Differenciation between «new cephalosporin and «third generation cephalosporin depends on increase resistance to gram negative betalactamases, low MIC to enterobacteriacae and some gram negative rods, diffusion with high concentrations in sites not accessible to precedent cephalosporins. This beneficit has to be compared, not only to other cephalosporins, but also to carbapenems, monobactams, fluoroquinolones. These new cephalosporims have a variable half-life : less than two hours (cefoperazone, latamoxef), more than eight hours (ceftriaxon). They have a variable biliary elimination : low (cefotaxime, cefmenoxime, ceftizoxine, ceftazidime), notable (ceftriaxon, latamoxef), predominant (cefoperazone). Indesirable effects are at the same rate than with other beta lactamines, but those with methyl-thio-tetrazol (cefmenoxime, cefoperazone, latamoxef) are responsible for antabuse effect and coagulation disorders. Cost for ten treatment days moves more than 50 % from one group (cefoperazone, ceftriaxon) to a second (latamoxef ceftizoxime, cefotaxime, cefsulodin). Benefit and contraints are the guidelines of indications : hospital use with respect of the responsible strain, hospital ecology, patient immunocompetence and, then, monotherapy or association. © 1986.
