[Gentamicin administration in newborns: once daily]. / Gentamicinedosering bij pasgeborenen: eenmaal daags.

OBJECTIVE: To determine the serum levels of gentamicin in newborn on one or two daily doses. DESIGN: Retrospective and subsequently prospective, descriptive. SETTING: Department of Pediatrics of the Deventer Hospital, the Netherlands. METHOD: Gentamicin trough and peak plasma levels were analysed retrospectively in 30 neonates to whom gentamicin 3-4 mg/kg/day in two doses had been administered in 1995. In a subsequent prospective study in 1996, 52 neonates received gentamicin 4 mg/kg/day in one dose. Optimal levels were defined as a trough of < 2 mg/l and a peak of 6-12 mg/l. Levels were determined using a immunoassay. RESULTS: Both groups were similar in gestational age, weight and age at the start of treatment. Both trough and peak plasma levels were not known in all patients. Adequate gentamicin trough levels were seen more often in the 'once daily' group than in the 'twice daily' group, in both the premature (12/14 = 86% versus 3/7 = 43%; p = 0.04) and non-premature (36/37 = 97% versus 18/23 = 78%; p = 0.017) neonates. Peak levels were higher in the 'once daily' group than in the 'twice daily' group, in both the prematures (11/13 = 85% versus 1/7 = 14%; p = 0.002) and non-prematures (25/28 = 89% versus 2/22 = 9%; p < 0.000001). Optimal trough and peak levels were found in 9/13 (69%) of the premature and 24/27 (89%) of the non-premature neonates treated according to the 'once daily' schedule, compared with 0 and 1/22 (5%) respectively in the neonates treated according to the 'twice daily' regimen (p = 0.003 and p < 0.0001, respectively). CONCLUSION: In view of the reported levels and the literature, an initial dose of gentamicin of 4.0 mg/kg/day once a day is advised for neonates.

Ciprofloxacin does not impair the elimination of diazepam in humans.

The pharmacokinetics of a single iv dose of 10 mg diazepam and the renal excretion of its metabolites resulting from N-demethylation and C-3-hydroxylation were investigated in 10 healthy volunteers when diazepam was administered alone and on day 3 of administration of the fluoroquinolone ciprofloxacin (500 mg twice per day). No significant changes in the diazepam half-life, its volume of distribution, the total body clearance, or the renal clearance were observed. In addition, the renal excretion of the metabolites desmethyldiazepam, 3-hydroxydiazepam (temazepam), and 3-hydroxydesmethyldiazepam (oxazepam) were not altered by ciprofloxacin co-medication. These data demonstrate that in a 500 mg twice per day oral dosage, ciprofloxacin does not influence the metabolic clearance of diazepam in young healthy volunteers.