Pharmacokinetics of ampicillin in anephric children without and during hemodialysis and in normal subjects
Lares-Asseff, I.; Jiménez, M.A.; Guzmán, A.; Zaltman, S.; Cravioto, J.
Boletin Medico del Hospital Infantil de Mexico 44(11): 677-684
1987
ISSN/ISBN: 0539-6115 PMID: 3689559 Document Number: 292297
Ampicillin pharmacokinetics was studied in five anephric children during periods on and off hemodialysis and in six normal young adults. From a dosage calculated at 50 mg/kg body weight patients and normal subjects received intravenously one-third of the dosage. Blood samples were collected previously and at 5, 15, 30, 60 minutes and 2, 4, 6 and 72 hours after the injection of the drug. Samples were assayed for ampicillin by Jusko's fluorometric method. Plasma concentrations declined with time in a bi-exponential manner. Ampicillin elimination was significantly lower when the child was off hemodialysis; the median value of half-life was 12.3 hours (range 5.2-36.6h). During hemodialysis median value was 3.8 h (range 2.9-12.0 h). Normal subjects had a median value of 1.77 h (range 1.15-2.08 h). Distribution volumes were higher off hemodialysis. Kinetic differences suggest the need to reduce the ampicillin dosage to one-tenth of the current dosage in patients off hemodialysis and to one-third when the patient is on hemodialysis.