To the Editor.
—In their review of treatment of endocarditis, Dr Wilson and colleagues1 recommend that aminoglycoside dosages in obese patients should be based on ideal body weight rather than actual weight. Adipose tissue does contribute to the overall volume of distribution of aminoglycosides, but only about 40% as much as does lean body tissue.2 Doses based on ideal body weight alone may result in serious underdosage in remarkably obese patients.3 If 40% of the weight of the excess adipose tissue (calculated by subtracting ideal from actual body weight) is added to ideal body weight, the resultant sum will provide a rational weight for the purposes of calculating an aminoglycoside dose.2
Schwartz SN. Antibiotic Treatment for Infective Endocarditis. JAMA. 1996;275(12):911. doi:10.1001/jama.1996.03530360021027