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Letrozole and ribociclib

Generic name: letrozole and ribociclib [LET-roe-zol-and-RYE-boe-SYE-klib]
Brand names: Kisqali Femara Co-Pack 200 mg-2.5 mg Dose; Kisqali Femara Co-Pack 400 mg-2.5 mg Dose; Kisqali Femara Co-Pack 600 mg-2.5 mg Dose
Oral tablet (2.5–200 mg)
Class of drugs: Combinations of antineoplastics

What is Letrozole and ribociclib?

Letrozole and Ribociclib can be used in combination for the treatment of HR-positive but HER2-negative cancerous breasts.When the tumour has spread (metastatic), letrozole or ribociclib are used.The two medicines, letrozole and ribociclib, that are packaged together are different. Letrozole and ribociclib are packaged together in yellow and violet tablets.This medication guide does not list all possible uses of letrozole or ribociclib.

Side effects of Letrozole and ribociclib

If you experience symptoms of an allergic reaction, such as hives, difficulty breathing, swelling on your face or in your throat, or a severe reaction to the skin (fever or sore throat with burning eyes, skin pain or blisters, or a red or purple rash that is blistering or peeling), seek emergency medical attention.

Letrozole or ribociclib can cause serious side effects. If you experience:

  • Chest pain, cough without or with mucus, difficulty breathing
  • If you feel dizzy or faint, your heart may be pounding.
  • Liver problems: loss of appetite, right-sided abdominal pain, fatigue, easy bruising, dark urine jaundice (yellowing skin or eyes);
  • Low red blood cells (anemia)--pale or pale-coloured skin, feeling of being light-headed, shortness of breath or feeling, or cold hands or feet;
  • Low white blood cell count—fevers, sores on the lips, throats, and skin, as well as a sore throat or sore mouth—can cause difficulty breathing.

If you experience certain side effects, your cancer treatment may be halted or delayed.

Side effects common to letrozole or ribociclib include:

  • Low white blood cell infections
  • Anaemia;
  • Tiredness;
  • Nausea, vomiting, diarrhoea, constipation;
  • Headache;
  • Rash;
  • Backache
  • Hair loss.

There may be other side effects. For medical advice on side effects, call your doctor. Contacting the FDA with reports of side effects is easy by calling them directly on 1-800-FDA-1088.

Similar/related drugs

Keytruda, Arimidex, Femara, Xeloda, Ibrance, Herceptin, and Verzenio


Letrozole or ribociclib may cause serious lung or heart problems. Contact your doctor immediately if you experience chest pain or dizziness or have a fast or pounding pulse.Letrozole or ribociclib can also cause liver and blood cell problems. You should tell your doctor if there is right-sided abdominal pain, fatigue, flu symptoms, easy bleeding or bruising, dark urine, or yellowing skin or eyes.This medication may cause severe skin reactions. Seek emergency medical attention if you experience a fever, burning eyes, skin rash, blistering, or a red or purple rash.

Before you take this drug

This medicine should not be used if you have an allergy to letrozole or ribociclib.You will be tested by your doctor to ensure that you are not suffering from any conditions that would make it unsafe for you to use this medication.

Tell your doctor about any symptoms of infection, such as fever, chills, or if:

  • Heart failure, heart disease
  • A heart attack;
  • Heart rhythm problems, including slow heartbeats
  • Long qt syndrome;
  • Low levels of calcium, potassium, or magnesium
  • Liver disease.

You may need to take an additional hormone medication if you haven't gone through menopause. If you are experiencing symptoms of menopause, such as night sweats, sleep issues, or hot flushes,Before starting the treatment, you may need a negative pregnancy result.Letrozole or ribociclib can harm an unborn child. Prevent pregnancy by using effective contraception while taking this medication and for 3 weeks following your last dose. Inform your doctor immediately if you fall pregnant.Both men and women may be affected by this medicine. It is still important that women use birth control in order to avoid pregnancy, as letrozole or ribociclib can harm a baby if it does happenDo not breastfeed for 3 weeks after the last dose of this medication and while you are taking it.

How to take Letrozole and ribociclib?

Read all instructions or guides that come with your medication and follow all directions. Follow the directions on the label.Take letrozole or ribociclib at the same time every day. Letrozole and ribaciclib can be taken with or without food.The 28-day cycle of treatment includes both letrozole (ribociclib) and ribociclib. You will take ribociclib along with letrozole at the same time every day on days 1 to 21. You will only take letrozole every day for the final 7 days.Your doctor may change your dosage from time to time. Dosing instructions should be followed very closely.Do not chew or crush any tablets. Take no tablet that has been cracked or broken.Do not take a second dose if you vomit soon after taking the tablet. Do not take another dose until the next scheduled time.This medication can cause serious heart rhythm problems or lung problems. Contact your doctor immediately if you experience fast or pounding pulses, severe dizziness or difficulty breathing, or shortness of breath.If you are taking ribociclib and letrozole, your cancer treatment may be delayed.You should not stop taking the medicine or change your dosage without consulting your doctor.Keep each medication in its original container, at room temperature, and away from heat or moisture.

Details on dosage

Adult dose for breast cancer:

Letrozole 2.5 mg once daily orally during the 28-day cycle
Ribociclib: 600 mg once daily for 21 days, followed by 7 rest days for a cycle of 28 days.
Use: Endocrine therapy as the initial treatment for women who have advanced or metastatic cancer that is hormone receptor (HR), human epidermal growth factor receptor 2 (HER2), or both.

What happens if I miss the dose?

Do not take the missed dose. Use your next dose as usual. Do not take two doses in one go.

What happens if I overdose?

Call 1-800-222-1222 for poison help or seek immediate medical attention.

What should be avoided?

Grapefruit can interact with letrozole or ribociclib, causing unwanted side effects. Avoid using grapefruit products.

Interaction with other drug

At times it may not be safe to combine certain medications.Some drugs may affect the blood levels of drugs that you are taking, causing side effects or making them less effective.Letrozole, ribociclib, and other heart medications can lead to serious problems. This is especially true if you are also taking certain other drugs for asthma, infections, high blood pressure, mental illness, cancer, or HIV.Letrozole, ribociclib, and other drugs may interact with each other. These may include prescription and over-the-counter medicines, vitamins, and herbal products; this list does not encompass every possible interaction.Inform your doctor of all medications you are currently taking and those that you will stop or start using.