Entrectinib

Say it: en-TREK-tih-nib · Brand names: Rozlytrek

Entrectinib is a targeted therapy that blocks certain abnormal proteins made by cancers with specific gene changes.

What it is

Some cancers have a gene change called a ROS1 fusion or an NTRK fusion. These changes make proteins that keep telling the cancer cells to grow. Entrectinib blocks these proteins and can shrink the cancer, including in the brain.

Often used for

• non small cell lung cancer with a ROS1 gene change
• solid tumors with an NTRK gene change, in adults and children

How you get it

Entrectinib is taken by mouth at home, once a day, with or without food. It comes as capsules and as small pellets for people who cannot swallow capsules. Your schedule may be different.

Common side effects and what helps

• Feeling tired or weak. Rest when you need to, and try short walks.
• Constipation. Drink fluids, eat fiber, and ask your team about a stool softener.
• Changes in how food tastes. Try new flavors and keep your mouth clean.
• Swelling in your hands, feet, or ankles. Raise your legs when you sit.
• Feeling dizzy. Stand up slowly and be careful when driving.
• Diarrhea. Drink plenty of fluids. Tell your team early, since they may give you medicine to help.
• Feeling sick to your stomach or throwing up. Eat small meals and ask your team about anti-nausea medicine.
• Weight gain. Your team will keep track of your weight.

Call your care team right away if you have

• Shortness of breath, swelling in your legs, or fast weight gain
• Confusion, memory problems, mood changes, seeing or hearing things that are not there, or very bad dizziness
• Bone pain or a broken bone
• Changes in your eyesight
• Feeling faint, or a racing or uneven heartbeat
• Yellow skin or eyes, dark tea colored urine, or pain on the right side of your belly

Before you start, tell your team

• If you are pregnant, may become pregnant, or are breastfeeding
• If you have heart problems, including heart failure or an uneven heartbeat
• If you have liver problems or gout
• All the medicines, vitamins, and herbal products you take, since some can change how this medicine works

Good to know

• It can affect the brain and nerves, causing dizziness, confusion, mood changes, or sleep problems. Do not drive until you know how it affects you.
• It can cause heart failure and heart rhythm changes. Your team may check your heart.
• It can raise the chance of broken bones.
• You will have blood tests to check your liver and uric acid.
• This medicine can harm an unborn baby. Use birth control during treatment and for some time after. Ask your team how long.

At home

• Take it at the same time each day. Swallow capsules whole. Do not open, crush, or chew them.
• If you take the pellets, follow your team's directions for mixing them with soft food.
• Do not eat grapefruit or drink grapefruit juice while taking this medicine.
• If you miss a dose or throw up after taking it, ask your team what to do. Do not take extra pills to make up for it.
• Store the pills at room temperature in the original bottle, away from children and pets.

Questions to ask

• How long will I take this medicine?
• Is it safe for me to drive?
• How will we know if this medicine is working?
• Which side effects should I call about right away, and which can wait until my next visit?

Side effect guides

• Fatigue (tiredness)
• Nausea and vomiting
• Diarrhea
• Constipation
• Taste changes

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.