Polymyxin B Pharmacokinetics in Adult Cystic Fibrosis Patients

Sean N. Avedissian, Cristina Miglis, Christine J. Kubin, Nathaniel J. Rhodes, Michael T. Yin, Serge Cremers, Michelle Prickett, Marc H. Scheetz

Research output: Contribution to journalArticlepeer-review

32 Scopus citations


Objectives: Polymyxin B pharmacokinetics (PK) in adults with cystic fibrosis (CF) are not well described. The goals of this pilot study were to identify a PK model for patients with CF receiving polymyxin B with exploration of covariate relationships of the PK parameters, to compare polymyxin B PK parameters in adults without CF, and to probe exposures associated with different dosing schemes through simulation. Methods: Adult patients with CF treated with polymyxin B at New York-Presbyterian Hospital had PK samples measured by liquid chromatography–mass spectrometry (MS)/MS. Multiple PK models were fit utilizing Pmetrics for R. Model covariates considered included: age, total body weight, creatinine clearance, albumin, and body mass index. PK parameters in CF patients were compared with PK parameters for 53 adults without CF who were receiving polymyxin B from the same institution. Simulations with target exposure (area under the curve)/minimum inhibitory concentration (MIC) of 20 mg*L/h were conducted for different dosing schemes and MIC ranges. Main Results: Nine patients with CF received between 58 and 240 mg of polymyxin B (median 1.47 mg/kg/dose [IQR (1.43–1.65)]). A two-compartment model adjusting polymyxin B clearance for patient CrCl was better than a standard two-compartment model (p=0.004) in CF patients. When compared to PK parameters for patients without CF, PK parameters of polymyxin B in CF were similar (p>0.05). Simulations for plasma concentrations showed all regimens performed adequately at MICs between 0.03125 and 0.125 mg/L but not at increasing MICs of 1 and 2 mg/L. Conclusions: In this pilot study of polymyxin B PK in adults with CF, the PK parameters of polymyxin B were mostly similar to adults without CF. We observed a potential association between CrCl and polymyxin B clearance, which stands in contrast to the general adult population. However, this observation requires further study. Additional studies focusing on optimal and safe polymyxin B dosing in CF are needed.

Original languageEnglish (US)
Pages (from-to)730-738
Number of pages9
Issue number7
StatePublished - Jul 2018
Externally publishedYes


  • cystic fibrosis
  • pharmacokinetics
  • polymyxin B

ASJC Scopus subject areas

  • Pharmacology (medical)


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