Table. Randomized, placebo-controlled trials of antibiotic treatment in adults with acute bronchitis.*

Study, Year (Reference)	Location	Participants	Interventions	Outcomes
Stott and West, 1976 (42)	United Kingdom	Persons >14 years of age with cough producing purulent sputum for ≤1 week	Doxycycline, 200 mg on day 1, then 100 mg/d for 9 days	For average days of daytime cough, yellow spit, “off color” spit, nighttime cough, runny nose, clear spit, sore throat, general aches and pains, headache, vomiting, and days of missed work, differences between placebo (n = 130) and antibiotic (n = 104) groups were nonsignificant; fewer patients in antibiotic group had runny nose at day 7 (P < .05); no difference in cough, purulent sputum, feeling unwell, and days of missed work; no difference among smokers; smaller proportion of patients with upper respiratory tract infection in doxycycline (13%) vs. placebo group (25%) at 6 months; no difference in subsequent lower respiratory tract infections, other infections, or asthma
Franks and Gleiner, 1984 (47)	Rochester, New York	Persons >14 years of age with productive cough for <15 days	Trimethoprim-sulfamethoxazole (160 mg/800 mg) twice daily for 7 days	“Mean” number of patients with cough over 7 days, 99% (n = 29) in placebo group vs. 93% in the antibiotic group (n = 25) (1-tailed P = .05); “mean” number of patients recording night cough over 7 days, 84% vs. 56% (P = .003); mean temperature, 37.3°C vs. 36.9°C; no difference in cough frequency, cough amount, activity level, time to return to work, and use of other symptomatic medications
Williamson, 1984 (44)	Columbia, Missouri	Persons 18–65 years of age with productive cough of any duration; patients with oral temperature >39.5°C excluded	Doxycycline, 100 mg twice daily on day 1, then 100 mg/d for 7 days	Average duration of cough, 18 days in placebo group (n = 32) vs. 20 days in antibiotic group (n = 37); difference in absence from work, 0.6 days vs. 1.5 days (P = .03); days of fever, days of purulent sputum mean symptom scores, antibiotic treatment at follow-up visit, and unscheduled return visits not significantly different between groups
Brickfield et al, 1986 (46)	Fairfax, Virginia	Persons 18–65 years of age with productive cough illness for ≤2 weeks	Erythromycin, 333 mg three times daily for 7 days	Mean daily symptom scores for each of 7 days favored placebo (n = 25) for 4 comparisons and antibiotic (n = 27) for 6 comparisons; at P = .05, one would expect 7 statistically significant differences by chance alone
Dunlay et al, 1987 (48)	Michigan	Persons ≥18 years of age with productive cough of any duration	Erythromycin, 333 mg three times daily for 10 days	Mean total symptom score over 10 days, about 2.25 in placebo group (n = 24) vs. 1.8 in antibiotic group (n = 24) (P < .01); proportion of patients with congestion at day 10, 75% vs. 38%; proportion of patients taking cough or cold medicines at day 10, 38% vs. 3% (P < .05); no difference between groups for day cough, night cough, productive cough, sore throat, feeling poor or unable to work or carry out daily routine at day 10; no differences among smokers
Scherl et al, 1987 (50)	Kentucky	Persons >12 years of age with self-described cough producing purulent sputum for <2 weeks	Doxycycline, 100 mg twice daily on day 1, then 100 mg/d for 7 days	Mean (± SD) duration of cough, 10.8 ± 1.2 days in placebo group vs. 9.4 ± 1.5 days in antibiotic group; mean duration of sputum, 10.4 ± 1.4 days vs. 8.5 ± 1.5 days
Verheij et al, 1994 (45)	Leiden, The Netherlands	Persons ≥18 years of age	Doxycycline, 200 mg on day 1, then 100 mg/d for 10 days	Proportion of patients with “frequent” daytime cough, 39% in placebo (n = 69) group vs. 21% in antibiotic group (n =71) (P < .05); no difference in proportion with nighttime cough or productive cough; proportion of patients who felt ill, 19% vs. 35%, but no difference in proportion who looked ill; no difference in proportion of patients in whom clinical condition improved; mean duration of daytime cough, 6.2 days vs. 4.7 days (P < .01), but no difference in mean nighttime cough, productive cough, feeling ill, or impaired daily activities; subgroup analyses among patients ≥55 years of age or older and those who had very frequent cough and felt ill showed statistically significant differences; at study entry, a greater proportion of patients in the antibiotic group felt ill
King et al, 1996 (43)	North Carolina	Persons ≥8 years of age with productive cough for ≤2 weeks	Erythromycin, 250 mg/d for 10 days	Self-reported cough frequency, general feeling of well-being chest congestion, and use of cough medicines did not differ between placebo (n = 42) and antibiotic (n = 49) groups; fewer days of work lost in antibiotic group (0.81 days vs. 2.16 days (P < .02); no differences among those with and without serologic evidence of mycoplasma infection
*All studies excluded patients with chronic disease, clinical evidence of pneumonia, pregnancy, recent antibiotic use, and history of hypersensitivity to the antibiotic to be used.