Drug Interactions between ivosidenib and pralsetinib

Do not consume grapefruit or grapefruit juice during treatment with ivosidenib unless directed otherwise by your doctor. Grapefruit juice can increase the blood levels of ivosidenib. This may increase the risk of an irregular heart rhythm that may be serious and potentially life-threatening. You may be more susceptible if you have a heart condition called congenital long QT syndrome, other cardiac diseases, conduction abnormalities, or electrolyte disturbances (for example, magnesium or potassium loss due to severe or prolonged diarrhea or vomiting). Talk to your doctor if you have any questions or concerns. You may take ivosidenib with or without food, but avoid taking it with a high-fat meal, as this can also increase blood levels of the medication. An example of a high-fat meal includes 2 eggs fried in butter, 2 strips of bacon, 2 slices of white bread with butter, 1 croissant with 1 slice of cheese, and 8 ounces of whole milk (approximately 1,000 calories and 58 grams of fat). You should seek immediate medical attention if you develop sudden dizziness, lightheadedness, fainting, shortness of breath, or heart palpitations during treatment. 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.

Food should not be consumed for at least 2 hours before and at least 1 hour after taking pralsetinib. Do not consume grapefruit, grapefruit juice, any supplements that contain grapefruit, Seville oranges, or Seville orange juice as these products can increase the blood levels of pralsetinib. This may increase the risk and/or severity of serious side effects such as lung problems, liver problems, high blood pressure, fatigue, muscle and joint pain, and bleeding complications. Some sources also warn that combining these medicines could 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 may be more susceptible if you have a heart condition called congenital long QT syndrome, other cardiac disease, conduction abnormalities, or electrolyte disturbance (for example, magnesium or potassium loss due to severe or prolonged diarrhea or vomiting). Talk to your doctor if you have any questions or concerns. 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.