Changing use of antibiotics in community-based outpatient practice, 1991-1999

Ann Intern Med. 2003 Apr 1;138(7):525-33. doi: 10.7326/0003-4819-138-7-200304010-00008.


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.

Design: Cross-sectional survey in three 2-year periods (1991-1992, 1994-1995, and 1998-1999).

Setting: The National Ambulatory Medical Care Survey, a nationally representative sample of community-based outpatient visits.

Patients: Patients visiting community-based outpatient clinics.

Measurements: 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.

Publication types

  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Adult
  • Ambulatory Care
  • Anti-Bacterial Agents / therapeutic use*
  • Anti-Infective Agents / therapeutic use
  • Child
  • Cross-Sectional Studies
  • Drug Prescriptions*
  • Drug Resistance, Microbial
  • Drug Utilization / trends
  • Humans
  • Practice Patterns, Physicians'*
  • Respiratory Tract Infections / drug therapy
  • United States / epidemiology


  • Anti-Bacterial Agents
  • Anti-Infective Agents