[Pharmacokinetics of combined antibiotic therapy in the newborn infant].
In 66 newborn infants (AGA) suffering from septicemia concentration time courses of gentamicin, ampicillin and cefotaxim were determined to perform and an individual drug monitoring. Gentamicin was analysed from capillar blood samples using EMIT, Ampicillin and Cefotaxim by HPLC-technique. Volumes of distribution, apparent elimination half lives, maximum -, minimum and steady state concentrations were calculated using digital iteration programs. Based on a fixed dose regimen the kinetic parameters of gentamicin were extremely variable. To achieve a median steady state concentration of 3 micrograms/ml gentamicin in serum corrections from -17% to +110% of the foregoing dose were necessary. With 100 mg/kg ampicillin or cefotaxim per day sufficient concentrations in serum were reached. But in some patients a dosage of 5-7 mg/kg/d of gentamicin is too low, while others show concentrations near to the toxic levels. By a combination of gentamicin plus ampicillin pharmacokinetic parameters are not influenced; while if gentamicin is combined with cefotaxim the apparent elimination halflife of gentamicin (beta-slope) is significantly reduced. Therefore an individual drug monitoring of drugs with a small therapeutic range, for example gentamicin, is necessary to optimize therapeutic results.
D000667:Ampicillin / Q000097:blood / Q000378:metabolism*; D002439:Cefotaxime / Q000097:blood / Q000378:metabolism*; D004347:Drug Interactions; D005839:Gentamicins / Q000097:blood / Q000378:metabolism*; D006207:Half-Life; D006801:Humans; D007231:Infant, Newborn; D007232:Infant, Newborn, Diseases / Q000188:drug therapy*; D007700:Kinetics
D005839:Gentamicins; D000667:Ampicillin; D002439:Cefotaxime
Pharmakokinetik der kombinierten Antibiotikatherapie beim Neugeborenen.