Background:

Increasing fluoroquinolone (FQ) use has been described nationally and was observed locally at an urban trauma center, coinciding with increasing FQ resistance rates among P. aeruginosa. An antimicrobial management team assessed FQ use daily, reporting results quarterly, and noted an increase in inappropriate levofloxacin (L) prescribing. Excessive use of quinolones can contribute to development of resistance and increased antimicrobial costs. We implemented a formulary conversion from L to moxifloxacin (M) and ciprofloxacin(C). M use was targeted to CAP only, with C reserved predominantly for P. aeruginosa.

Objectives:

The objective was to assess the impact of the conversion on appropriateness of FQ use, cost of FQ use, cost of all antibiotics, and resistance.

Methods:

We conducted an interventional study comparing the 12 months prior to and after the formulary conversion. Appropriateness of FQ use was defined based on criteria defined by the antimicrobial subcommittee. Endpoints assessed were FQ use, FQ appropriateness, FQ costs, total antibacterial use, and total antibacterial costs.

Results:

After conversion, total fluoroquinolone use decreased from 49 DDDs/1000 pt days to 33; respiratory FQ use from 25 to 10, and ciprofloxacin use remained stable, 22 to 24. Adherence to criteria improved for all FQs (65% increased to 76%, P < 0.001), respiratory FQs (67 up to 88%, P < 0.001), and for ciprofloxacin (54 up to 62%). Formulary conversion also corresponded with a decrease in FQ expenditures: preintervention = $607, Post = $327 (USD per 1000 pt days). A modest increase was seen in costs of cephalosporins ($2085 up to $2542) and macrolides ($1109 up to $1277). These data correspond to an estimated annual savings of $20 000 our hospital, or $132 500 when extrapolated to our entire 2000-bed medical center. Total antibacterial expenditures for the hospital decreased from $646 000 to $594 000 for the two study periods. Resistance analysis will be performed and reported once 2003 data is complete.

Conclusion:

A targeted approach to formulary FQ management improved appropriateness of FQ use and decreased cost.