Review of the clinical pharmacology of the monobactam antibiotic aztreonam.

Serum and urine levels of aztreonam after 0.5, 1, and 2 g doses are potentially therapeutic for susceptible gram-negative organisms. Aztreonam is widely distributed in body fluids and tissues, and concentrations exceeding the minimal inhibitory concentrations of important gram-negative pathogens are attained in those compartments in which infections are most common. Aztreonam is eliminated primarily in the urine in unchanged form, although it is also secreted into the bile and is metabolized to a minor extent. Renal insufficiency may significantly impair the elimination of aztreonam, thus requiring modification of the dosage regimen. The monobactam can be cleared by hemodialysis but is only minimally cleared by peritoneal dialysis. Parenterally and orally administered aztreonam can selectively reduce the population of aerobic gram-negative bacteria in the gut without notably altering the number of anaerobic organisms.