The bactericidal activity of antibiotics depends on the class of antibiotic used. Some antibiotics like vancomycin, aminoglycosides and fluoroquinolones are dose-dependent for their bactericidal activity. Other antibiotics like beta-lactam antibiotics are time-dependent antibiotics which depend on maintaining drug concentrations above the minimum inhibitory concentration of the targeted organisms. Therefore, it makes sense that a continuous infusion or prolonged infusion of beta-lactam antibiotics could increase bactericidal activity of beta-lactams vs intermittent dosing.
In this meta-analysis, 632 patients from three randomized trials were studied to compare a continuous-infusion of β-lactams compared with intermittent dosing strategy in critically ill patients with sepsis or septic shock. Continuous-infusion dosing significantly lowered 30-day mortality (relative risk, 0.73; number needed to treat [NNT], 15). For piperacillin-tazobactam (Zosyn) specifically, continuous infusion compared with intermittent dosing significantly lowered mortality (RR, 0.63; NNT, 11).
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