Kinetics of ceftazidime during plasmapheresis

The influence of plasmapheresis (PA) on the elimination kinetics of ceftazidime (Cef) has been investigated. A single dose of Cef was administered intravenously to 11 patients with autoimmune diseases and varying degrees of renal impairment (Group I CLCR less than 50 ml/min, Group II CLCR greater than 50 ml/min). In Groups I and II the mean total clearance of Cef (CL) was 30 and 116 ml/min-1, respectively. The elimination half-life (t1/2 beta) and the volume of distribution (V) were significantly higher in Group I than in Group II (11.9 vs 2.0 h, 27.1 vs 18.5 l). PA had no influence on the plasma level-time profile of Cef. The amount of Cef recovered from separated plasma accounted for only 2 to 9% of the administered dose, being particularly low in patients with normal renal function (4.6%). Thus, since elimination of Cef via PA is negligible, dosage calculations should be based solely on renal function.