WASHINGTON — Inconsistent and unclear guidelines may be contributing to overprescribing of fluoroquinolones to treat community-acquired pneumonia, said Conan MacDougall, Pharm.D., and colleagues in a poster presentation at the Interscience Conference on Antimicrobial Agents and Chemotherapy.
Treatment of community-acquired pneumonia (CAP) is one of the primary indications for fluoroquinolones for both inpatients and outpatients, according to guidelines issued by the Infectious Diseases Society of America (IDSA).
“[Fluoroquinolone] resistance, while generally low, appears to be increasing in Streptococcus pneumoniae as well as among gram-negative organisms. Thus, overuse and inappropriate use may compromise the future efficacy of this class of antibiotics,” reported the research team led by Dr. MacDougall, formerly with the department of clinical pharmacy at the University of California, San Francisco, but now is an infectious diseases fellow at Virginia Commonwealth University, Richmond.
The researchers did a retrospective, observational database review of pharmacy claims from four managed care organizations in Colorado from March 2000 to March 2003. A total of 4,538 patients were studied; 35% were aged 18-44 years, 35% were aged 45-64 years, and 30% were aged 65 or older. More than half of the patients (54%) were women. All had a primary diagnosis of CAP with no significant comorbidity. Seventy-two percent of patients were treated by a family physician and 26% were treated by an internist. The remaining 2% were seen by other specialists.
Floroquinolone use in this population rose 62% from 2000 to 2002, while macrolide use dropped 25% in the same time period.
Internists tended to prescribe the drugs more often than did family physicians, and patients aged older than 65 years received fluoroquinolones more often than did younger patients.
The rise in fluoroquinolone use among older patients may be appropriate since these patients are at higher risk of having drug-resistant S. pneumoniae; however, increased prescribing of fluoroquinolones for younger patients with no cormorbidities who are a low risk of treatment failure is cause for concern.
In 2001, CAP treatment guidelines were issued by the American Thoracic Society, the Centers for Disease Control and Prevention, and the Canadian Thoracic and Infectious Diseases Societies, in addition to IDSA. All four groups recommended macrolides and doxycycline as first-line therapy for CAP, but differed on indications for fluoroquinolone use. The CDC included beta-lactam antibiotics among first-line choices, while the IDSA included fluoroquinolones.
The American Thoracic Society and the Canadian Thoracic and Infectious Diseases Societies recommend fluoroquinolones for all inpatients, with or without the addition of a beta-lactam.
In its 2003 update to “Guidelines for CAP in Adults,” the IDSA recommends using a fluoroquinolone alone as first-line therapy only for adult outpatients who have had recent antibiotic therapy, all adult inpatients, and nursing home residents. For previously healthy adult outpatients, the guidelines now recommend first trying a macrolide or doxycycline.
The conference was sponsored by the American Society for Microbiology.