Effect of amoxicillin-clavulanate in clinically diagnosed acute rhinosinusitis: a placebo-controlled, double-blind, randomized trial in general practice.

BACKGROUND Acute rhinosinusitis is one of the most common reasons for prescribing antibiotics in primary care. However, it is not clear whether antibiotics improve the outcome for patients with clinically diagnosed acute rhinosinusitis. We evaluated the effect of a combination product of amoxicillin-potassium clavulanate on adults with acute rhinosinusitis that was clinically diagnosed in a general practice setting. METHODS We conducted a randomized, placebo-controlled, double-blind trial with 252 adults recruited at 24 general practices and 2 outpatient clinics. Each patient had a history of purulent nasal discharge and maxillary or frontal pain for at least 48 hours. Patients were given amoxicillin, 875 mg, and clavulanic acid, 125 mg, or placebo twice daily for 6 days. Main outcome measures were time to cure (primary outcome), number of days during which rhinosinusitis restricted activities at home or work, and frequency of adverse effects (secondary outcomes). RESULTS The adjusted hazard ratio for the effect of amoxicillin-clavulanate was 0.99 (95% confidence interval [CI], 0.68-1.45) on time to cure and 1.28 (95% CI, 0.80-2.05) in the prespecified subgroup of patients with a positive rhinoscopy result. At 7 days the mean difference between amoxicillin-clavulanate and placebo was -0.29 (95% CI, -0.93 to 0.34) in the number of days with restrictions due to rhinosinusitis and -0.60 (95% CI, -1.41 to 0.21) in patients with a positive rhinoscopy result. At 7 days patients who took amoxicillin-clavulanate were more likely to have diarrhea (odds ratio, 3.89; 95% CI, 2.09-7.25). CONCLUSIONS Adult patients in general practice with clinically diagnosed acute rhinosinusitis experience no advantage with antibiotic treatment with amoxicillin-clavulanate and are more likely to experience adverse effects.