. Use sunscreen and wear a hat and long sleeves outside.
• Weight gain. Tell your team if it is sudden.

Call your care team right away if you have

• Yellow skin or eyes, dark urine, or pain on the right side of your belly
• New or worse cough, shortness of breath, or chest pain
• Slow heartbeat, dizziness, or feeling like you might faint
• Bad or unexplained muscle pain, soreness, or weakness
• Peeing much less than normal
• Bleeding or bruising more than usual

Before you start, tell your team

• If you have liver, lung, or kidney problems
• If you have a slow heartbeat or take medicines that slow the heart
• If you are pregnant, may become pregnant, or are breastfeeding
• All the medicines, vitamins, and herbal products you take, since some can change how this medicine works

Good to know

• You will have regular blood tests to check your liver and muscle enzymes, especially in the first few months.
• It can slow your heartbeat. Your team will check your pulse and blood pressure.
• Rarely, it causes serious lung swelling.
• This medicine can harm an unborn baby. Ask your team about birth control during treatment and for a while after.

At home

• Take it with food, at about the same times each day.
• Swallow the capsules whole. Do not open or dissolve them.
• If you miss a dose or throw up after a dose, ask your team what to do. Do not take an extra dose on your own.
• Store the pills at room temperature in their original container, away from children and pets.
• Wash your hands after touching the pills. Ask your team if others in your home should take special care.

Questions to ask

• How long will I take this medicine?
• What tests will I need, and how often?
• Are any of my other medicines, foods, or supplements a problem with this medicine?
• What should I do if I miss a dose?
• Which side effects should I call you about right away, and which can wait?

Side effect guides

• Fatigue (tiredness)
• Constipation
• Skin rash (including EGFR-inhibitor rash)

Last updated: 2026-10-27. Medically reviewed by Veli Bakalov, MD, medical oncologist (October 2026). General education from Step by Step, the patient portal of HemeOncBuddy.