Drug Interaction Report

Using bosentan together with fostamatinib may alter the blood levels of both medications. Specifically, the blood levels of fostamatinib may decrease, which may reduce its effectiveness in treating your condition. At the same time, fostamatinib may cause the blood levels of bosentan to increase. You may be more likely to experience side effects of bosentan such as nausea, vomiting, fatigue, headache, low blood pressure, fluid retention, anemia, 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, or you may need a dose adjustment or more frequent monitoring by your doctor to safely use both medications. Contact your doctor if you develop fainting; sudden, unexplained weight gain; swelling of the legs or ankles; chest pain; or difficulty breathing during treatment with these medications. You should also seek medical attention if you experience potential signs and symptoms of liver damage such as fever, rash, loss of appetite, nausea, vomiting, fatigue, upper abdominal pain, dark urine, or yellowing of the skin and eyes. 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.