PHARMACOKINETIC CHARACTERISTICS OF PIPERACILLIN TAZOBACTAM

Piperacillin/tazobactam is a new combination of a broad-spectrum penic illin and a beta-lactamase inhibitor. In studies in healthy volunteers , the pharmacokinetics of piperacillin combined with tazobactam were s imilar to those of piperacillin alone. In contrast, tazobactam adminis tered with piperacillin achieved higher plasma concentrations and had a longer half-life than tazobactam administered alone. Intravenous inf usion of 4.0 g piperacillin with 0.5 g tazobactam over 5 min resulted in mean maximum plasma concentrations of 380 mug piperacillin/ml and 3 5.3 mug tazobactam/ml; half-lives were 1.14 h for piperacillin and 0.9 2 h for tazobactam. Within 30 min of infusion, piperacillin/tazobactam achieves 16 - 85 % of plasma concentrations in skin, muscle, lung, ga llbladder, and intestinal mucosa. Plasma and tissue levels remain abov e the MIC90s of major pathogens for 2 h post administration. These fin dings show that piperacillin/tazobactam is a truly synergistic combina tion which can be expected to be effective in treating a wide variety of infections in the clinical setting.