Ribociclib is used in combination with another medication to treat a certain type of hormone receptor-positive (depends on hormones such as estrogen to grow) advanced breast cancer or if it has spread to other parts of the body in women who are close to or who have already experienced menopause (change of life; end of monthly menstrual periods).

Ribociclib is also used in combination with fulvestrant (Faslodex) to treat a certain type of hormone-receptor-positive advanced breast cancer or if it has spread to other parts of the body as an initial treatment or in people who have not been treated successfully with other treatments in women who have already experienced menopause. Ribociclib is in a class of medications called kinase inhibitors. It works by blocking the action of an abnormal protein that signals cancer cells to multiply. This helps slow or stop the spread of cancer cells.

Side Effects Of Ribociclib

Ribociclib may cause side effects. Tell your doctor if any of these symptoms are severe or do not go away:

  • diarrhea
  • constipation
  • stomach pain
  • headache
  • hair loss
  • back pain
  • rash
  • itching
  • mouth sores
  • swelling of the hands, feet, ankles, or lower legs
  • difficulty falling asleep or staying asleep

Some side effects can be serious. If you experience any of these symptoms, call your doctor immediately:

  • fever, sore throat, chills, or other signs of infection
  • rapid, irregular, or pounding heartbeat
  • difficulty breathing or shortness of breath; cough with or without mucus; or chest pain
  • dizziness
  • fainting
  • yellowing of the skin or eyes
  • dark or brown (tea-colored) urine
  • tiredness
  • loss of appetite
  • pain in the upper right side of the stomach
  • nausea
  • vomiting
  • bleeding or bruising more easily than normal

Ribociclib may cause other side effects. Call your doctor if you have any unusual problems while taking this medication.

Warnings & Precautions

Before taking ribociclib:

  • tell your doctor and pharmacist if you are allergic to ribociclib, any other medications, or any of the ingredients in ribociclib tablets. Ask your pharmacist for a list of the ingredients.
  • tell your doctor and pharmacist what other prescription and nonprescription medications, vitamins, nutritional supplements, and herbal products you are taking or plan to take. Be sure to mention any of the following: amiodarone (Nexterone, Pacerone); certain antibiotics such as clarithromycin (Biaxin, in Prevpac) and moxifloxacin (Avelox); certain antifungal medications such as itraconazole (Onmel, Sporanox), ketoconazole (Nizoral), posaconazole (Noxafil), and voriconazole (Vfend); bepridil (no longer available in U.S.); boceprevir (Victrelis, no longer available in U.S.); chloroquine (Aralen); conivaptan; cyclosporine (Gengraf, Neoral, Sandimmune); dihydroergotamine (D.H.E. 45, Migranal); disopyramide (Norpace); ergotamine (Ergomar, in Cafergot, in Migergot); everolimus (Afinitor, Zortress); fentanyl (Abstral, Actiq, Fentora, Onsolis); halofantrine (Halfan; no longer available in U.S.); haloperidol (Haldol); certain medications for human immunodeficiency virus (HIV) such as indinavir (Crixivan), lopinavir (in Kaletra), nelfinavir (Viracept), ritonavir (Norvir, in Kaletra), and saquinavir (Invirase); certain medications for seizures such as carbamazepine (Carbatrol, Equetro, Teril, others) and phenytoin (Dilantin, Phenytek); methadone (Dolophine, Methadose); nefazodone; ondansetron (intravenous); pimozide (Orap); procainamide; quinidine (in Nuedexta); rifampin (Rimactane, Rifadin, in Rifamate, in Rifater); sirolimus (Rapamune); sotalol (Betapace, Sotylize); tacrolimus (Envarsus XR, Prograf), and tamoxifen (Soltamox). Your doctor may need to change the doses of your medications or monitor you carefully for side effects. Many other medications may also interact with ribociclib, so be sure to tell your doctor about all the medications you are taking, even those that do not appear on this list.
  • tell your doctor what herbal products you are taking, especially St. John’s Wort.
  • tell your doctor if you have had a recent heart attack; or have or have ever had a slow heartbeat; a prolonged QT interval (a rare heart problem that may cause irregular heartbeat, fainting, or sudden death); abnormal levels of potassium, calcium, phosphorus, or magnesium in your blood; heart failure; or liver, kidney, or heart disease.
  • tell your doctor if you are pregnant or plan to become pregnant. You will need to take a pregnancy test before you start treatment. Use a reliable method of birth control to prevent pregnancy during your treatment and for 3 weeks after your final dose. Talk to your doctor about birth control methods that will work for you. If you become pregnant while taking ribociclib, call your doctor immediately. Ribociclib may harm the fetus.
  • tell your doctor if you are breastfeeding or plan to breastfeed. You should not breastfeed while taking ribociclib and for at least 3 weeks after your final dose.
  • if you are having surgery, including dental surgery, tell the doctor or dentist that you are taking ribociclib.

Dosage Of Ribociclib

Ribociclib comes as a tablet to take by mouth. It is usually taken with or without food once daily in the morning for the first 21 days of a 28-day cycle. Take ribociclib at around the same time every day. Follow the directions on your prescription label carefully, and ask your doctor or pharmacist to explain any part you do not understand. Take ribociclib exactly as directed. Do not take more or less of it or take it more often than prescribed by your doctor.

Swallow the tablets whole; do not split, chew, or crush them. Do not take tablets that are broken or crushed.

If you vomit after taking ribociclib, do not take another dose. Continue your regular dosing schedule.

Your doctor may decrease your dose of ribociclib or permanently or temporarily stop your treatment. This depends on how well the medication works for you and the side effects you experience. Be sure to tell your doctor how you are feeling during your treatment with ribociclib.

Ask your pharmacist or doctor for a copy of the manufacturer’s information for the patient.


Keep all appointments with your doctor and the laboratory. Your doctor will order certain lab tests before and during your treatment to check your body’s response to ribociclib. Your doctor may also order an electrocardiogram (ECG; a test that measures the electrical activity in the heart) before and during your treatment.

Do not let anyone else take your medication. Ask your pharmacist any questions you have about refilling your prescription.

It is important for you to keep a written list of all of the prescription and nonprescription (over-the-counter) medicines you are taking, as well as any products such as vitamins, minerals, or other dietary supplements. You should bring this list with you each time you visit a doctor or if you are admitted to a hospital. It is also important information to carry with you in case of emergencies.


All information has been provided courtesy of MedLinePlus from the National Library of Medicine and from the FDA.