Ribociclib is a targeted therapy pill that helps stop breast cancer cells from dividing. Brand names: Kisqali, Kisqali Femara Co-Pack.

What is Ribociclib used for?

hormone receptor positive, HER2 negative early breast cancer with a high chance of coming back, given with hormone therapy; hormone receptor positive, HER2 negative breast cancer that is advanced or has spread, given with hormone therapy.

What are the common side effects of Ribociclib?

Low white blood cell counts, which raise your chance of infection. Feeling sick to your stomach or throwing up. Feeling tired or weak. Diarrhea. Hair thinning. Constipation. Headache or back pain.

When should I call my care team while taking Ribociclib?

A fever of 100.4 degrees Fahrenheit (38 degrees Celsius) or higher, or chills; Feeling faint, dizzy, or a racing or uneven heartbeat; Yellow skin or eyes, dark tea colored urine, or pain on the right side of your belly; New or worse cough, chest pain, or trouble breathing; A rash with blisters, peeling skin, or sores in your mouth or eyes.

Ribociclib

Say it: rye-boh-SY-klib · Brand names: Kisqali, Kisqali Femara Co-Pack

Ribociclib is a targeted therapy pill that helps stop breast cancer cells from dividing.

What it is

Cancer cells use proteins called CDK4 and CDK6 to divide and make more cells. Ribociclib blocks these proteins. It is given with hormone therapy, and the two work better together.

Often used for

hormone receptor positive, HER2 negative early breast cancer with a high chance of coming back, given with hormone therapy
hormone receptor positive, HER2 negative breast cancer that is advanced or has spread, given with hormone therapy

How you get it

Ribociclib is a pill you take by mouth at home, once a day, with or without food. It is usually taken for 3 weeks, followed by 1 week off, and then repeated. Your schedule may be different.

Common side effects and what helps

Low white blood cell counts, which raise your chance of infection. Wash your hands often and avoid people who are sick.
Feeling sick to your stomach or throwing up. Eat small meals and ask your team about anti-nausea medicine.
Feeling tired or weak. Rest when you need to, and try short walks.
Diarrhea. Drink plenty of fluids. Tell your team early, since they may give you medicine to help.
Hair thinning. This usually grows back after treatment.
Constipation. Drink fluids and eat fiber.
Headache or back pain. Ask your team which pain medicines are safe.

Call your care team right away if you have

A fever of 100.4 degrees Fahrenheit (38 degrees Celsius) or higher, or chills
Feeling faint, dizzy, or a racing or uneven heartbeat
Yellow skin or eyes, dark tea colored urine, or pain on the right side of your belly
New or worse cough, chest pain, or trouble breathing
A rash with blisters, peeling skin, or sores in your mouth or eyes

Before you start, tell your team

If you are pregnant, may become pregnant, or are breastfeeding
If you have heart problems, including an uneven heartbeat or a heart rhythm problem called long QT
If you have liver problems
All the medicines, vitamins, and herbal products you take, since some can change how this medicine works

Good to know

It can change your heart rhythm. You will have heart tracings (ECGs) and blood tests for body salts, especially in the first months.
You will have blood tests to check your liver and blood counts.
Rarely, it can cause lung inflammation or a serious skin reaction.
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 the pills at about the same time each day, preferably in the morning.
Swallow the pills whole.
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?
When will I need heart tracings?
Is it safe to take my other medicines, vitamins, or supplements with this one?
How will we know if this medicine is working?

Side effect guides

Sources

Quick answers

What is Ribociclib?: Ribociclib is a targeted therapy pill that helps stop breast cancer cells from dividing. Brand names: Kisqali, Kisqali Femara Co-Pack.
What is Ribociclib used for?: hormone receptor positive, HER2 negative early breast cancer with a high chance of coming back, given with hormone therapy; hormone receptor positive, HER2 negative breast cancer that is advanced or has spread, given with hormone therapy.
How is Ribociclib given?: Ribociclib is a pill you take by mouth at home, once a day, with or without food. It is usually taken for 3 weeks, followed by 1 week off, and then repeated. Your schedule may be different.
What are the common side effects of Ribociclib?: Low white blood cell counts, which raise your chance of infection. Feeling sick to your stomach or throwing up. Feeling tired or weak. Diarrhea. Hair thinning. Constipation. Headache or back pain.
When should I call my care team while taking Ribociclib?: A fever of 100.4 degrees Fahrenheit (38 degrees Celsius) or higher, or chills; Feeling faint, dizzy, or a racing or uneven heartbeat; Yellow skin or eyes, dark tea colored urine, or pain on the right side of your belly; New or worse cough, chest pain, or trouble breathing; A rash with blisters, peeling skin, or sores in your mouth or eyes.

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.