Drug Interaction Report

Consumer information for this interaction is not currently available.

MONITOR: Coadministration with vadadustat may increase the plasma concentrations of drugs that are substrates of the CYP450 3A4 and/or CYP450 2C8 isoenzymes. Vadadustat is an inhibitor of CYP450 3A4 and CYP450 2C8 in vitro. However, clinical data are not available.

MANAGEMENT: Some authorities recommend using caution when vadadustat is used concomitantly with drugs that are substrates of CYP450 3A4 and/or CYP450 2C8, particularly sensitive substrates or those with a narrow therapeutic range. Monitoring for signs and symptoms of increased exposure to the CYP450 3A4 and/or CYP450 2C8 substrate should be considered whenever vadadustat is added to or withdrawn from therapy. The prescribing information for concomitant medications may be consulted to assess the benefits versus risks of coadministration, as well as any dosage adjustments that may be required during coadministration and/or following the discontinuation of a CYP450 3A4 and/or CYP450 2C8 inhibitor.

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.

Consumer information for this interaction is not currently available.

MONITOR: Smoking and alcohol consumption during therapy with vadadustat may increase the risk of gastrointestinal erosions. Serious erosions, including gastrointestinal bleeding and the need for red blood cell transfusions, have been reported during vadadustat clinical trials. Patients with a history of gastrointestinal erosion, peptic ulcer disease, and current tobacco smokers and alcohol drinkers may be at higher risk of gastrointestinal injury.

MANAGEMENT: Caution is advised if vadadustat is prescribed to current tobacco smokers or alcohol drinkers. Patients should be advised to contact their physician if they develop potential signs and symptoms of gastrointestinal injury such as abdominal pain, hematemesis, trouble swallowing, chest or throat pain, and/or black, tarry stools.