Pharmacokinetics and tissue penetration of azthreonam

Six healthy male volunteers received 1 g of azthreonam each as an intravenous injection. Serial blood and cantharides-induced blister fluid samples were taken over the next 8 h. Urine samples were collected over 24 h. The concentration of azthreonam in serum was about 50 micrograms/ml at 0.5 h after injection and fell to 2 to 3 micrograms/ml at 8 h; the serum half-life was 1.93 h, and the volume of distribution was equivalent to 12% of the mean body weight. The plasma clearance was 89.0 ml/min, 73.7% of the dose being recovered in the urine within 24 h. Azthreonam rapidly penetrated blister fluid, reaching a maximum of 25.4 micrograms/ml at 1.8 h after administration.