Aztreonam: a review of the first monobactam

Aztreonam represents the first synthetic monobactam marketed in the United States and is being viewed as a nontoxic alternative to the aminoglycosides. Advantages of aztreonam over the aminoglycosides include lack of ototoxicity and nephrotoxicity and better penetration into the CSF. Additional advantages include its use in penicillin and cephalosporin allergic patients. Disadvantages of aztreonam compared to the aminoglycosides include the cost of the drug (50 times more expensive than gentamicin), the lack of post antibiotic effect, resistance to P. aeruginosa, and lack of significant activity against Enterobacter cloacae and E. aerogenes. There are insufficient clinical trials to document the superiority of aztreonam over the "gold standard" therapy for gram-negative infections--the aminoglycosides. The restricted anti-microbial spectrum of aztreonam has been proposed as an advantage. Theoretically, this would permit targeting of a gram-negative pathogen with minimal disruption of the (largely anaerobic) intestinal flora. In fact, use of this drug has been associated with colonization of gram-positive organism, especially enterococci. Although aztreonam appears to be an excellent antibiotic, its use has been limited by its relatively high cost, narrow spectrum of activity, and the availability of numerous alternative agents.