Efficacy of a Topical Ear Formulation with a Pump Delivery System for the Treatment of Infectious Otitis Externa in Dogs: a Randomized Controlled Trial

In a randomised, multicentric field clinical trial on dogs with otitis externa, the efficacy of an hydrocortisone aceponate-gentamicinmiconazole otic suspension (Easotic, Virbac, Carros, France) applied once daily for 5 days was compared to that of a betamethasone valerate-gentamicin-clotrimazole otic suspension (Otomax, Schering Plough Animal Health, Levallois-Perret, France) applied twice daily for 7 days. One-hundred and seventy-six dogs with bacterial and/or fungal otitis externa were included in the study and received one of the two ear medications. On days 0, 5, 7 and 14 clinical signs, as well as bacteriological and fungal counts at cytology from ear samples, were graded using semi-quantitative scales. Bacterial and fungal cultures were also performed on day 0. A control visit was performed on day 49 to check for relapses. The aggregate clinical scores were reduced by 83.2% with Easotic and 86.2% with Otomax on day 14, with no significant difference between groups. Clinical recovery (>75% reduction of the aggregate score) was recorded in 72.2% of cases with Easotic and 69.9% of cases with Otomax on day 14. Microbial scores were reduced in both groups over the study period, with a higher cytological recovery rate on day 14 in the Easotic group (61.3%) versus Otomax (37%) (odd ratio=2.7). None of the dogs with clinical recovery on day 14 presented a relapse up to day 49. Side effects were minor and transient. In this study Easotic applied once daily for 5 days proved efficient and safe for the treatment of canine otitis externa.