Salvage treatment of methicillin-resistant staphylococcal endocarditis with ceftaroline: a multicentre observational study.

There are scarce data on the dosing of antibiotics in patients undergoing renal replacement therapy. 7 Our data suggest that extended dialysis eliminates colistin effectively and to a larger extent than regular intermittent outpatient haemodialysis. This is in line with recent data on two critically ill patients undergoing a modern type of intermittent dialysis (1.6 m 2 polymethylacrylate membrane, blood/dialysate flow 300/500 mL/min, duration 4 h), in whom a CMS dialyser clearance of 90 mL/min was reported. 8 Li et al. 9 described a dialyser clearance of 11.9 mL/min for colistin and 11.2 mL/min for CMS in one critically ill patient undergoing continuous venovenous haemodiafiltration, which due to its continuous mode would remove approximately the same amount of the drug. Lastly, dialyser clearance in five patients receiving continuous venovenous haemodiafiltration was recently reported to be 72 mL/min for colistin and 32 mL/min for CMS. 10 Thus, dosing colistin as recommended during regular haemodi-alysis is inadequate and would result in a significant under-dosing, which could be associated with a substantial risk, especially in critically ill patients in the ICU. A dose of 3 million units every 8 h seems to be adequate for patients undergoing daily extended dialysis for 9 h a day with a high flux 1.3 m 2 dialyser. This dose of 9 million units per day did not lead to accumulation of the drug. 2 Couet W, Gregoire N, Gobin P et al. Pharmacokinetics of colistin and colistimethate sodium after a single 80-mg intravenous dose of CMS in young healthy volunteers. 4 Curitis JR, Eastwood JB. Colistin sulphomethate sodium administration in the presence of severe renal failure and during haemodialysis and peritoneal dialysis. 5 Gobin P, Lemaitre F, Marchand S et al. Assay of colistin and colistin methanesulfonate in plasma and urine by liquid chromatography-tandem mass spectrometry. 6 Bode-Boger SM, Schopp B, Troger U et al. Intravenous colistin in a patient with serious burns and borderline syndrome: the benefits of therapeutic drug monitoring. 7 Scoville BA, Mueller BA. Medication dosing in critically ill patients with acute kidney injury treated with renal replacement therapy. Nation RL et al. Pharmacokinetics of colistin methanesulfonate and colistin in a critically ill patient receiving continuous venovenous hemodiafiltration. 10 Karvanen M, Plachouras D, Friberg LE et al. Colistin methanesulfonate and colistin pharmacokinetics in critically ill patients receiving continuous venovenous hemodiafiltration. Sir, b-Lactam agents have been the main antibacterial agents used for the treatment of …