Ceftolozane-Tazobactam Pharmacokinetics in a Critically Ill Patient on Continuous Venovenous Hemofiltration

Extended-infusion ceftolozane-tazobactam treatment at 1.5 g every 8 h was used to treat multidrug-resistant Pseudomonas aeruginosa in a critically ill patient on continuous venovenous hemofiltration. Serum drug concentrations were measured at 1, 4, 5, 6, and 8 h after the start of infusion. Prefilter levels of ceftolozane produced a maximum concentration of drug (C-max) of 38.57 mu g/ml, concentration at the end of the dosing interval (C-min) of 31.63 mu g/ml, time to C-max (T-max) of 4 h, area under the concentration-time curve from 0 to 8 h (AUC(0-8)) of 284.38 mu g.h/ml, and a half-life (t(1/2)) of 30.7 h. The concentrations were eight times the susceptibility breakpoint for the entire dosing interval.