Treatment of acute bacterial conjunctivitis: 1% fusidic acid viscous drops vs. 0.3% tobramycin drops

Background: A frequent cause of conjunctivitis is an acute bacterial infection, presenting with mucopurulent discharge and conjunctival hyperemia. The authors compared the clinical and microbiologic efficacy, safety and acceptability of I fusidic acid viscous drops (Fucithalmic) with 0.3% tobramycin ophthalmic solution (Tobrex) in the treatment of suspected bacterial conjunctivitis. Methods: Patients were recruited at 20 sites in Ontario, Saskatchewan and Alberta from October 1995 to December 1998. Patients who presented to their primary care physician with suspected bacterial conjunctivitis, as identified by conjunctival hyperemia and purulent or mucopurulent discharge, were eligible for the study. Patients were randomly assigned to receive 7 days of treatment with either 1% fusidic acid (one drop applied twice daily) or 0.3% tobramycin (one to two drops applied four to six times daily). The investigators were blinded as to treatment status. Bacteriologic samples were taken from the inferior conjunctival cul-de-sac on day 0 and at the end of treatment. Signs and symptoms of conjunctivitis were assessed at baseline and after 3 and 7 days of treatment. The acceptability of treatment was assessed by having the patient or the parent or guardian complete a questionnaire on degree of compliance and ease of use after 3 and 7 days of treatment. Results: Conjunctival swabs were obtained from 484 patients (410 over 9 years of age and 74 aged 2 to 9 years) to determine baseline bacteriology. Of the 484, 319 (65.9%) (63% of the older patients and 80% of those aged 2 to 9 years) had positive results of culture for bacteria. Ninety-four patients (19%) (63 [15%] of the older patients and 31 [42%] of those aged 2 to 9 years) had per-protocol pathogens as defined by quantitative bacteriology criteria. There was a direct correlation between the presence of mucopurulent discharge and the presence of per-protocol pathogens. There were no significant differences in clinical or bacteriologic efficacy between the treatment groups. Treatment compliance was similar between the treatment groups for the older patients; however, for those aged 2 to 9 years, compliance was significantly better in the fusidic acid group than in the tobramycin group (85% vs. 47%) (p <0.001). Significantly more patients in the fusidic acid group than in the tobramycin group rated treatment as convenient or very convenient, particularly among younger patients (97% vs. 54%) (p < 0.001). Interpretation: The clinical and bacteriologic efficacy of fusidic acid viscous drops combined with the convenience of a twice-daily dosage regimen establishes this antibiotic as first-line treatment for suspected acute bacterial conjunctivitis and a favourable alternative to other broad-spectrum antibiotics.