Clinical pharmacokinetics of continuous intravenous administration of penicillins

Theoretically, continuous intravenous administration of beta-lactam antibiotics has advantages over intermittent administration because of the close relationship between efficacy and the time the plasma concentration remains above the minimal inhibitory concentration that has been found in vitro. The aim of the present study was to establish the pharmacokinetic parameters of benzylpenicillin and cloxacillin administration in patients receiving high-dose benzylpenicillin or cloxacillin therapy by continuous infusion. A major part of the interindividual variation in the plasma concentrations at steady-state was attributable to variation in renal function, as estimated by the creatinine clearance. On the basis of these results, a nomogram was constructed that can be used to determine on an individualized basis the total daily dose of benzylpenicillin or cloxacillin necessary for each patient to obtain therapeutic plasma concentrations.