Antimicrobial agents/therapy vancomycin

The clinician should have an understanding of in vivo antimicrobial agent disposition in order to select the most appropriate therapy for a given infection and to help monitor for clinical or bacteri-ologic efficacy. Serum concentration monitoring is the most common method used to attempt to maximize efficacy and minimize toxicity of antimicrobials. Since most antimicrobials are well tolerated at their usual doses, only a select few agents (e.g., aminoglycosides, chloramphenicol, and vancomycin) are monitored routinely in the current clinical environment. There are a number of direct and indirect methods that are used to quantify the concentration of antimicrobial in an experimental sample. 

The usual duration of therapy for peritonitis associated with CAPD is 10 to 14 days, but up to 3 weeks of therapy may be required. Antimicrobial therapy should be continued until dialysate fluid is clear, cultures are negative for 2 to 3 days, and the patient is asymptomatic. When parenteral agents are administered, the initial dose would be the same as that for patients with normal renal function, whereas subsequent doses should be much less or given less frequently for renally excreted agents and should account for possible loss through peritoneal dialysis. Serum concentrations should be performed for aminoglycosides and vancomycin. Some studies have demonstrated that for patients with spontaneous bacterial peritonitis associated with cirrhotic ascites, treatment duration may be as short as 5 days when ascitic fluid polymorphonuclear cell counts are used to guide treatment. 

Ingram PR, Lye DC, Fisher DA, Goh WP, Tam VH. Nephrotoxicity of continuous versus intermittent infusion of vancomycin in outpatient parenteral antimicrobial therapy. Int J Antimicrob Agents 2009 34(6) 570-4. 

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