Drug Interaction Report

Apalutamide may significantly reduce the blood levels of avapritinib, which may make the medication less effective in treating your cancer. 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.

Avapritinib should be taken on an empty stomach, one hour before or two hours after a meal. Do not consume grapefruit, grapefruit juice, or any supplements that contain grapefruit extract during treatment with avapritinib unless directed otherwise by your doctor. Grapefruit juice can increase the blood levels of avapritinib. This may increase the risk and/or severity of serious side effects such as bleeding in the brain; cognitive impairment (forgetfulness, confusion, trouble thinking); changes in mood or behavior; hallucinations; fluid retention or swelling; and decreases in blood cell counts. You may also be more likely to develop anemia, bleeding problems, or infections due to low blood cell counts. 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.