Mass Balance and Drug Interaction Potential of IV Eravacycline Administered to Healthy Subjects.

Eravacycline is a novel, fully synthetic fluorocycline that is approved for the treatment of complicated intra-abdominal infections (cIAI) in adult patients. We report results from three studies in healthy subjects that investigated the distribution, metabolism, and excretion of intravenous (i.v.) eravacycline and the effect of a CYP3A4 inhibitor (itraconazole) and inducer (rifampin) on the pharmacokinetics (PK) of i.v. eravacycline. In the mass balance study, the majority of total radioactivity from [C-14] eravacycline was recovered in the feces, suggesting biliary/fecal elimination is the major route of excretion for eravacycline and its metabolites after IV administration. The volume of distribution (217 liters) was greater than that of extracellular fluid, which suggests distribution beyond the central compartment. In the drug-drug interaction studies, mean area under the concentration-time curve from 0 h to the last time point (AUC(0-t)) and half-life were increased approximately 30% to 40% after a concomitant dose of i.v. eravacycline and itraconazole and clearance (CL) was decreased. A reduction in total eravacycline exposure (AUC) of approximately 25% to 35% and an increase in CL of approximately 50% occurred with concomitant eravacycline and rifampin treatment. The dose of eravacycline should be increased to 1.5 mg/kg of body weight every 12 h when coadministered with a strong CYP3A inducer.