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 a 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 in postmenopausal women, which may slow the growth of certain types of breast tumors that need estrogen to grow in the body.
Ribociclib is a cancer medicine that interferes with the growth and spread of cancer cells in the body.
Letrozole and ribociclib are used together in combination to treat a certain type of breast cancer that has spread to other parts of the body. This medicine is used in postmenopausal women.
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).
To make sure letrozole and ribociclib is safe for you, tell your doctor if you have ever had:
- heart disease, heart failure;
- a heart attack;
- heart rhythm problems, including slow heartbeats;
- long QT syndrome;
- an electrolyte imbalance (such as low levels of potassium or magnesium in your blood); or
- liver disease.
Tell your doctor if you have any signs of infection, such as fever or chills.
Your doctor will perform blood tests to make sure you do not have conditions that would prevent you from safely using letrozole and ribociclib. Your heart function may need to be checked using an electrocardiograph or ECG (sometimes called an EKG).
Do not use letrozole and ribociclib if you are pregnant. It could harm the unborn baby or cause birth defects. Use effective birth control to prevent pregnancy while you are using this medicine and for at least 3 weeks after your last dose.
You may need to have a negative pregnancy test before starting this treatment.
Letrozole and ribociclib may affect fertility (your ability to have children), whether you are a man or a woman. Talk with your doctor if you have concerns about this risk.
It is not known whether letrozole and ribociclib passes into breast milk or if it could harm a nursing baby. 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. Do not use this medicine in larger or smaller amounts or for longer than recommended.
It is best to take this medicine in the morning. 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.
When you start taking this medicine, you may need to take 3 ribociclib tablets per day during the first 21 days of each treatment cycle. Your doctor may gradually reduce your 21-day dose of ribociclib to only 2 tablets or 1 tablet per day, but you will continue to take 1 letrozole tablet every day for the full 28 days.
Follow your doctor's dosing instructions very carefully.
Swallow each tablet whole. Do not crush, chew, or break a tablet. Do not take any tablet that is broken or cracked.
If you vomit shortly after taking letrozole and ribociclib, 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.
Store each medicine in its original container at room temperature, away from moisture and heat.
What happens if I miss a dose?
Take the missed dose as soon as you remember. Skip the missed dose if it is almost time for your next scheduled dose. Do not take extra medicine to make up the missed dose.
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 and pomegranate may interact with letrozole and ribociclib and lead to unwanted side effects. Avoid the use of grapefruit or pomegranate products (fruit or juice) while taking letrozole and ribociclib.
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:
- a headache with chest pain and severe dizziness, fainting, fast or pounding heartbeats;
-
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, chills, swollen gums, painful mouth sores, pain when swallowing, skin sores, cold or flu symptoms, cough, trouble breathing.
Common side effects may include:
- nausea, vomiting, diarrhea, constipation;
- headache;
- feeling tired;
- 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.
Many drugs can interact with letrozole and ribociclib. This includes prescription and over-the-counter medicines, vitamins, and herbal products. Not all possible interactions are listed in this medication guide. 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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