Crossover study of the pharmacokinetics of ceftriaxone administered intravenously or intramuscularly to healthy volunteers.

The pharmacokinetics of ceftriaxone were investigated in six healthy adults. One-gram doses were administered either intramuscularly or intravenously in a crossover design study. Mean peak ceftriaxone concentrations in plasma of 79.2 and 123.2 micrograms/ml were achieved with intramuscular injection and intravenous infusion, respectively, with plasma half-lives of 5.4 and 5.8 h. The urinary recovery of ceftriaxone in the first 24 h was 37% after intravenous infusion and 25% after intramuscular injection.