Drug Interactions between tazemetostat and Viekira XR

Ritonavir may significantly increase the blood levels of tazemetostat. This 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. 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. 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.

Tazemetostat may increase the blood levels of dasabuvir, one of the components of your hepatitis C medication. In some cases, this may increase the risk of side effects such as irregular heart rhythm and liver problems. Talk to your doctor if you have any questions or concerns. Your doctor may be able to prescribe alternatives that do not interact. You should seek immediate medical attention if you develop fever, chills, joint pain or swelling, unusual bleeding or bruising, skin rash, itching, loss of appetite, fatigue, nausea, vomiting, dark colored urine, light colored stools, and/or yellowing of the skin or eyes, as these may be signs and symptoms of liver damage. 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.