title: Intermittent intravenous piperacillin pharmacokinetics in automated peritoneal dialysis patients.
abstract: BACKGROUND
  Use of intermittent antibiotic dosing is increasing in the treatment of peritoneal dialysis (PD)-related peritonitis. We studied the pharmacokinetics of intravenous (i.v.) piperacillin in automated PD patients.
  
  
  METHODS
  Eight patients (3 males, 5 females) were recruited and received a single i.v. dose of piperacillin (35 mg/kg actual body weight). Blood and dialysate samples were collected at the beginning, middle, and end of dwells 1-3 (on cycler), and end of dwells 4-5 (off cycler) for a 24-hour period. Baseline and 24-hour urine samples (nonanuric patients, n = 7) were collected. Pharmacokinetic parameters were calculated assuming a one-compartment model. Glomerular filtration rate (GFR) and piperacillin clearance (CL) values were normalized to 1.73 m2.
  
  
  RESULTS
  The patients were 49.5 +/- 10.1 years of age (mean +/- SD) and had been receiving PD for a median of 3 months (range 2-66 months). Dwell times were 2.25 +/- 0.06 hours on cycler and 7.26 +/- 0.14 hours off cycler. Piperacillin half-life was not statistically different on or off the cycler (on cycler 1.99 +/- 0.39 hr, off cycler 4.39 +/- 5.4 hr; p = 0.12) and remained insignificant, even accounting for an outlier (on cycler 2.01 +/- 0.41 hr, off cycler 2.54 +/- 1.48 hr; p = 0.19). Piperacillin total CL (CL(T)) was 31.29 +/- 6.02 mL/minute. Renal CL (CL(R)) and PD CL (CL(PD)) accounted for 8.8% and 16.8% of CL(T); CL(R) correlated well with GFR (CL(R) = 0.86 GFR + 0.1; p < 0.00003). Mean piperacillin serum and dialysate end-of-dwell concentrations were above minimum inhibitory concentration of susceptible organisms (8 microg/mL) for the three cycler exchanges only. Serum and dialysate concentrations predicted using a one-compartment model suggest that i.v. piperacillin 4000 mg would provide adequate concentrations for susceptible organisms over a 12-hour period.
  
  
  CONCLUSIONS
  The current i.v. piperacillin dosing recommendations of 4000 mg every 12 hours for PD-related peritonitis are appropriate for patients on automated PD. Intermittent intraperitoneal piperacillin is not recommended.
authors.affiliation: School of Pharmacy, University of Missouri-Kansas City, USA. ManleyH@UMKC.edu
authors.forename: H J
authors.initials: HJ
authors.lastname: Manley
authors.forename: G R
authors.initials: GR
authors.lastname: Bailie
authors.forename: R
authors.initials: R
authors.lastname: Frye
authors.forename: M D
authors.initials: MD
authors.lastname: McGoldrick
mesh_terms: D000328:Adult; D005260:Female; D006801:Humans; D007262:Infusions, Intravenous; D008297:Male; D008875:Middle Aged; D010406:Penicillins / Q000008:administration & dosage / Q000493:pharmacokinetics*; D010530:Peritoneal Dialysis / Q000379:methods*; D010878:Piperacillin / Q000008:administration & dosage / Q000493:pharmacokinetics*
chemical_list: D010406:Penicillins; D010878:Piperacillin