Drug Interaction Report

Consumer information for this interaction is not currently available.

GENERALLY AVOID: Coadministration with inhibitors of CYP450 2C9 may increase the plasma concentrations of lonafarnib. In vitro, lonafarnib has been shown to be primarily metabolized by CYP450 3A4 and, to a lesser extent, by CYP450 1A2, 2A6, 2C8, 2C9, 2C19, and 2E1. A drug-drug interaction study of lonafarnib with CYP450 2C9 inhibitors has not been conducted. Increased exposure to lonafarnib may increase the risk and/or severity of adverse effects such as nausea, vomiting, diarrhea, anorexia, electrolyte disturbances, liver enzyme elevations, myelosuppression, infection, and hypertension.

MANAGEMENT: The manufacturer recommends avoiding concomitant use of lonafarnib with CYP450 2C9 inhibitors. If coadministration is required, patients should be closely monitored for common adverse effects as well as arrhythmias and events such as syncope and heart palpitations, since the effect of increased exposures on the QT interval is unknown.

Lonafarnib should be taken with the morning and evening meals and an adequate amount of water. Do not consume grapefruit, grapefruit juice, or Seville oranges (also known as bitter or sour oranges).During treatment with lonafarnib. Juice from grapefruits and Seville oranges can increase the blood levels of lonafarnib. This may increase the risk and/or severity of side effects such as nausea, vomiting, diarrhea, loss of appetite, electrolyte (e.G., calcium, magnesium, potassium, phosphate, sodium) abnormalities, liver problems, low red and white blood cell counts, infection, and high blood pressure. 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.

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.