Variation in the pharmacokinetics of gentamicin and tobramycin in patients with pleural effusions and hypoalbuminemia.

The pharmacokinetic parameters of gentamicin and tobramycin were evaluated and compared for 260 patients with pleural effusions and 1,049 patients without pleural effusions by chest radiograph. Pharmacokinetic data were collected prospectively and analyzed by using our aminoglycoside data base. Univariate analysis revealed that the patients with pleural effusions demonstrated significantly lower serum albumin concentrations, greater aminoglycoside volumes of distribution, longer elimination half-lives, and lower peak and higher trough concentrations in serum than the patients without pleural effusions. Patients with pleural effusions were significantly older and had lower total body weight. Stepwise multiple linear regression analysis revealed that lower total body weight and serum albumin concentration, presence of pleural effusion, and greater age were associated with significantly greater volumes of distribution. Calculated creatinine clearance, age, total body weight, and shock were associated with reduced aminoglycoside clearance in these patients.