Chemotherapy
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The objective of this study was to assess the impact of intravenous infusion systems on the pharmacokinetic parameters of tobramycin in newborn infants. Thirty infants (gestational age 28-38 weeks; birth weight 0.8-3.5 kg; postnatal age 4-10 days) with presumed or proven gram-negative infection were studied. Tobramycin (2.5 mg/kg) was administered every 12 h over 0.5 h using two of four infusion systems at similar flow rates in a crossover fashion: syringe pump (auto syringe) versus either IVAC-y site, IVAC-flashball or IMED-y site. ⋯ The apparent distribution volume of tobramycin was 1.02 +/- 0.68 with IVAC-y and 0.65 +/- 0.22 l/kg with auto syringe (p less than 0.05). The elimination half-life was 10.4 +/- 6.9 h with IVAC-y and 6.6 +/- 2.3 h with auto syringe (p less than 0.05); other systems and parameters were not different. These data demonstrate that the type of infusion system can markedly influence the estimation of certain pharmacokinetic parameters of tobramycin in newborn infants.