Objectives: To compare antibiotics and placebo in patients with clinically diagnosed acute maxillary sinusitis (AMS). To study whether sinus ultrasound examination would help to detect those patients who benefit from antibiotic therapy.
Design: A double-blind, randomised, placebo-controlled multicentre trial.
Setting: Nine primary care sites in Finland.
Subjects: 150 adult patients (mean age 39.7 years) with a clinical diagnosis of sinusitis.
Intervention: Antibiotics (amoxicillin 750 mg x 2, doxycycline 100 mg x 2 or penicillin V 1500 mg x 2) or placebo twice daily for 7 days; all patients were examined with sinus ultrasound after randomisation.
Main outcome measure: Clinical success (patients' report of recovery) in telephone interview at 2 weeks.
Results: A total of 146 patients completed the 2-week follow-up. Patients receiving antibiotics achieved a slightly higher rate of clinical success than patients receiving placebo (80% vs 66%; p = 0.068).
Conclusions: Antibiotics hasten symptom relief in AMS. Yet many patients recover in 2 weeks without antimicrobial treatment. Only half of patients with a clinical diagnosis of AMS have sinusitis in ultrasound examination.