Metronidazole kinetics in patients with acute renal failure on dialysis: a cumulative study.

Nine patients with acute renal failure who were undergoing dialysis at intervals depending on clinical state were injected with metronidazole, 7.5 mg . kg-1 iv every 8 hr. Plasma samples were drawn during the 8 hr after the first infusion, during the first dialysis session, and during the course of the fourth infusion after the first three dialysis sessions. Metronidazole and its two main metabolites (alcohol [M1] and acid [M2]) were assayed by HPLC. The plasma t 1/2 of metronidazole (6.8 hr) is of the same order as that in healthy subjects. M1 and M2 plasma levels increased continuously until the next infusion. Dialysis clearances of metronidazole and its metabolites were about 60 ml . min-1; 25% of metronidazole in the body at the beginning of hemodialysis was eliminated. The corresponding apparent t 1/2 s are 3.3 hr (metronidazole), 8.0 hr (M1), and 7.9 hr (M2). In patients with acute renal disease under hemodialysis, there was no cumulation of metronidazole and its metabolites; hence there is no need for change in dosage regimen.