Tobramycin pharmacokinetics in morbidly obese patients

Tobramycin kinetics were examined in 9 morbidly obese women following a single intravenous (120 mg) bolus. After the injection, serum elimination conformed to a 2-compartment open model with alpha and beta t1/2s of 0.285 and 2.1 hr. The volume of distribution (Varea) was determined to be 0.44 1/kg ideal body weight (IBW) and 0.20 1/kg total body weight (TBW). To normalize Varea to 0.26 1/kg, 58% of the patients' adipose weight (TBW -- IBW) must also be taken into account.