[Cefixime, the first oral third-generation cephalosporin].

In the early 1980's parenteral third generation cephalosporins changed the hospital use of antibiotics. The MICs of these cephalosporins are several dozen times lower than those of first or second generation cephalosporins for Enterobacteriaceae and they are much more beta-lactamase stable than second generation cephalosporins. After years of research, is has finally been possible to develop orally active compounds possessing the same antibacterial activity as parenteral third generation cephalosporins, either through the use of prodrugs, or by modifying the molecular structure of drugs. Cefixime is an example of the latter. The vinyl group at the 3-position of the cephem nucleus is responsible for the intestinal absorption of the intact molecule, primarily by a carrier-mediated transport mechanism. The aminothiazole ring and the R-oxyimino group on the side-chain at the 7-position are associated with an antibacterial activity similar to that of third generation cephalosporins. Thousands of adults have been treated by cefixime for lower respiratory tract, ear-nose-throat and urinary tract infections, showing that cefixime is a safe and effective antimicrobial agent. The major clinical indications for cefixime in adults are bronchial and pulmonary infections, acute otitis or sinusitis, acute pyelonephritis with no underlying uropathy, and complicated or uncomplicated lower urinary tract infections excluding prostatitis. In all cases, the dosage is 200 mg b.i.d.