azlocillin and Anuria

The influence of continuous arteriovenous hemofiltration on the pharmacokinetics of azlocillin was examined in eight anuric intensive care patients, each of whom received a short infusion of 5.0 g azlocillin. Azlocillin concentrations in blood were measured simultaneously in the afferent and efferent loops of the amicon Dia 20 hemofilter and in the ultrafiltrate by means of an agar diffusion technique. Pharmacokinetic parameters were calculated by a computer program based on a two compartment model. We found that the elimination half-life of azlocillin ranged between 218.8 and 342.8 min, a result comparable to those of other investigators, who found similar elimination half-lives in anuric patients. During an observation period of 270 min, only 0.2-1.1% of the total dose of azlocillin was eliminated by way of the hemofilter. Apparently, continuous arteriovenous hemofiltration has no clinically relevant implications for the dosage or the dosage intervals of this antibiotic. On the other hand, azlocillin was taken up by the amicon Dia 20 hemofilter during the infusion. After the infusion was stopped the filter released azlocillin to blood and ultrafiltrate. The ratio of concentration in ultrafiltrate to plasma concentration in the afferent loop of the hemofilter was higher for about 45 min during the elimination phase than during the infusion. The volume of distribution was much larger (mean 28.5 l) than that found by other investigators. Therefore, the amicon-Dia 20 hemofilter seems to function as an additional distribution space.(ABSTRACT TRUNCATED AT 250 WORDS)

Topics: Anuria; Azlocillin; Hemofiltration; Humans