Drug Interactions between efavirenz and ibrutinib

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.

Taking efavirenz with food increases the amount of medicine in your body, which may increase the frequency of side effects. You should take efavirenz once a day on an empty stomach, preferably at bedtime. Taking it at bedtime may make some side effects such as dizziness, trouble sleeping, drowsiness, trouble concentrating, and/or unusual dreams less bothersome. However, these symptoms may be more severe if efavirenz is used with alcohol or mood-altering (street) drugs. You should avoid driving or operating hazardous machinery until you know how the medication affects you. 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.