Unnecessary use of fluoroquinolone antibiotics in hospitalized patients

Background: Fluoroquinolones are among the most commonly prescribed antimicrobials and are an important risk factor for colonization and infection with fluoroquinolone-resistant gram-negative bacilli and Clostridium difficile infection (CDI).

Objective: To determine the frequency of, reasons for, and adverse effects of inappropriate fluoroquinolone use in a tertiary-care academic medical center.

Methods: We performed a prospective, observational study of 226 randomly-selected adult inpatients receiving fluoroquinolone antimicrobial therapy during a 6-week period. Fluoroquinolone therapy was determined to be necessary or unnecessary based on published guidelines or standard principles of infectious diseases. Adverse effects were determined based on chart review 6 weeks after completion of therapy.

Results: Of 1,773 fluoroquinolone days-of-therapy, 659 (37%) were deemed unnecessary. The most common reasons for unnecessary therapy included administration of antimicrobials for non-infectious or non-bacterial syndromes (284 days-of-therapy) and administration of antimicrobials for longer than recommended durations (212 days-of-therapy). The most common syndrome associated with unnecessary therapy was urinary tract infection or asymptomatic bacteriuria (30% of all unnecessary days-of-therapy). In comparison to patients receiving necessary fluoroquinolone regimens, those receiving unnecessary regimens were older (median age, 65 vs 59, p = 0.002) and more likely to be cared for by family practice or rehabilitation medicine services (p ≤0.028). Twenty-seven percent (60/227) of all regimens were associated with adverse effects possibly attributable to therapy, including gastrointestinal adverse effects (14% of regimens), colonization by resistant pathogens (8% of regimens), and CDI (2% of regimens).

Conclusions: In our institution, more than one-third of all fluoroquinolone days-of-therapy were unnecessary. Interventions that focus on improving adherence with current guidelines for duration of antimicrobial therapy and for management of urinary syndromes could markedly reduce overuse of fluoroquinolones.