What is the most important information I should know about letrozole and ribociclib?
This medicine can cause a serious heart rhythm problem. Call your doctor at once if you have fast or pounding heartbeats and severe dizziness.
Letrozole and ribociclib may also affect your liver or blood cells. Tell your doctor if you have right-sided stomach pain, tiredness, easy bruising or bleeding, dark urine, and jaundice (yellowing of the skin or eyes).
You will need frequent medical tests while taking letrozole and ribociclib. Your cancer treatments may be delayed based on the results of these tests.
Other serious side effects of this medicine include fever, chills, and flu symptoms.
What is letrozole and ribociclib?
Letrozole lowers estrogen levels, which may slow the growth of certain types of breast tumors that need estrogen to grow in the body.
Ribociclib interferes with the growth and spread of cancer cells in the body.
Letrozole and ribociclib are used together in combination to treat HR-positive, HER2-negative breast cancer in women.
This medicine is used when the cancer has spread to other parts of the body (metastatic).
Letrozole and ribociclib are two different medicines that are packaged together. Letrozole tablets are yellow and ribociclib tablets are violet.
Letrozole and ribociclib may also be used for purposes not listed in this medication guide.
What should I discuss with my healthcare provider before taking letrozole and ribociclib?
You should not use this medicine if you are allergic to letrozole (Femara) or ribociclib (Kisqali).
Your doctor will perform medical tests to make sure you do not have conditions that would prevent you from safely using this medicine.
Tell your doctor if you have any signs of infection, such as fever or chills, or if you have ever had:
- heart disease, heart failure;
- a heart attack;
- heart rhythm problems, including slow heartbeats;
- long QT syndrome;
- low levels of calcium, phosphorus, potassium, or magnesium in your blood; or
- liver or kidney disease.
If you have not gone through menopause, you may need an additional hormonal medication while taking letrozole and ribociclib. Tell your doctor if you have begun having symptoms of menopause such as irregular menstrual periods, hot flashes, night sweats, sleep problems, or vaginal dryness.
You may need to have a negative pregnancy test before starting this treatment.
Letrozole and ribociclib may harm an unborn baby. Use effective birth control to prevent pregnancy while you are using this medicine and for at least 3 weeks after your last dose. Tell your doctor right away if you become pregnant.
This medicine may affect fertility (ability to have children) in both men and women. However, it is important for women to use birth control to prevent pregnancy because letrozole and ribociclib may harm the baby if a pregnancy does occur.
You should not breast-feed while using this medicine and for at least 3 weeks after your last dose.
How should I take letrozole and ribociclib?
Follow all directions on your prescription label and read all medication guides or instruction sheets. Use the medicine exactly as directed.
It is best to take this medicine in the morning, but take it at the same time each day. You may take letrozole and ribociclib with or without food.
Letrozole and ribociclib is given in a 28-day treatment cycle. On days 1 through 21, you will take both ribociclib and letrozole together at the same time each day. During the last 7 days you will take only letrozole each day.
Your doctor may occasionally change the number of tablets in your dose. Follow all dosing instructions very carefully.
Swallow each tablet whole and do not crush, chew, or break it. Do not take any tablet that is broken or cracked.
If you vomit shortly after taking a tablet, do not take another dose. Wait until your next scheduled dose time to take the medicine again.
This medicine can cause a serious heart rhythm problem. Call your doctor at once if you have a fast or pounding heartbeats and severe dizziness.
You will need frequent medical tests while taking letrozole and ribociclib. Your cancer treatments may be delayed based on the results of these tests.
Do not change your dose or stop taking this medicine without your doctor's advice.
Store each medicine in its original container at room temperature, away from moisture and heat.
What happens if I miss a dose?
Skip the missed dose and use your next dose at the regular time. Do not use two doses at one time.
What happens if I overdose?
Seek emergency medical attention or call the Poison Help line at 1-800-222-1222.
What should I avoid while taking letrozole and ribociclib?
Grapefruit may interact with letrozole and ribociclib and lead to unwanted side effects. Avoid the use of grapefruit products.
What are the possible side effects of letrozole and ribociclib?
Get emergency medical help if you have signs of an allergic reaction: hives; difficult breathing; swelling of your face, lips, tongue, or throat.
Call your doctor at once if you have:
- fast or pounding heartbeats, fluttering in your chest, shortness of breath, and sudden dizziness (like you might pass out);
-
liver problems --loss of appetite, right-sided stomach pain, tiredness, easy bruising or bleeding, dark urine, jaundice (yellowing of the skin or eyes); or
-
low white blood cell counts --fever, mouth sores, skin sores, sore throat, cough, trouble breathing.
Your cancer treatments may be delayed or permanently discontinued if you have certain side effects.
Common side effects may include:
- nausea, vomiting, diarrhea, constipation;
- headache;
- feeling tired;
- abnormal liver function tests;
- back pain; or
- hair loss.
This is not a complete list of side effects and others may occur. Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088.
What other drugs will affect letrozole and ribociclib?
Sometimes it is not safe to use certain medications at the same time. Some drugs can affect your blood levels of other drugs you take, which may increase side effects or make the medications less effective.
Letrozole and ribociclib can cause a serious heart problem. Your risk may be higher if you also use certain other medicines for infections, asthma, heart problems, high blood pressure, depression, mental illness, cancer, malaria, or HIV.
Many drugs can affect letrozole and ribociclib. This includes prescription and over-the-counter medicines, vitamins, and herbal products. Not all possible interactions are listed here. Tell your doctor about all your current medicines and any medicine you start or stop using.
Where can I get more information?
Your pharmacist can provide more information about letrozole and ribociclib.
Remember, keep this and all other medicines out of the reach of children, never share your medicines with others, and use this medication only for the indication prescribed.
Every effort has been made to ensure that the information provided by Cerner Multum, Inc. ('Multum') is accurate, up-to-date, and complete, but no guarantee is made to that effect. Drug information contained herein may be time sensitive. Multum information has been compiled for use by healthcare practitioners and consumers in the United States and therefore Multum does not warrant that uses outside of the United States are appropriate, unless specifically indicated otherwise. Multum's drug information does not endorse drugs, diagnose patients or recommend therapy. Multum's drug information is an informational resource designed to assist licensed healthcare practitioners in caring for their patients and/or to serve consumers viewing this service as a supplement to, and not a substitute for, the expertise, skill, knowledge and judgment of healthcare practitioners. The absence of a warning for a given drug or drug combination in no way should be construed to indicate that the drug or drug combination is safe, effective or appropriate for any given patient. Multum does not assume any responsibility for any aspect of healthcare administered with the aid of information Multum provides. The information contained herein is not intended to cover all possible uses, directions, precautions, warnings, drug interactions, allergic reactions, or adverse effects. If you have questions about the drugs you are taking, check with your doctor, nurse or pharmacist.
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