Optimal timing of oral fosfomycin administration for pre-prostate biopsy prophylaxis

Nathaniel J. Rhodes, Bradley J. Gardiner, Michael N. Neely, M. Lindsay Grayson, Andrew G. Ellis, Nathan Lawrentschuk, Albert G. Frauman, Kelly M. Maxwell, Teresa R. Zembower, Marc H. Scheetz*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

31 Scopus citations


Objectives: As the optimal administration time for fosfomycin peri-procedural prophylaxis is unclear, we sought to determine optimal administration times for fosfomycin peri-procedural prophylaxis. Methods: Plasma, peripheral zone and transition zone fosfomycin concentrations were obtained from 26 subjects undergoing transurethral resection of the prostate (TURP), following a single oral dose of 3 g of fosfomycin. Population pharmacokinetic modelling was completed with the Nonparametric Adaptive Grid (NPAG) algorithm (Pmetrics package for R), with a four-compartment model. Plasma and tissue concentrations were simulated during the first 24 h post-dose, comparing these with EUCAST susceptibility breakpoints for Escherichia coli, a common uropathogen. Results: Non-compartmental-determined pharmacokinetic values in our population were similar to those reported in the package insert. Predicted plasma concentrations rapidly increased after the first hour, giving more than 90% population coverage for organisms with an MIC ≤4 mg/L over the first 12 h post-dose. Organisms with higher MICs fared much worse, with organisms at the EUCAST breakpoint being covered for <10% of the population at any time. Transitional zone prostate concentrations exceeded 4 mg/L for 90% of the population between hours 1 and 9. Peripheral zone prostate concentrations were much lower and only exceeded 4 mg/L for 70% of the population between hours 1 and 4. Conclusions: Until more precise plasma and tissue data are available, we recommend that fosfomycin prophylaxis be given 1-4 h prior to prostate biopsy. We do not recommend fosfomycin prophylaxis for subjects with known organisms with MICs >4 mg/L.

Original languageEnglish (US)
Article numberdkv067
Pages (from-to)2068-2073
Number of pages6
JournalJournal of Antimicrobial Chemotherapy
Issue number7
StatePublished - Dec 6 2015


  • Drug administration schedule
  • Pharmacokinetics
  • Prostate

ASJC Scopus subject areas

  • Pharmacology
  • Microbiology (medical)
  • Infectious Diseases
  • Pharmacology (medical)


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