[Serum concentration of gentamicin in newborn infants].

Serum levels of gentamicin were determined in 15 premature infants (birth weight 1,120-2,250 g, gestational age 27-36 weeks) by agar immunoassay. The intramuscular applied doses was 6 mg/kg/day, the doses interval 12 hours. We found an increase of the gentamicin serum level during the first 72 hours after the beginning of therapy. At the second day of treatment the serum levels in 46.5% of all patients were determined below the therapeutic concentration, but a toxic level was found in more than 60% of all cases during the period of steady state. The serum levels were higher in preterm newborns of less than 1,500 g birth weight, then in more mature infants. We recommend: 1. To double the first doses of gentamicin 2. To modify the gentamicin level by expanded intervals of therapy and/or reduced doses under monitoring, especially during the first week of life.