Drug Interactions between disopyramide and eluxadoline

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.

MONITOR: Grapefruit juice may increase the plasma concentrations of orally administered drugs that are substrates of the CYP450 3A4 isoenzyme. The proposed mechanism is inhibition of CYP450 3A4-mediated first-pass metabolism in the gut wall by certain compounds present in grapefruit. Because grapefruit juice inhibits primarily intestinal rather than hepatic CYP450 3A4, the magnitude of interaction is greatest for those drugs that undergo significant presystemic metabolism by CYP450 3A4 (i.e., drugs with low oral bioavailability). In general, the effect of grapefruit juice is concentration-, dose- and preparation-dependent, and can vary widely among brands. Certain preparations of grapefruit juice (e.g., high dose, double strength) have sometimes demonstrated potent inhibition of CYP450 3A4, while other preparations (e.g., low dose, single strength) have typically demonstrated moderate inhibition. Pharmacokinetic interactions involving grapefruit juice are also subject to a high degree of interpatient variability, thus the extent to which a given patient may be affected is difficult to predict.

MANAGEMENT: Patients who regularly consume grapefruit or grapefruit juice should be monitored for adverse effects and altered plasma concentrations of drugs that undergo significant presystemic metabolism by CYP450 3A4. Grapefruit and grapefruit juice should be avoided if an interaction is suspected. Orange juice is not expected to interact with these drugs.

Ethanol significantly increases the renal elimination of disopyramide, apparently by inducing diuresis (inhibition of antidiuretic hormone). Limited data show that ethanol does not, however, significantly affect the elimination half-life or total plasma clearance of disopyramide. No special precautions appear to be necessary.