Context: Evidence to support antibiotic treatment for acute rhinosinusitis is limited, yet antibiotics are commonly used.
Objective: To determine the incremental effect of amoxicillin treatment over symptomatic treatments for adults with clinically diagnosed acute rhinosinusitis.
Design, setting, and participants: A randomized, placebo-controlled trial of adults with uncomplicated, acute rhinosinusitis were recruited from 10 community practices in Missouri between November 1, 2006, and May 1, 2009.
Interventions: Ten-day course of either amoxicillin (1500 mg/d) or placebo administered in 3 doses per day. All patients received a 5- to 7-day supply of symptomatic treatments for pain, fever, cough, and nasal congestion to use as needed.
Main outcome measures: The primary outcome was improvement in disease-specific quality of life after 3 to 4 days of treatment assessed with the Sinonasal Outcome Test-16 (minimally important difference of 0.5 units on a 0-3 scale). Secondary outcomes included the patient's retrospective assessment of change in sinus symptoms and functional status, recurrence or relapse, and satisfaction with and adverse effects of treatment. Outcomes were assessed by telephone interview at days 3, 7, 10, and 28.
Results: A total of 166 adults (36% male; 78% with white race) were randomized to amoxicillin (n = 85) or placebo (n = 81); 92% concurrently used 1 or more symptomatic treatments (94% for amoxicillin group vs 90% for control group; P = .34). The mean change in Sinonasal Outcome Test-16 scores was not significantly different between groups on day 3 (decrease of 0.59 in the amoxicillin group and 0.54 in the control group; mean difference between groups of 0.03 [95% CI, -0.12 to 0.19]) and on day 10 (mean difference between groups of 0.01 [95% CI, -0.13 to 0.15]), but differed at day 7 favoring amoxicillin (mean difference between groups of 0.19 [95% CI, 0.024 to 0.35]). There was no statistically significant difference in reported symptom improvement at day 3 (37% for amoxicillin group vs 34% for control group; P = .67) or at day 10 (78% vs 80%, respectively; P = .71), whereas at day 7 more participants treated with amoxicillin reported symptom improvement (74% vs 56%, respectively; P = .02). No between-group differences were found for any other secondary outcomes. No serious adverse events occurred.
Conclusion: Among patients with acute rhinosinusitis, a 10-day course of amoxicillin compared with placebo did not reduce symptoms at day 3 of treatment.
Trial registration: clinicaltrials.gov Identifier: NCT00377403.