Study on the relationship between pharmacokinetics and antibacterial activity: comparison between ceftriaxone and cefotaxime within the respiratory tract.

The aim of this research was to collect precise data on the antibacterial activity of ceftriaxone and cefotaxime in the respiratory tract. The diffusion into pulmonary tissue and bronchial secretion and the antibacterial activity of the two antibiotics were evaluated in vivo by means of the inhibitory quotient. Ceftriaxone administered at a dosage of 1 g (i.m.) every 24 h resulted in antibacterial levels against the sensitive pathogens over a period of 24 h after each dose. The antibacterial protection afforded by cefotaxime, given at the dosage of 1 g (i.m.) every 12 h, was not as marked and did not extend over the interval between two administrations.