Comparison of the pharmacokinetics of five aminoglycoside and aminocyclitol antibiotics using allometric analysis in mammal and bird species

The allometric equations relating the half-life, the volume of distribution and the total body clearance of gentamicin, amikacin, tobramycin, kanamycin and apramycin to body weight for mammalian and mammalian + avian species were defined. Literature data were used as a source of comparative pharmacokinetic data. For all antibiotics examined half-life intercepts ranged from 0.49 to 1.66, slopes from 0.05 to 0.45, volume of distribution intercepts--0.13-0.75, slope-- 0.77-1.41, total body clearance intercepts--0.88-8.8 and slope--0.62-1.04. A better relationship between pharmacokinetic parameters and body weight was shown when all values were included in the allometric analysis. Different values of intercept and slope between birds and mammals were found in gentamicin and apramycin studies. In some cases, slopes and intercepts changed when all values of pharmacokinetic parameters were included. We conclude that small difference exist between pharmacokinetics of gentamicin, amikacin, tobramycin, kanamycin and apramycin. The allometric equations shown in our study provide a basis to estimate dose intervals for mammals and birds for which specific information is lacking.