Drug Interaction Report

ADJUST DOSING INTERVAL: Antibiotics may interfere with the therapeutic effects of fecal microbiota, which contains live bacteria. The mechanism may be related to the antibiotic inactivating the bacteria or reducing bacterial replication. In clinical studies an antibiotic washout period between 24 to 72 hours was required prior to the rectal administration of fecal microbiota.

MANAGEMENT: Although data are limited, it may be prudent to have an antibiotic washout period between 24 to 72 hours prior to administration of the rectal formulation of fecal microbiota. In addition, the manufacturer recommends avoiding oral antibiotics for up to 8 weeks after administration of the rectal formulation of fecal microbiota.

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.