title: Changing use of antibiotics in community-based outpatient practice, 1991-1999.
abstract: BACKGROUND
  Judicious use of antibiotics can slow the spread of antimicrobial resistance. However, overall patterns of antibiotic use among ambulatory patients are not well understood.
  
  
  OBJECTIVE
  To study patterns of outpatient antibiotic use in the United States, focusing on broad-spectrum antibiotics.
  
  
  METHODS
  Cross-sectional survey in three 2-year periods (1991-1992, 1994-1995, and 1998-1999).
  
  
  METHODS
  The National Ambulatory Medical Care Survey, a nationally representative sample of community-based outpatient visits.
  
  
  METHODS
  Patients visiting community-based outpatient clinics.
  
  
  METHODS
  Rates of overall antibiotic use and use of broad-spectrum antibiotics (azithromycin and clarithromycin, quinolones, amoxicillin-clavulanate, and second- and third-generation cephalosporins). All comparisons were made between the first study period (1991-1992) and the final study period (1998-1999).
  
  
  RESULTS
  Between 1991-1992 and 1998-1999, antibiotics were used less frequently to treat acute respiratory tract infections, such as the common cold and pharyngitis. However, use of broad-spectrum agents increased from 24% to 48% of antibiotic prescriptions in adults (P < 0.001) and from 23% to 40% in children (P < 0.001). Use of broad-spectrum antibiotics increased across many conditions, increasing two- to threefold as a percentage of total antibiotic use for a variety of diagnoses in both adults and children. By 1998-1999, 22% of adult and 14% of pediatric prescriptions for broad-spectrum antibiotics were for the common cold, unspecified upper respiratory tract infections, and acute bronchitis, conditions that are primarily viral.
  
  
  CONCLUSIONS
  Antibiotic use in ambulatory patients is decreasing in the United States. However, physicians are increasingly turning to expensive, broad-spectrum agents, even when there is little clinical rationale for their use.
authors.affiliation: Division of Geriatrics, San Francisco Veterans Affairs Medical Center and University of California, San Francisco 94121, USA. mstein@itsa.ucsf.edu
authors.forename: Michael A
authors.initials: MA
authors.lastname: Steinman
authors.forename: Ralph
authors.initials: R
authors.lastname: Gonzales
authors.forename: Jeffrey A
authors.initials: JA
authors.lastname: Linder
authors.forename: C Seth
authors.initials: CS
authors.lastname: Landefeld
mesh_terms: D000328:Adult; D000553:Ambulatory Care; D000900:Anti-Bacterial Agents / Q000627:therapeutic use*; D000890:Anti-Infective Agents / Q000627:therapeutic use; D002648:Child; D003430:Cross-Sectional Studies; D011307:Drug Prescriptions; D004352:Drug Resistance, Microbial; D004363:Drug Utilization / Q000639:trends; D006801:Humans; D010818:Practice Patterns, Physicians'; D012141:Respiratory Tract Infections / Q000188:drug therapy; D014481:United States / Q000453:epidemiology
chemical_list: D000900:Anti-Bacterial Agents; D000890:Anti-Infective Agents