Fosfomycin kinetics after intravenous and oral administration to human volunteers

Abstract

The pharmacokinetics of fosfomycin, administered intravenously and orally at two different doses (20 and 40 mg/kg of body weight), was studied in seven volunteers. The elimination profile of this antibiotic, when administered intravenously, followed a two-compartment kinetic model, independent of dosage, giving an elimination half-life of 2.23 ± 0.62 h and an average total volume of distribution at steady state of 0.34 liter/kg. Peak serum levels after rapid intravenous administration of 20 and 40 mg/kg were 132.1 ± 31.8 and 259.3 ± 32.5 μg/ml, respectively. Peak serum levels after oral administration were 7.1 ± 1.6 and 9.4 ± 3.6 μg/ml for the 20 and 40 mg/kg doses, respectively. During the first 24 h after administration, an average of 80% of the intravenous doses and less than 25% of the oral doses were recovered in the urine.