Study Objective. To compare continuous versus intermittent administration of piperacillin-tazobactam with regard to clinical, microbiologic, and economic outcomes.

Design. Prospective, open-label controlled study.

Setting. Community teaching hospital.

Patients. Ninety-eight hospitalized patients prescribed piperacillintazobactam.

Intervention. Substitutions were implemented so that 47 patients initially prescribed intermittent infusion of piperacillin-tazobactam were switched to continuous infusion of this drug combination. Dosages varied in accordance with the type of infection and each patient's renal function. Fifty-one other patients with similar demographics and types of infection received intermittent infusion with piperacillin-tazobactam.

Measurements and Main Results. Clinical success rates were 94% for the continuous-infusion group and 82% for the intermittent-infusion group (p=0.081). Microbiologic success rates were 89% for the continuous-infusion group and 73% for the intermittent-infusion group (p=0.092). Days to normalization of fever were significantly lower (p=0.012) in the continuous-infusion group (1.2 ± 0.8 days) than in the intermittent-infusion group (2.4 ± 1.5 days). Level 1 and level 2 costs/patient were both reduced by continuous infusion, although the difference was statistically significant only for level 2 costs ($399.38 ± 407.22 for continuous infusion vs $523.49 ± 526.85 for intermittent infusion, p=0.028).

Conclusion. Continuous infusion of piperacillin-tazobactam provided clinical and microbiologic outcomes equivalent to those for intermittent infusion. Compared with intermittent infusion, continuous infusion significantly shortened the time to temperature normalization, while also offering a significant reduction in level 2 expenditures.