Drug Interaction Report

Although some in vitro data indicate synergism between macrolide antibiotics and penicillins, other in vitro data indicate antagonism. When these drugs are given together, neither has predictable therapeutic efficacy. Data are available for erythromycin, although theoretically this interaction could occur with any macrolide. Except for monitoring of the effectiveness of antibiotic therapy, no special precautions appear to be necessary.

It is not known to what extent eluxadoline may be metabolized by CYP450 isoenzymes and may interact with inhibitors of CYP450 isoenzymes. Some authorities have indicated that CYP450 has minimal involvement in the metabolism of eluxadoline. This suggests that alterations in the metabolism of eluxadoline by these isoenzymes are unlikely to have a clinically meaningful effect on the overall systemic exposure of eluxadoline. However, as a precautionary measure, it may be advisable to monitor patients for adverse effects such as sedation, nausea, vomiting, constipation, abdominal pain, liver enzyme elevations, and pancreatitis.

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.

Grapefruit juice may delay the gastrointestinal absorption of clarithromycin but does not appear to affect the overall extent of absorption or inhibit the metabolism of clarithromycin. The mechanism of interaction is unknown but may be related to competition for intestinal CYP450 3A4 and/or absorptive sites. In an open-label, randomized, crossover study consisting of 12 healthy subjects, coadministration with grapefruit juice increased the time to reach peak plasma concentration (Tmax) of both clarithromycin and 14-hydroxyclarithromycin (the active metabolite) by 80% and 104%, respectively, compared to water. Other pharmacokinetic parameters were not significantly altered. This interaction is unlikely to be of clinical significance.