Distribution of Gentamicin in Body Fluids

ment, and a revision of dosage then becomes necessary.Modi- fication of dosage in renal failure is more practical for routine hospital use if only the interval between doses is altered as outlined in Table III.It is, however, feasible to use a smaller dose of 60 or 40 mg. at more frequent intervals after the initial loading dose of 80 mg. to maintain a therapeutic serum level.In only one instance have there been any observed toxic side- effects.These occurred in a woman (Case 9, Table I) who one hour after a single 80-mg.injection complained of marked giddiness.The symptoms were associated with a peak serum level of 12 ,ug./ml., the highest in the series, and persisted for one and a half hours.We have not administered gentamicin on a body-weight basis but have used the more simple and practical method of giving 80 mg.(2-ml.phial) at suitable intervals, depending on renal function.There is, however, a negative correlation between body weight and peak serum level in the patients studied which is statistically significant at the 5 % level.In view of the high peak level attained in the one subject described, who weighed only 46.5 kg., we now use a 60-mg.dose in patients weighing less than 60 kg.The present study is part of a clinical investigation of gentamicin in resistant urinary tract infections, including Ps. aeruginosa, which is still in progress.This study includes pre- treatment and post-treatment vestibulometry to assess toxicity, and to date there have been no recorded untoward sequelae of treatment with the increased dose regimen described. SummarySerum levels of gentamicin have been determined in normal subjects and in patients with renal impairment after 80 mg.intramuscularly.The average peak serum level obtained was 7.0 ttg./ml., which is independent of renal function, assessed