The pharmacokinetic behaviour of ceftazidime in man and the relationship between serum levels and the in vitro susceptibility of clinical isolates.

The pharmacokinetic properties of ceftazidime in volunteers and in vitro activity against a wide range of human pathogens were investigated. Ceftazidime was well tolerated by i. m. and i. v. routes in single doses of 500 mg to 2 g and in repeat doses of 2 g tds for ten days. The half-life averaged 1.9 h and urinary recovery over 24 h averaged 83%. There was good agreement between HPLC and microbiological assay and no metabolites were detected by either method. Correlation of serum levels with MIC90 values suggested that the 500 mg i. m. dose given bd should be suitable for fully sensitive enterobacteria and 1 g i. m. or i. v. bd should be effective against most genera. It may be necessary to use 1 g or 2 g i. v. doses tds when treating infections due to Staphylococcus aureus, Pseudomonas aeruginosa or Acinetobacter spp. These higher doses may be required when there is impaired penetration into the site of infection, when the infection is complicated by underlying pathology or in a life-threatening situation.