Comparative Pharmacokinetics, Pharmacodynamics, and Tolerability of Ertapenem 1 Gram/Day Administered as a Rapid 5‐Minute Infusion versus the Standard 30‐Minute Infusion in Healthy Adult Volunteers

Abstract

To compare ertapenem pharmacokinetics, pharmacodynamics, and tolerability when administered as a rapid 5-minute infusion to the standard 30-minute infusion. Prospective, randomized, crossover pharmacokinetic study. Clinical research center. Twelve healthy adult volunteers. Each subject received ertapenem 1g intravenously, administered either as a rapid 5-minute infusion or the standard 30-minute infusion, every 24hours for 3days (first phase); after a 4-day washout period, each subject then received the other infusion every 24hours for 3days (second phase). Plasma samples were collected after the first and third (steady-state) doses of each study phase, and protein binding was assessed by use of ultrafiltration. Pharmacokinetic analyses were conducted using noncompartmental and compartmental methods. A 5000-subject Monte Carlo simulation was used to assess the probability of target attainment for free drug concentration remaining above the minimum inhibitory concentration (MIC) for 40% or greater of the dosing interval (40% fT>MIC) over an MIC range. Ertapenem was well tolerated and adverse events were similar for both infusions. The ertapenem steady-state mean±SD maximum concentrations were 193.3±43.3 and 165.7±20.4mg/L for the 5- and 30-minute infusions, respectively; the mean±SD areas under the concentration-time curves from 0-24hours were 561.2±77.0 and 531.3±56.9μg · hr/ml (geometric mean ratio 1.008, 90% confidence interval 0.999-1.017), respectively. Protein binding was concentration dependent (range 87.9-98.9%). A two-compartment model best described ertapenem pharmacokinetics with the following parameter estimates: clearance 1.89±0.19L/hr, volume of central compartment 5.04±0.56L, and transfer constants k12 0.43±0.08/hr and k21 0.44±0.07/hr. The probabilities of target attainment for 5- and 30-minute infusions were 97.0% and 97.9% at an MIC of 0.25 mg/L and 1.7% and 2.8% at an MIC of 0.5mg/L, respectively. Ertapenem administered as a rapid 5-minute infusion provides a well tolerated, bioequivalent, and pharmacodynamically equivalent regimen to the 30-minute infusion at clinically relevant MICs.