RESUMEN
Amoxicillin is commonly used for the treatment of neonatal bacterial infection with intermittent dosing (ID) regimens. However, increasing bacterial resistance, in addition to a lack of new antimicrobial agents, urges the optimization of current therapeutic options. Clinical studies in adults suggest continuous infusion (CI) regimens of beta-lactam antibiotics to be superior to ID. There are as yet no guidelines concerning the CI dosing of amoxicillin. The present study was developed to describe the CI pharmacokinetics and -dynamics of amoxicillin during the first 3 days of life in search of the optimal dosing regimen. Neonates with a gestational age above 34 weeks, at risk of neonatal infection and requiring amoxicillin therapy, were included. Serum concentrations of amoxicillin were measured during CI on days 1 and 3 in the steady state. Twenty-two serum samples of 11 patients were collected. All patients reached and retained serum concentrations of amoxicillin within the therapeutic range without exceeding the toxic concentration (serum concentrations on day 1 mean 55.4 mg/l, range 30.9-69.5, SD 10.5, and on day 3 48.8 mg/l, range 25.5-92.4, SD 18.4). There was no significant decrease in concentration from day 1 to day 3 (p = 0.38). This study showed therapeutic, nontoxic concentrations of amoxicillin in neonates on CI of amoxicillin in the first 3 days of life. Randomized controlled trials should reveal whether the clinical benefits of the CI of amoxicillin exceed those of ID regimens.