Pharmacokinetics and clinical efficacy of cefotaxime for the treatment of septicaemia in dogs

Considering the already known pharmacological features of cefotaxime, a study with two approaches of pharmacokinetics and clinical efficacy in septicaemic dogs was carried out. Pharmacokinetic variables were defined for doses of 10 mg/kg, and 20 mg/kg, utilising a quantitative bacteriological analysis. Values for half-life (T1/2 beta) at 10 mg/kg were 0.8, 1.48 and 1.52 h for the i.v., s.c. and i.m. routes, respectively. Corresponding values for the 20 mg/kg dose for the same routes were 0.8, 1.49 and 1.53 h, respectively. Relatively fast clearance (ranging from 0.58 to 0.64 L/kg/h) allowed a maximum dose interval of 12 h. The above-stated doses of cefotaxime were administered i.v. to 40 cases of septicaemia, clinically divided into 20 moderately severe cases treated with 10 mg/kg i.v., of cefotaxime bid, and 20 severe ones, treated with 20 mg/kg i.v. of cefotaxime bid. Injections continued until a previously defined criterion of 'clinically recovered' was obtained. Thereafter, a follow-up treatment was established using the same dose and dose-interval but through the s.c. route. Due to the apparent volumes of distribution obtained (ranging from 0.48 to 0.51 L/kg), considering the overall clinical efficacy obtained (90% for the 10 mg/kg dose and 75% for the 20 mg/kg dose), and due to the rapid improvement observed after a few doses of the drug (1.8 to 2.5 doses to 'clinical improvement'), it is safe to postulate such doses of cefotaxime as excellent choices for the treatment of septicaemia in dogs.