Treatment with gentamicin monitored by serum antibiotic assay

Gentamicin is very widely accepted as the most effective antibiotic for treatment of a number of serious Gram-negative infections, but one disadvantage associated with its use is the risk of toxicity particularly affecting the eighth nerve. An account is given of eight years' experience with this antibiotic in which obvious ototoxicity was avoided in hospitalized patients in whom gentamicin treatment was monitored by assay of the residual amounts of antibiotic present in the serum. The relationship between accumulation of gentamicin in patients with renal impairment and ototoxicity is discussed. Attention is drawn also to the presence of an increased risk of ototoxicity in patients, particularly the elderly, in whom mild-to-moderate degrees of renal impairment may be overlooked. In such patients modification of the frequency of the dose of gentamicin is necessary and a schedule of treatment based on the results of assay of residual serum levels of gentamicin is given.