Drug Interactions between panobinostat and rifampin

GENERALLY AVOID: Concurrent use of rifampin in patients who ingest alcohol daily may result in an increased incidence of hepatotoxicity. The increase in hepatotoxicity may be due to an additive risk as both alcohol and rifampin are individually associated with this adverse reaction. However, the exact mechanism has not been established.

ADJUST DOSING INTERVAL: Administration with food may reduce oral rifampin absorption, increasing the risk of therapeutic failure or resistance. In a randomized, four-period crossover phase I study of 14 healthy male and female volunteers, the pharmacokinetics of single dose rifampin 600 mg were evaluated under fasting conditions and with a high-fat meal. Researchers observed that administration of rifampin with a high-fat meal reduced rifampin peak plasma concentration (Cmax) by 36%, nearly doubled the time to reach peak plasma concentration (Tmax) but reduced overall exposure (AUC) by only 6%.

MANAGEMENT: The manufacturer of oral forms of rifampin recommends administration on an empty stomach, 30 minutes before or 2 hours after meals. Patients should be encouraged to avoid alcohol or strictly limit their intake. Patients who use alcohol and rifampin concurrently or have a history of alcohol use disorder may require additional monitoring of their liver function during treatment with rifampin.

GENERALLY AVOID: Grapefruit juice may increase the plasma concentrations of panobinostat. The proposed mechanism is inhibition of CYP450 3A4-mediated first-pass metabolism in the gut wall by certain compounds present in grapefruit. Increased exposure to panobinostat may increase the risk of adverse effects such as nausea, vomiting, diarrhea, anorexia, peripheral edema, cardiotoxicity, ECG abnormalities, electrolyte disturbances, bleeding complications, hepatotoxicity, and myelosuppression.

Food may delay the rate of absorption of panobinostat, but does not significantly affect the overall extent of absorption. When a single oral dose of panobinostat was administered to 36 patients with advanced cancer 30 minutes after a high-fat meal, panobinostat peak plasma concentration (Cmax) and systemic exposure (AUC) were approximately 44% and 16% lower, respectively, compared to administration under fasting conditions. The median time to maximum concentration (Tmax) was prolonged by 2.5 hours.

MANAGEMENT: Patients should avoid consumption of grapefruit or grapefruit juice during treatment with panobinostat. The manufacturer also recommends avoiding star fruit, Seville oranges, pomegranate, and pomegranate juice. Panobinostat may be administered with or without food.