Pharmacokinetics of phosphomycin during haemofiltration

The pharmacokinetics of phosphomycin were studied in 10 adult patients with terminal renal impairment during a 4 h haemofiltration session. A single i.v. dose of 30 mg/kg of the antibiotic was administered to each patient at the beginning of the haemofiltration session. The half-life of the slow disposition phase (t 1/ 2z ) showed an average value of 4.05 +/- 1.77 h, much lower than that established in patients who did not undergo any purification techniques. Serum phosphomycin concentrations at the input and the output of the haemofilter at the end of the session were, respectively, 26.65 and 19.13 micrograms/ml. During haemofiltration, 64.90% of the original dose was eliminated. In this kind of patient we recommend a dose of 30 mg/kg at the beginning and at the end of each haemofiltration session for interfiltration periods of 48 h.