Drug Interactions between eluxadoline and Tykerb

CONTRAINDICATED: Consumption of more than 3 alcoholic beverages per day may increase the risk of acute pancreatitis during treatment with eluxadoline. Pancreatitis has been reported rarely during clinical trials of eluxadoline, and may or may not be related to sphincter of Oddi spasm.

ADJUST DOSING INTERVAL: High-fat meals may reduce the oral bioavailability of eluxadoline. In 28 healthy volunteers, administration of a single 100 mg dose of eluxadoline with a high-fat meal (approximately 800 to 1000 total calories, 50% from fat) decreased eluxadoline peak plasma concentration (Cmax) and systemic exposure (AUC) by 50% and 60%, respectively, compared to administration in the fasted state. There was no significant effect on the time to peak concentration (Tmax). The clinical relevance of this interaction is unknown. It should be noted that phase 3 clinical trials were conducted under fed conditions.

MANAGEMENT: Chronic or acute excessive use of alcohol should be avoided during treatment with eluxadoline. Alcoholism, alcohol abuse, alcohol addiction, and consumption of more than 3 alcoholic beverages per day are considered contraindications to the use of eluxadoline. The product labeling recommends taking eluxadoline with food. Patients should be advised to stop taking eluxadoline and seek medical attention if they experience potential symptoms of pancreatitis such as persistent nausea, vomiting, abdominal tenderness, and upper abdominal pain, especially that which is made worse after eating or radiates to the back or shoulders.

GENERALLY AVOID: Grapefruit juice may increase the plasma concentrations of lapatinib. The proposed mechanism is inhibition of CYP450 3A4-mediated first-pass metabolism in the gut wall by certain compounds present in grapefruits.

ADJUST DOSING INTERVAL: Food can significantly increase the oral bioavailability of lapatinib. According to the manufacturer, lapatinib peak plasma concentration (Cmax) was approximately 2.5- and 3-fold higher and systemic exposure (AUC) 3- and 4-fold higher when administered with a low fat meal (5% fat; 500 calories) or with a high-fat meal (50% fat; 1000 calories), respectively, compared to fasting. Dividing the daily dose also resulted in an approximately 2-fold higher systemic exposure at steady state compared to the same total dose administered once daily.

MANAGEMENT: Patients treated with lapatinib should preferably avoid the consumption of grapefruit or grapefruit juice. The manufacturer recommends that lapatinib be administered at least one hour before or one hour after a meal. The lapatinib dose is administered once daily and should not be divided.