Drug Interaction Report

Selpercatinib may increase the blood levels and effects of resmetirom. This may increase the risk and or severity of side effects such as liver and/or gallbladder problems, diarrhea, nausea, itching, vomiting, constipation, abdominal pain and dizziness. Seek immediate medical attention if you develop signs and symptoms of liver damage such as fever, chills, unusual bleeding or bruising, skin rash, fatigue, nausea, vomiting, dark colored urine, light colored stools, yellowing of the skin or eyes and pain or tenderness in the upper middle or upper right area of your stomach. 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. Talk to your doctor if you have any questions or are experiencing particularly bothersome side effects. 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.

You should limit or avoid consumption of grapefruit and grapefruit juice during treatment with selpercatinib unless directed otherwise by your doctor. Grapefruit juice may increase the blood levels of selpercatinib. High levels of selpercatinib can increase the risk of an irregular heart rhythm that may be serious and potentially life-threatening, although it is a relatively rare side effect. You may be more susceptible if you have a heart condition called congenital long QT syndrome, other cardiac diseases, conduction abnormalities, or electrolyte disturbances (for example, magnesium or potassium loss due to severe or prolonged diarrhea or vomiting). The risk and/or severity of other side effects may also increase, including nausea, vomiting, constipation, diarrhea, rash, muscle and joint pain, swelling of arms or legs, liver problems, high blood pressure, and bleeding complications. Talk to your doctor if you experience intolerable or troublesome side effects, or you have other questions or concerns. You should seek immediate medical attention if you develop sudden dizziness, lightheadedness, fainting, shortness of breath, or heart palpitations during treatment with selpercatinib. 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.