New drug evaluations: moxalactam (Moxam, Eli Lilly)

Moxalactam is a new 1-oxa-beta-lactam antibiotic that is similar in many respects to the third-generation cephalosporins. Moxalactam is exceptionally stable to beta-lactamase enzymes and inhibits most gram-negative aerobic bacteria, with the frequent exception of P. aeruginosa. Moxalactam is active against most B. fragilis organisms and appears to be an effective alternative to an aminoglycoside/clindamycin combination for patients with intraabdominal infections. Moxalactam penetrates through inflamed meninges and may become the drug of choice for gram-negative bacillary meningitis due to susceptible organisms. Moxalactam would be expected to be no more effective than the third-generation cephalosporins for other gram-negative infections, and it has not been clearly shown that these agents are as effective as aminoglycoside antibiotics for most serious gram-negative infections. Because of moxalactam's high cost, its potential for misuse, and its unknown long-term effects on microbial resistance patterns, as well as the lack of comparative efficacy studies for many infections, the hospital use of moxalactam should be closely monitored.