To the Editor.
—Wingfield et al, in the January Archives (1983;101:117-120), reported on aqueous humor concentrations of amikacin following 7.5-mg/kg doses injected intramuscularly in man. While we found their data to be of interest, we disagree with several of their statements. First, although amikacin is available for intramuscular use, it is also available for intravenous (IV) use and is usually given by this latter route for serious infections. Second, the mean concentration of amikacin in the aqueous humor of 1 mg/L could be expected to inhibit only 26% of Escherichia coli, 18% of Proteus mirabilis, 32% to 73% of indole-positive Proteus sp, 13% of Serratia marcescens, 10% of Klebsiella pneumoniae, and 10% of Pseudomonas aeruginosa.1-3 While it is true that the 1-mg/L level "is above the MIC [minimal inhibitory concentration] for many strains of gram-negative bacteria," the low percentages of organisms that are actually sensitive to this aqueous-humor concentration
Axelrod JL, Kochman RS. Aqueous-Humor Concentrations of Amikacin. Arch Ophthalmol. 1983;101(7):1145. doi:10.1001/archopht.1983.01040020147029