Drug Interaction Report

Using ribociclib together with fosphenytoin is not recommended. Combining these medications may significantly reduce the blood levels of ribociclib, which may make the medication less effective in treating your cancer. Using fosphenytoin with ribociclib may also increase the risk of an irregular heart rhythm that may be serious and potentially life-threatening, although it is a relatively rare side effect. You should seek immediate medical attention if you experience sudden dizziness, lightheadedness, fainting, shortness of breath, or heart palpitations during treatment with these medications, whether together or alone. Talk to your doctor if you have any questions or concerns. Your doctor may be able to prescribe alternatives that do not interact. It is important to tell your doctor about all other medications you use, including vitamins and herbs. Do not stop using any medications without first talking to your doctor.

Patients should not consume pomegranates, pomegranate juice, grapefruit, or grapefruit juice during treatment with ribociclib unless directed otherwise by your doctor. Pomegranate juice or grapefruit juice can increase the blood levels of ribociclib. You may be more likely to experience side effects such as nausea; vomiting; diarrhea; loss of appetite; abdominal pain; mouth sores; hair loss; weakness; and impaired bone marrow function resulting in low numbers of different types of blood cells, which can increase the risk of anemia, bleeding problems, and infections. It is important to tell your doctor about all other medications you use, including vitamins and herbs. Do not stop using any medications without first talking to your doctor.