Ribociclib and letrozole (Oral)
Medically reviewed on September 3, 2018
Commonly used brand name(s)
In the U.S.
- Kisqali Femara Co-Pack
Available Dosage Forms:
Uses For ribociclib and letrozole
Ribociclib and letrozole combination is used in postmenopausal women with hormone receptor (HR)-positive, HER-2 negative advanced or metastatic breast cancer. It belongs to the group of medicines called antineoplastics.
Ribociclib interferes with the growth of cancer cells, which are eventually destroyed. Since the growth of normal cells may also be affected by the medicine, other unwanted effects will also occur. Some of these may be serious and must be reported to your doctor.
Female hormones that occur naturally in the body can increase the growth of some breast cancers. Letrozole works by decreasing the amounts of these hormones in the body.
Ribociclib and letrozole is available only with your doctor's prescription.
Before Using ribociclib and letrozole
In deciding to use a medicine, the risks of taking the medicine must be weighed against the good it will do. This is a decision you and your doctor will make. For ribociclib and letrozole, the following should be considered:
Tell your doctor if you have ever had any unusual or allergic reaction to ribociclib and letrozole or any other medicines. Also tell your health care professional if you have any other types of allergies, such as to foods, dyes, preservatives, or animals. For non-prescription products, read the label or package ingredients carefully.
Appropriate studies have not been performed on the relationship of age to the effects of ribociclib and letrozole combination in the pediatric population. Safety and efficacy have not been established.
Appropriate studies performed to date have not demonstrated geriatric-specific problems that would limit the usefulness of ribociclib and letrozole combination in the elderly.
There are no adequate studies in women for determining infant risk when using this medication during breastfeeding. Weigh the potential benefits against the potential risks before taking this medication while breastfeeding.
Interactions with Medicines
Although certain medicines should not be used together at all, in other cases two different medicines may be used together even if an interaction might occur. In these cases, your doctor may want to change the dose, or other precautions may be necessary. When you are taking ribociclib and letrozole, it is especially important that your healthcare professional know if you are taking any of the medicines listed below. The following interactions have been selected on the basis of their potential significance and are not necessarily all-inclusive.
Using ribociclib and letrozole with any of the following medicines is not recommended. Your doctor may decide not to treat you with this medication or change some of the other medicines you take.
Using ribociclib and letrozole with any of the following medicines is usually not recommended, but may be required in some cases. If both medicines are prescribed together, your doctor may change the dose or how often you use one or both of the medicines.
- Aripiprazole Lauroxil
- Arsenic Trioxide
- Inotuzumab Ozogamicin
- Sodium Phosphate
- Sodium Phosphate, Dibasic
- Sodium Phosphate, Monobasic
- St John's Wort
Using ribociclib and letrozole with any of the following medicines may cause an increased risk of certain side effects, but using both drugs may be the best treatment for you. If both medicines are prescribed together, your doctor may change the dose or how often you use one or both of the medicines.
Interactions with Food/Tobacco/Alcohol
Certain medicines should not be used at or around the time of eating food or eating certain types of food since interactions may occur. Using alcohol or tobacco with certain medicines may also cause interactions to occur. The following interactions have been selected on the basis of their potential significance and are not necessarily all-inclusive.
Using ribociclib and letrozole with any of the following is usually not recommended, but may be unavoidable in some cases. If used together, your doctor may change the dose or how often you use ribociclib and letrozole, or give you special instructions about the use of food, alcohol, or tobacco.
- Grapefruit Juice
- Pomegranate Juice
Other Medical Problems
The presence of other medical problems may affect the use of ribociclib and letrozole. Make sure you tell your doctor if you have any other medical problems, especially:
- Angina (severe chest pain), unstable or
- Congestive heart failure or
- Electrolyte imbalance or
- Heart attack, recent or
- Heart rhythm problems (eg, long QT syndrome, slow or irregular heartbeat)–Avoid use. May cause prolongation of QT interval.
- Infection—May decrease your body's ability to fight infection.
- Liver disease—Use with caution. The effects may be increased because of slower removal of the medicine from the body.
Proper Use of ribociclib and letrozole
Medicines used to treat cancer are very strong and can have many side effects. Before receiving ribociclib and letrozole, make sure you understand all the risks and benefits. It is important for you to work closely with your doctor during your treatment.
Take ribociclib and letrozole exactly as directed by your doctor. Do not take more of it, do not take it more often, and do not take it for a longer time than your doctor ordered.
Ribociclib and letrozole comes with a patient information insert. Read and follow the instructions carefully. Ask your doctor if you have any questions.
It is important that you take both medicines at the same time each day, preferably in the morning.
Swallow the tablet whole. Do not crush, break, or chew it. You may take ribociclib and letrozole with or without food.
Do not eat grapefruit or pomegranate, or drink grapefruit or pomegranate juice while you are using ribociclib and letrozole.
The dose of ribociclib and letrozole will be different for different patients. Follow your doctor's orders or the directions on the label. The following information includes only the average doses of ribociclib and letrozole. If your dose is different, do not change it unless your doctor tells you to do so.
The amount of medicine that you take depends on the strength of the medicine. Also, the number of doses you take each day, the time allowed between doses, and the length of time you take the medicine depend on the medical problem for which you are using the medicine.
- For oral dosage form (tablets):
- For metastatic breast cancer:
- Ribociclib: 600 milligrams (mg) (three 200 mg tablets) taken as a single dose, once a day for 21 consecutive days, followed by 7 days without medicine. Your doctor may adjust your dose as needed and tolerated.
- Letrozole: 2.5 milligrams (mg) once a day for 28 days.
- Children—Use and dose must be determined by your doctor.
- For metastatic breast cancer:
If you miss a dose of ribociclib and letrozole, skip the missed dose and go back to your regular dosing schedule. Do not double doses.
If you vomit after taking your medicine, call your doctor or pharmacist for instructions.
Store the medicine in a closed container at room temperature, away from heat, moisture, and direct light. Keep from freezing.
Keep out of the reach of children.
Do not keep outdated medicine or medicine no longer needed.
Ask your healthcare professional how you should dispose of any medicine you do not use.
Store the medicine in its original package.
Precautions While Using ribociclib and letrozole
It is very important that your doctor check your progress at regular visits to make sure ribociclib and letrozole is working properly. Blood tests may be needed to check for unwanted effects.
It is unlikely that a postmenopausal woman may become pregnant. But, using ribociclib and letrozole while you are pregnant can harm your unborn baby. If you are a woman who can bear children, your doctor may give you a pregnancy test before you start using ribociclib and letrozole to make sure you are not pregnant. Use an effective form of birth control to keep from getting pregnant during treatment and for at least 3 weeks after your last dose. If you think you have become pregnant while using the medicine, tell your doctor right away.
If you plan to have children, talk with your doctor before using ribociclib and letrozole. Some men and women using ribociclib and letrozole have become infertile (unable to have children).
Contact your doctor right away if you have any changes to your heart rhythm. You might feel dizzy or faint, or you might have a fast, pounding, or uneven heartbeat. Make sure your doctor knows if you or anyone in your family has ever had a heart rhythm problem such as QT prolongation.
Check with your doctor right away if you have pain or tenderness in the upper stomach, pale stools, dark urine, loss of appetite, nausea, vomiting, or yellow eyes or skin. These could be symptoms of a serious liver problem.
Ribociclib and letrozole combination can temporarily lower the number of white blood cells in your blood, increasing the chance of getting an infection. If you can, avoid people with infections. Check with your doctor immediately if you think you are getting an infection or if you get a fever, chills, cough or hoarseness, lower back or side pain, or painful or difficult urination.
Do not take other medicines unless they have been discussed with your doctor. This includes prescription or nonprescription (over-the-counter [OTC]) medicines and herbal (eg, St. John's wort) or vitamin supplements.
Ribociclib and letrozole Side Effects
Along with its needed effects, a medicine may cause some unwanted effects. Although not all of these side effects may occur, if they do occur they may need medical attention.
Check with your doctor immediately if any of the following side effects occur:
- Black, tarry stools
- bloating or swelling of the face, arms, hands, lower legs, or feet
- bloody or cloudy urine
- decrease in height
- difficult, burning, or painful urination
- difficult or labored breathing
- frequent urge to urinate
- lower back or side pain
- pain in the back, ribs, arms, or legs
- pale skin
- sore throat
- tightness in the chest
- tingling of the hands or feet
- ulcers, sores, or white spots in the mouth
- unusual bleeding or bruising
- unusual tiredness or weakness
- unusual weight gain or loss
Some side effects may occur that usually do not need medical attention. These side effects may go away during treatment as your body adjusts to the medicine. Also, your health care professional may be able to tell you about ways to prevent or reduce some of these side effects. Check with your health care professional if any of the following side effects continue or are bothersome or if you have any questions about them:
- hair loss
- skin rash or itching
- stomach pain
- swelling or inflammation of the mouth
- trouble sleeping
Other side effects not listed may also occur in some patients. If you notice any other effects, check with your healthcare professional.
Call your doctor for medical advice about side effects. You may report side effects to the FDA at 1-800-FDA-1088.
See also: Side effects (in more detail)
Always consult your healthcare provider to ensure the information displayed on this page applies to your personal circumstances.
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More about letrozole/ribociclib
- Letrozole/ribociclib Side Effects
- During Pregnancy
- Dosage Information
- Drug Interactions
- En Español
- Drug class: antineoplastic combinations
Other brands: Kisqali Femara Co-Pack