Influence of total parenteral nutrition on amikacin pharmacokinetics

Six patients under total parenteral nutrition (TPN) and eight control patients received 200 mg of amikacin by iv infusion in 0.5 h. Amikacin concentrations of serum and urine were determined by fluorescence polarization immunoassay. At 6 h after the beginning of administration, the amikacin level in serum of TPN group (2.3 +/- 0.8 micrograms/ml) was significantly higher than control (1.3 +/- 0.8 microgram/ml). There was no significant difference between the 24-h urine output of 2 groups. Pharmacokinetic calculations were based on a two-compartment open-system model. The T1/2 beta and apparent volumes of distribution (Vc, Vdss, V2) of TPN group were significantly greater than those of control group. The body clearance of amikacin in TPN group was slower than control. It is suggested that serum amikacin concentrations should be monitored in clinical TPN patients to prevent toxic reactions.