RT Journal Article
SR Electronic
T1 Gentamicin: use of a programmable calculator to determine dosages from pharmacokinetic data for individual patients
JF Canadian Medical Association Journal
JO CMAJ
FD Canadian Medical Association
SP 1459
OP 1463
VO 124
IS 11
A1 de Repentigny, L.
A1 Dumont, L.
A1 Le Lorier, J.
A1 Morisset, R.
A1 Larochelle, P.
A1 Courchesne, Y.
YR 1981
UL http://www.cmaj.ca/content/124/11/1459.abstract
AB Gentamicin, an antibiotic frequently used in the treatment of gram-negative infections, has a narrow therapeutic index, so the correct prediction of its serum concentrations is important. Recent studies have emphasized the dubious accuracy of commonly used formulas, and computer programs that provide pharmacokinetic data for individual patients from multiple blood samples have helped to adjust dosages but are expensive. This study tested the applicability of a method using only two blood samples and a programmable calculator to estimate pharmacokinetic parameters for individual patients and adjust dosages to aim at peak and trough serum levels of 6 and 1 micrograms/ml respectively. In the 48 patients with normal renal function this method produced peak serum concentrations of gentamicin within 1 microgram/ml of the desired level in 22 (46%) and therapeutic peak concentrations (between 4 and 10 micrograms/ml) in all the patients. In 10 patients with renal failure it produced peak serum concentrations within 1 microgram/ml of the desired value in 4 and therapeutic serum concentrations in 7. Two patients had peak concentrations below 4 micrograms/ml and one had a peak concentration above 10 micrograms/ml. Two of the three patients whose serum levels were outside the therapeutic range had unstable renal insufficiency. Thus, patients with renal insufficiency need continued monitoring of the serum level of gentamicin, particularly when their renal function is changing.