[Biological bases for the use of ceftazidime in anti-infection therapy]

The author presents the main in vitro and pharmacokinetic characteristics of ceftazidime, a third generation cephalosporin. Ceftazidime has been shown to be highly stable to most plasmid--or chromosome--mediated beta-lactamases. Several studies have demonstrated that its spectrum includes Gram-positive cocci as well as most Gram-negative bacilli, including beta-lactamase producers. Moreover, it has good in vitro activity against Gram-negative aerobic bacteria (Pseudomonas spp., Acinetobacter spp.) and frequently exerts a synergistic bactericidal action when combined with an aminoglycoside. As a result, ceftazidime displays a high intrinsic in vitro activity against most of the "difficult" strains. Pharmacokinetic studies indicate that ceftazidime exhibits metabolic stability in vivo; its elimination halflife is 1.8 hours, and about 88 to 92 p. 100 of the dose is recovered in the 24-h urine. Its extravascular distribution is excellent, with high levels being achieved in most tissues and body fluids in man. These in vitro and in vivo properties of ceftazidime suggest that this new cephalosporin should be considered a promising antibiotic for the treatment of severe infections.