Serum and Blister Fluid Pharmacokinetics of Amikacin in Severe Burn Patients

Objective: To characterize amikacin pharmacokinetics in serum and in blister fluid of severe burn patients to guide optimal treatment timing. Methods: Patients (N = 32) were divided into four groups based on amikacin administration timing and groups received drug minutes to hours after injury. In Groups A, B, C, and D, amikacin (400 mg, IV) was administered 3 - 4, 10, 20 and 30 h post burn injury, respectively (N = 8 for all groups). Next blister fluid and venous blood samples from 9 patients were obtained at 0, 0.25, 0.5, 1, 2, 3, 4, 5, 6, and 7 h after drug infusion. Amikacin concentrations were measured with a fluorescent polarization immunoassay and pharmacokinetics was deduced using DAS3.2.5. Statistical analyses performed with SPSS13.0. Results: Compared with normal values, t1/2z of amikacin from burn patients was shortened in serum but amikacin half-lives in blister fluid was significantly greater than serum half-life values (p < 0.05). Groups A and B had greater pharmacokinetic values at each time point, and Group D did not achieve antibacterial concentrations of amikacin. Conclusion: Early amikacin administration in severe burn patients offers greater concentrations of drug in serum and blister fluids.