Context: Most sore throats are due to viral upper respiratory tract infections. Group A beta-hemolytic streptococci (GABHS), the only common cause of sore throat warranting antibiotics, is cultured in 5% to 17% of adults with sore throat. The frequency of antibiotic use for pharyngitis has greatly exceeded the prevalence of GABHS, but less is known about specific classes of antibiotics used. Only penicillin and erythromycin are recommended as first-line antibiotics against GABHS.

Objectives: To measure trends in antibiotic use for adults with sore throat and to determine predictors of antibiotic use and nonrecommended antibiotic use.

Design, setting, and subjects: Retrospective analysis of 2244 visits to primary care physicians in office-based practices in the National Ambulatory Medical Care Survey, 1989-1999, by adults with a chief complaint of sore throat.

Main outcome measures: Treatment with antibiotics and treatment with nonrecommended antibiotics, extrapolated to US annual national rates.

Results: There were an estimated 6.7 million annual visits in the United States by adults with sore throat between 1989 and 1999. Antibiotics were used in 73% (95% confidence interval [CI], 70%-76%) of visits. Patients treated with antibiotics were given nonrecommended antibiotics in 68% (95% CI, 64%-72%) of visits. From 1989 to 1999, there was a significant decrease in use of penicillin and erythromycin and an increase in use of nonrecommended antibiotics, especially extended-spectrum macrolides and extended-spectrum fluoroquinolones (P<.001 for all trends). In multivariable modeling, increasing patient age (odds ratio [OR], 0.86 per decade; 95% CI, 0.79-0.94) and general practice specialty (OR, 1.54 compared with family practice specialty; 95% CI, 1.10-2.14) were independent predictors of antibiotic use. Among patients receiving antibiotics, nonrecommended antibiotic use became more frequent over time (OR, 1.17 per year; 95% CI, 1.11-1.24).

Conclusions: More than half of adults are treated with antibiotics for sore throat by community primary care physicians. Use of nonrecommended, more expensive, broader-spectrum antibiotics is frequent.