Clinical pharmacology of aztreonam in healthy recipients and patients: a review.

Serum and urinary concentrations of aztreonam after 0.5-g, 1-g, and 2-g doses are potentially therapeutic in patients with infections due to susceptible gram-negative organisms. Aztreonam is widely distributed at significant levels in body fluids and tissues. Levels exceeding the minimal inhibitory concentrations for most important gram-negative pathogens are attained in those anatomic locations in which infections are usually found. Aztreonam is eliminated primarily in the urine in unchanged form, although it is also secreted into the bile. The drug is also metabolized to a minor extent to an open-ring compound that is excreted in the urine and feces. No clinically noteworthy interactions have been found between aztreonam and cephradine, clindamycin, gentamicin, metronidazole, nafcillin, probenecid, or furosemide. The elimination of aztreonam may be significantly impaired by renal insufficiency; the dosage must be modified in patients with creatinine clearance rates of less than 30 ml/min. The monobactam can be eliminated efficiently by hemodialysis but to only a minor extent by peritoneal dialysis. Parenterally and orally administered aztreonam can selectively reduce the numbers of aerobic gram-negative bacteria in feces without notably altering the numbers of anaerobic organisms.