Drug Interaction Report

Tazemetostat may increase the blood levels of treprostinil. Let your doctor know if you experience increased side effects of treprostinil such as dizziness, lightheadedness, fainting, flushing, diarrhea, unusual bleeding or bruising, and swelling of the arms or legs. You may need a dose adjustment or more frequent monitoring by your doctor to safely use both medications. 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.

Do not consume grapefruit or grapefruit juice during treatment with tazemetostat. Grapefruit juice can significantly increase the blood levels and effects of tazemetostat, which may increase the risk of serious side effects such as bleeding complications, pain, bone pain, tiredness, shortness of breath, excess fluid around the lungs, and development of new (second) cancers. 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.