Review of single- and multiple-dose pharmacokinetics of the monobactam, aztreonam (SQ 26,776) in healthy subjects.

Aztreonam (SQ 26,776) is a new, completely synthetic, monocyclic beta-lactam antibiotic with potent activity against most aerobic gram-negative bacteria. The pharmacokinetics of single intravenous doses of 125-4,000 mg, single intramuscular doses of 250-1,000 mg, and multiple intravenous and intramuscular doses of 500 and 1,000 mg q.8 h during 7 days, were studied in 90 healthy male subjects. The half-life was 1.7, apparent volume of distribution 0.2 liters/kg, serum protein binding 56%, and urinary excretion 60-70% of the dose. No significant accumulation or change in pharmacokinetics of aztreonam was found during q.8 h dosing. Small amounts of the biologically inactive open beta-lactam ring metabolite, SQ 26,992, were found in the urine. Aztreonam level in serum and urine after 500- to 2,000-mg doses were potentially therapeutic for most Enterobacteriaceae and Pseudomonas aeruginosa.