Pharmacokinetics of gentamicin administered intravenously to water-deprived goats

The pharmacokinetics of gentamicin sulphate administered intravenously (3 m g/kg body weight) were studied in dehydrated Nubian goats, which had lost a n average of 7.2, 10.4 or 12.8% of their body weights owing to water depriv ation for 2, 3 or 4 days, respectively. The pharmacokinetic parameters were described by a two-compartment open model. A significant decrease was obse rved in total body clearance (p < 0.05) following strict water deprivation with an average 7.2% loss in body weight. No statistically significant chan ges were found in the distribution parameters of the drug at this dehydrati on level. In dehydrated goats which had lost about 10.4 or 12.8% body weigh t, mean plasma concentrations were significantly higher (p < 0.05). Clearan ce was decreased (p < 0.001) corresponding to a substantial increase in the half-life of elimination. Reduction was observed in the volume of distribu tion at steady state (Vdss) compared with normally hydrated goats (p < 0.05 ). The alterations in the pharmacokinetics of gentamicin observed in the pr esent study justify the need for an adjustment of the gentamicin therapeuti c dosage regimen in dehydrated animals. (C) 1999 Elsevier Science B.V. All rights reserved.