Drug Interaction Report

Ibrutinib may increase the blood levels of gilteritinib in some patients. High levels of gilteritinib can 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 diseases, conduction abnormalities, or electrolyte disturbances (for example, magnesium or potassium loss due to severe or prolonged diarrhea or vomiting). The risk and/or severity of other side effects may also increase, including nausea, vomiting, decreased appetite, constipation, diarrhea, mouth sores, rash, muscle and joint pain, shortness of breath, cough, swelling of arms or legs, fever, infections, liver or kidney problems, inflammation of the pancreas, and low blood pressure. Talk to your doctor if you have any questions or concerns. Your doctor may be able to prescribe alternatives that do not interact, or you may need a dose adjustment or more frequent monitoring to safely use both medications. You should seek immediate medical attention if you develop sudden dizziness, lightheadedness, fainting, shortness of breath, or heart palpitations during treatment with gilteritinib. 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.

Ibrutinib should be taken once daily at approximately the same time everyday. Do not consume grapefruit, grapefruit juice, or Seville oranges unless directed otherwise by your doctor. Grapefruit and Seville oranges may significantly increase the blood levels of ibrutinib. This may increase the risk of side effects such as nausea, vomiting, diarrhea, abdominal pain, constipation, hemorrhage, kidney problems, and impaired bone marrow function resulting in low numbers of different types of blood cells. You may also be more likely to develop anemia, bleeding problems, or infections due to low blood cell counts. You should contact your doctor if you develop paleness, fatigue, dizziness, fainting, unusual bruising or bleeding, fever, chills, diarrhea, sore throat, muscle aches, shortness of breath, blood in phlegm, weight loss, red or inflamed skin, body sores, and pain or burning during urination. Also seek immediate medical attention if you experience signs and symptoms that may suggest kidney damage such as nausea, vomiting, loss of appetite, increased or decreased urination, sudden weight gain or weight loss, fluid retention, swelling, shortness of breath, muscle cramps, tiredness, weakness, dizziness, confusion, and irregular heart rhythm. 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.