Treating outpatients with continuous infusions of flucloxacillin, cefepime, vancomycin, and piperacillin/tazobactam using elastomeric pumps was effective and safe, according to data published in Journal of Antimicrobial Chemotherapy.
The clinical outcomes, adverse events, and antibiotic plasma concentrations were assessed for 150 individuals at the outpatient parenteral antimicrobial therapy unit of the University Hospital of Lausanne between December 2013 and January 2017 (ClinicalTrials.gov identifier NCT03221140). Participants received continuous infusion via elastomeric pump of flucloxacillin (70), cefepime (36), vancomycin (32), and piperacillin/tazobactam (12).
Results showed the calculated free fractions of each antibiotic were above the epidemiological cutoff values for resistance (ECOFF) of the treated microorganisms in 92% of measurements. In 143 participants (95%), cure was achieved 3 months after finishing treatment. Only 4 patients required readmission, 3 relapsed, and 16 had an adverse event, but none were of severity grade 4 or 5. Among patients with unsuccessful treatment, the ratio of free antibiotic plasma concentration/ECOFF was never <1.
Statistical power regarding whether the ratio of free concentration over the ECOFF of the bacteria to be treated would be a predictor of either treatment failure or adverse reactions was limited in this study, and no conclusion could be drawn. It is also possible, therefore, that antibiotic plasma levels do not guarantee sufficient tissue exposure. In addition, the free fraction of drugs, which was used to extrapolate free antibiotic concentrations, is known to be difficult to establish and vary highly among patients, depending on patient characteristics. It was also noted that the number of patients with unfavorable outcomes may be underestimated, as only the original hospital records were consulted for the occurrence of relapses and readmissions.
Investigators concluded, however, that this treatment method is safe and effective and that “the measured antibiotic plasma concentrations confirmed adequate drug concentration exposure for the vast majority of patients.”
Voumard R, Gardiol C, André P, et al. Efficacy and safety of continuous infusions with elastomeric pumps for outpatient parenteral antimicrobial therapy (OPAT): an observational study [published online July 4 2018]. J Antimicrob Chemother. doi: 10.1093/jac/dky224