Ribociclib/letrozole (By mouth)

Treats breast cancer.

Brand Name(s):

Kisqali Femara Co-Pack

There may be other brand names for this medicine.

When This Medicine Should Not Be Used:

This medicine is not right for everyone. Do not use it if you had an allergic reaction to ribociclib or letrozole, or if you are pregnant or breastfeeding.

How to Use This Medicine:

Tablet, Tablet

  • Take your medicine as directed. Your dose may need to be changed several times to find what works best for you.
  • Swallow the tablet whole. Do not crush, break, or chew it.
  • It is important that you take both medicines at the same time each day, preferably in the morning. Follow your doctor's instructions on when to take these medicines.
  • Your doctor may also give you luteinizing hormone-releasing hormone medicine together with this medicine.
  • Read and follow the patient instructions that come with this medicine. Talk to your doctor or pharmacist if you have any questions.
  • Missed dose: If you miss a dose or vomit after you take this medicine, do not take another dose the same day. Wait and take your next dose when you normally would.
  • Store the medicine in a closed container at room temperature, away from heat, moisture, and direct light. Store the medicine in its original package.

Drugs and Foods to Avoid:

Ask your doctor or pharmacist before using any other medicine, including over-the-counter medicines, vitamins, and herbal products.

  • Some medicines can affect how ribociclib/letrozole works. Tell your doctor if you are using any of the following:
    • Alfentanil, bepridil, boceprevir, carbamazepine, chloroquine, clarithromycin, conivaptan, cyclosporine, dihydroergotamine, ergotamine, everolimus, fentanyl, halofantrine, haloperidol, indinavir, itraconazole, ketoconazole, lopinavir/ritonavir, methadone, midazolam, moxifloxacin, nefazodone, nelfinavir, ondansetron, phenytoin, pimozide, posaconazole, quinidine, rifampin, ritonavir, saquinavir, sirolimus, St John's wort, tacrolimus, tamoxifen, or voriconazole
    • Medicine to treat heart rhythm problem (including amiodarone, disopyramide, procainamide, quinidine, sotalol)
  • Do not eat grapefruit or drink grapefruit juice while you are using this medicine.

Warnings While Using This Medicine:

  • It is not safe to take this medicine during pregnancy. It could harm an unborn baby. Tell your doctor right away if you become pregnant. If you are a woman who can bear children, your doctor may give you a pregnancy test before you start using this medicine to make sure you are not pregnant. Women should use an effective form of birth control during treatment and for at least 3 weeks after the last dose.
  • Do not breastfeed while you are using this medicine and for 3 weeks after your last dose.
  • Tell your doctor if you have kidney disease, liver disease, congestive heart failure, heart disease, heart rhythm problem, a recent heart attack, lung problems, or any type of infection.
  • This medicine may cause the following problems:
    • Interstitial lung disease or pneumonitis (can be life-threatening)
    • Serious skin reactions, including Stevens-Johnson syndrome, toxic epidermal necrolysis, or drug reaction with eosinophilia and systemic symptoms (DRESS)
    • Heart rhythm problem, including QT prolongation
    • Liver problems
  • This medicine may make you bleed, bruise, or get infections more easily. Take precautions to prevent illness and injury. Wash your hands often.
  • Medicines used to treat cancer are very strong and can have many side effects. Before receiving this medicine, make sure you understand all the risks and benefits. It is important for you to work closely with your doctor during your treatment.
  • This medicine could cause infertility. Talk with your doctor before using this medicine if you plan to have children.
  • Your doctor will do lab tests at regular visits to check on the effects of this medicine. Keep all appointments.
  • Keep all medicine out of the reach of children. Never share your medicine with anyone.

Possible Side Effects While Using This Medicine:

Call your doctor right away if you notice any of these side effects:

  • Allergic reaction: Itching or hives, swelling in your face or hands, swelling or tingling in your mouth or throat, chest tightness, trouble breathing
  • Blistering, peeling, red skin rash
  • Chest pain, trouble breathing
  • Dark urine or pale stools, nausea, vomiting, loss of appetite, stomach pain, yellow skin or eyes
  • Fainting, dizziness, lightheadedness
  • Fast, pounding, or uneven heartbeat
  • Fever, chills, cough, sore throat, body aches
  • Unusual bleeding, bruising, or weakness

If you notice these less serious side effects, talk with your doctor:

  • Back, joint, or muscle pain
  • Constipation, diarrhea
  • Hair loss
  • Headache
  • Tiredness

If you notice other side effects that you think are caused by this medicine, tell your doctor

Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088

Last Updated: 11/6/2020

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