Administration o gentamicin to obese patients.

The relation beteen a single bolus dose of gentamicin and the subsequent concentration in serum was studied in 17 obese patients with 82.7% excess weight and in 10 normal-weight patients. The apparent volume of distribution (AVD) for gentamicin in the two groups was calculated. In the obese group the AVD (17.7%) was found to be significantly lower than in the normal-weight group (23.2%). The AVD for the adipose tissue and the lean body mass was calculated to be 10.3% and 31.0%, respectively. The uptake of gentamicin in adipose tissue was found to be 43.7% of the uptake in the total body mass of normal-weight patients. A formula which indicates an adjudged body weight is recommended when the proper dose of gentamicin for obese patients is calculated. The formula is recommended only in cases of severe obesity.