Parenteral versus oral antibiotic therapy.

The past decade has seen the increased use of oral therapy for a variety of serious infections that were previously treated exclusively by parenteral therapy. A variety of clinical trials in patients with pneumonia, urinary tract infections, skin and soft tissue infections, osteomyelitis, and bacteremia have demonstrated equal efficacy between oral and parenteral therapy. Much of this success is due to the availability of new oral agents, such as the fluoroquinolones and cephalosporins, with enhanced activity against gram-negative bacilli and improved pharmacokinetics. Oral therapy with certain of these drugs provides the same therapeutic serum levels required for efficacy that are obtained with parenteral therapy, that is, a 24-hour AUC/MIC above 125 for fluoroquinolones and levels constantly above the MIC for cephalosporins and other beta-lactams. Oral therapy can also reduce the costs of antimicrobial therapy.